Engine Controls Self-Diagnostics - 6.6L Diesel: Diagnosis Chevrolet Silverado 2500

ON-BOARD DIAGNOSTICS

ECM is equipped with a self-diagnostic system which detects system failures or abnormalities. When a malfunction occurs, ECM will store a Diagnostic Trouble Code (DTC) and, in most cases, illuminate the Malfunction Indicator Lamp (MIL) located on instrument cluster.

There are 2 paths for accessing on-board diagnostics. It is necessary to access information through both paths, as each path presents some different information.

1. Generic OBD-II This provides all generic codes and some OEM codes, serial data PIDs required for generic OBD-II and some OEM PIDs, monitor status, pending codes and freeze frame.
2. OEM All DTCs, all PIDs, failure records, enhanced scan tool information and all other OEM scanner functions.

Scan Tool Snapshot

The scan tool can be set up to take a snapshot of the parameters available via serial data. The snapshot function records live data over a period of time. The recorded data can be played back and analyzed. The scan tool can also graph parameters singly or in combinations of parameters for comparison. The snapshot can be triggered manually at the time the symptom is noticed, or set up in advance to trigger when a DTC sets. An abnormal value captured in the recorded data may point to a system or component that needs to be investigated further. Refer to the scan tool user instructions for more information on the Snapshot function.

DIAGNOSTIC PROCEDURE

Diagnosis of computerized engine control system should be performed in the following order

1. Ensure all engine systems not related to computer system are operating properly. DO NOT proceed with testing unless all other problems have been repaired. Diagnostic system check must be performed before using specific DTC testing procedure. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) .
2. If no DTCs are present and a driveability problem exists, see SYMPTOMS in appropriate TROUBLE SHOOTING - NO CODES article. Doing so will help identify proper system or component to check in appropriate SYSTEM & COMPONENT TESTING article.
3. After necessary repairs are made, clear DTCs, verify vehicle will enter "closed loop" operation and ensure DTC does not reset.

RETRIEVING DIAGNOSTIC TROUBLE CODES

DTCs are retrieved using a Tech 2 scan tool, or other OBD-II compatible scan tool connected to OBD-II 16-pin Data Link Connector (DLC). See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS. (Scheme 15) DLC is located below left side of dash.

Diagnostic Procedures

Note. Do not perform this diagnostic if there is not a driveability concern, unless another procedure directs you to this diagnostic. Before you proceed with diagnosis, search for applicable service bulletins. Unless a diagnostic procedure instructs you, do NOT clear the DTCs. If there is a condition with the starting system, see appropriate STARTERS article in STARTING & CHARGING SYSTEMS. Ensure the battery has a full charge. Ensure the battery cables are clean and tight. Ensure the ECM grounds are clean, tight, and in the correct location.

1. Install a scan tool. Does the scan tool turn ON? If yes, go to next step. If no, see SCAN TOOL DOES NOT POWER UP in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
2. Turn ON the ignition, with the engine OFF. Attempt to establish communication with the listed control modules. If you are using a Tech 2, obtain the information using the Class 2 Message Monitor feature: Engine Control Module (ECM). Transmission Control Module (TCM). Body Control Module (BCM). Instrument Panel Cluster (IPC). Electronic Brake Control Module (EBCM). Heating, Ventilation, and Air Conditioning (HVAC). Does the scan tool communicate with all the listed control modules? If yes, go to next step. If no, see SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
3. Attempt to start the engine. Does the engine start and idle? If yes, go to next step. If no, see ENGINE CRANKS BUT DOES NOT RUN in appropriate TROUBLE SHOOTING - NO CODES article.
4. Select the DTC display function for the following control modules: ECM, TCM, BCM, IPC, EBCM and HVAC. Does the scan tool display any DTCs? If yes, go to next step. If no, go to step 9 .
5. With a scan tool, select Captured Info in order to store the powertrain DTC information. When complete, go to next step.
6. Does the scan tool display DTCs which begin with a "U"? If yes, see appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If no, go to next step.
7. Does the scan tool display DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681 or P1683? If yes, see «DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681 & P1683: ECM MEMORY»(ref-138411-S28765884622002041200000) under DIAGNOSTIC TESTS. If no, go to next step.
8. Does the scan tool display DTC P0562, P0563, P1637 or P1638? If yes, see appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS. If no, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) .
9. Is the customer's concern with the automatic transmission? If yes, see appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS. If no, go to next step.
10. Review the following symptoms. Hard start, surges/chuggles, lack of power, sluggishness, sponginess, fuel knock/combustion noise, hesitation, sag, stumble, cuts out, misses, poor fuel economy, rough, unstable, or incorrect idle and stalling and excessive smoke. See appropriate TROUBLE SHOOTING - NO CODES article. Did you find and correct the condition? If yes, system is okay. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) .

CLEARING DIAGNOSTIC TROUBLE CODES

There are 3 methods to clear DTCs.

Scan Tool

Scan tool is preferable way to clear DTC information. Freeze frame and failure record data will also be cleared. ECM adaptive learning and system monitors will only be cleared for those system which had a stored DTC.

SCAN TOOL USAGE

Scan tool is a specialized tester which, when connected to DLC, can be used to diagnose on-board computer control systems by providing instant access to circuit voltage information without need to crawl under dash or hood to backprobe sensors and connectors.

Scan tool reduces diagnostic time dramatically by furnishing input data (voltage signals) which can be compared to specification parameters. They may also furnish information on output device (solenoids and motors) status. However, status parameters only indicate output signals have been sent to devices by ECM; they do not indicate whether devices have responded properly to signal. Verify proper response at output device using a voltmeter or test light.

A problem may exist even if DTCs are not present. About 80 percent of driveability problems occur without setting DTCs. Sensors that are out of calibration will not set a DTC but will cause driveability problems.

Using a scan tool is the easiest method of checking sensor specifications and other data parameters. Scan tool is also useful in finding intermittent wiring problems by wiggling wiring harnesses and connections (key on, engine off) while observing data parameters.

Note. If erroneous voltage signals are suspected, verify tester information using a digital voltmeter and wiring schematic. If non-existent DTCs are displayed, DO NOT use scan tool for diagnosis. Contact tester manufacturer for additional information.

Scan Tool Display

Note. OBD-II vehicles have options available in the scan tool DTC mode to display enhanced information available. However, to fully utilize information and procedures requires the use of a Tech 2 scan tool. See scan tool operator's manual for additional information.

The following are Tech 2 scan tool sub-menus in the DTC INFO and SPECIFIC DTC modes

1. DTC INFO MODE Used to search for specific type of stored DTC information. There are 7 choices in this mode. Technician may be instructed to test DTCs in a certain manner. Follow the affected DTC test procedures. To get complete description of any status, hit ENTER key before pressing the desired "F" key.
2. DTC STATUS This selection will display any DTCs that have not run during the current ignition cycle or have reported a test failure during this ignition up to a maximum of 33 DTCs. A DTC test that runs and passes will cause affected DTC to be removed from scan tool screen.
3. FAIL THIS IGN. This selection will display all DTCs that have failed during the present ignition cycle.
4. HISTORY This selection will display only DTCs that are stored in the control module's history memory. It will not display type "D" DTCs. It will display all type "A" and type "B" DTCs that have the MIL illuminated and have failed within the last 40 warm-up cycles. It will also display type "C" DTCs that have failed within the 40 warm-up cycles.
5. LAST TEST FAIL This selection will only display DTCs that have failed the last time the test ran. If type "A" or "B" DTCs are displayed, the last test may have ran during the previous ignition cycle. For type "C" DTCs, the last failure must have occurred during the current ignition cycle to be displayed as LAST TEST FAIL.
6. MIL REQUEST This selection will only display DTCs that are requesting MIL illumination. Type "C" DTCs cannot be displayed using this option. This selection will report type "B" DTCs only after MIL illumination has been requested.
7. NOT RUN SCC Not Run Since Code Clear option will display up to 33 DTCs that have not run since DTCs were last cleared. Since any displayed DTCs have not run, their condition (passing or failing) is unknown.
8. TEST FAIL SCC Test Fail Since Code Clear selection will display all active and history DTCs that have reported a test failure since the last time DTCs were cleared. DTCs that last failed over 40 warm-up cycles before this option is selected will not be displayed.
9. FAILED SINCE CLEAR This message indicates the DTC has failed at least once within the last 40 warm-up cycles since the last time DTCs were cleared.
10. NOT RUN SINCE CL. Not Run Since Cleared message indicates that the selected diagnostic test has not run since the last time DTCs were cleared. Therefore, the diagnostic test status (passed or failed) is unknown. After DTCs are cleared, this message will continue to be displayed until the diagnostic test runs.
11. NOT RUN THIS IGN. Not Run This Ignition message indicates the selected diagnostic test has not run this ignition cycle.
12. TEST RAN AND PASSED This message indicates the selected diagnostic test has: Passed the last test. Ran and passed during this ignition cycle. Ran and passed since DTCs were last cleared. Test has not failed since DTCs were last cleared. If this message is displayed, repair is complete. If FAILED THIS IGN. message is displayed, repair is incomplete and further diagnosis is required.

Diagnostic Aids

The I/M System Status display provides an indication of when the control module has completed the required tests. This does not necessarily mean that the test has passed, only that a decision was made. If the diagnostic fails, a DTC will indicate the failure. If a failure indication is present for a DTC associated with one of the I/M regulated systems, the failure indication may prevent other required tests from running. For example, a DTC for the control circuit of the relay controlling an AIR pump may not be listed in the INSPECTION/MAINTENANCE SYSTEM DTCS table because this is a continuous test. If this DTC is set, the Active Tests for the AIR system may not run. The I/M System Status information may be useful for a technician to determine if diagnostics have run when verifying repairs.

Conditions for Running

Cold Start

1. The Engine Coolant Temperature (ECT) is below 133°F (56°C).
2. The Intake Air Temperature (IAT) is more than 20°F (-7°C).
3. The transmission fluid temperature is between 68-266°F (20-130°C).

If a step is interrupted before completion, perform the remaining portion of the set procedure. Any portion of the set procedure that requires the engine at operating temperature may be repeated. This will allow most of the diagnostic tests to run and the remaining tests can be performed using the individual system set procedures.

INSPECTION/MAINTENANCE SYSTEM DTCS

1. The Engine Coolant Temperature (ECT) is less than 133°F (56°C).
2. The Intake Air Temperature (IAT) is more than 20°F (7°C).
3. The transmission fluid temperature is between 68-266°F (20-130°C).

If the status does not update, the test outlined in this procedure can be repeated until the I/M System Status updates to YES. The I/M System Status does not indicate whether the test has passed or failed, only that a decision was made. When all of the diagnostics for a specific system have run and passed, the I/M System Status will update to YES. If a test for a specific system has failed, the I/M System Status will update to YES, indicating a determination was made, even if all of the required tests have not run. When a failure occurs, the Emission Related DTC portion of the I/M System Status display will indicate the Malfunction Indicator Lamp (MIL) is requested. The I/M System Status also registers the number of Diagnostic Trouble Codes (DTC). The first failure of a type "B" DTC does not constitute a final determination of pass or fail, and will not update the I/M System Status to YES. A second trip is required, and all the conditions to run must be met in order for the test to run again. These conditions may include a partial to complete engine cool down. The I/M System Status will update only when an emission related DTC fails the second time, or when all of the tests pass. If there is an impending failure, the system may require more time to run the diagnostic than was allotted in the set procedure. If the test does not run after numerous attempts and no DTC is set, review the appropriate scan tool data list and the service information for an indication of why the test does not complete. Some tests may abort due to changes in the conditions while the test is running. For example, changes in engine load, such as a cooling fan or an A/C compressor clutch turning ON, may cause the test to abort. If a diagnostic test is difficult to run, observe the I/M System Status display while maintaining the necessary enable conditions until the system status updates to YES.

The Engine Coolant Temperature (ECT) is between 133-219°F (56-104°C).

If the status does not update, the test outlined in this procedure can be repeated until the I/M System Status updates to YES. The I/M System Status does not indicate whether the test has passed or failed, only that a decision was made. When all of the diagnostics for a specific system have run and passed, the I/M System Status will update to YES. If a test for a specific system has failed, the I/M System Status will update to YES, indicating a determination was made, even if all of the required tests have not run. When a failure occurs, the Emission Related DTC portion of the I/M System Status display will indicate the Malfunction Indicator Lamp (MIL) is requested. The I/M System Status also registers the number of Diagnostic Trouble Codes (DTC). The first failure of a type "B" DTC does not constitute a final determination of pass or fail, and will not update the I/M System Status to YES. A second trip is required, and all the conditions to run must be met in order for the test to run again. These conditions may include a partial to complete engine cool down. The I/M System Status will update only when an emission related DTC fails the second time, or when all of the tests pass. If there is an impending failure, the system may require more time to run the diagnostic than was allotted in the set procedure. If the test does not run after numerous attempts and no DTC is set, review the appropriate scan tool data list and the service information for an indication of why the test does not complete. Some tests may abort due to changes in the conditions while the test is running. For example, changes in engine load, such as a cooling fan or an A/C compressor clutch turning ON, may cause the test to abort. If a diagnostic test is difficult to run, observe the I/M System Status display while maintaining the necessary enable conditions until the system status updates to YES.

DIAGNOSTIC TROUBLE CODE DEFINITIONS

DIAGNOSTIC TROUBLE CODE INDEX

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Scheme 36

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Inspect the fuse that supplies voltage to the MIL. Is the fuse open? If yes, go to step 10 . If no, go to next step.
3. Turn OFF the ignition. Disconnect the ECM. Turn ON the ignition, with the engine OFF. Connect a 3-amp fused jumper wire between the MIL control circuit and a good ground. Observe the MIL. Does the MIL illuminate? If yes, go to step 9 . If no, go to next step.
4. Did the fuse in the jumper wire open? If yes, go to step 11 . If no, go to next step.
5. Remove the Instrument Panel Cluster (IPC). See appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Test the MIL control circuit for an open between the ECM and the IPC and repair as necessary. Did you find and correct the condition? If yes, go to step 14 . If no, go to next step.
6. Probe the MIL battery positive voltage circuit at the IPC harness connector with a test lamp connected to a good ground. Does the test lamp illuminate? If yes, go to step 8 . If no, go to next step.
7. Repair the open in the MIL battery positive voltage circuit. After repairs, go to step 14 .
8. Inspect for poor connections at the harness connector of the IPC and repair as necessary. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 12 .
9. Inspect for poor connections at the harness connector of the ECM and repair as necessary. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 13 .
10. Repair the short to ground in the MIL battery positive voltage circuit. Replace the fuse. After repairs, go to step 14 .
11. Repair the short to voltage in the MIL control circuit. After repairs, go to step 14 .
12. Replace the IPC. See appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. After repairs, go to step 14 .
13. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
14. Operate the system in order to verify the repair. Did you correct the condition? If yes, system is okay. If no, go to step 2 .

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Turn ON the ignition, with the engine OFF. Does the MIL turn OFF when the ignition is turned ON? If yes, go to step 5 . If no, go to next step.
3. Turn OFF the ignition. Disconnect the ECM. Turn ON the ignition, with the engine OFF. Observe the MIL. Does the MIL illuminate? If yes, go to next step. If no, go to step 7 .
4. Remove the Instrument Panel Cluster (IPC). See appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Test the MIL control circuit for a short to ground between the ECM and the IPC. Did you find and correct the condition? If yes, go to step 8 . If no, go to step 6 .
5. Repair the MIL control circuit for a short to voltage. After repairs, go to step 8 .
6. Replace the IPC. See appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. After repairs, go to step 8 .
7. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
8. Operate the system in order to verify the repair. Did you correct the condition? If yes, system is okay. If no, go to step 2 .

DIAGNOSTIC TESTS

Note. Before clearing DTCs, perform powertrain diagnostic system check. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM. Record FREEZE FRAME and FAILURE RECORDS for reference during testing. Data will be erased when DTCs are cleared. If VCM is replaced, NEW VCM must be programmed using special manufacturer's equipment.

Conditions For Running DTC

1. DTCs P0192, P0193, or P1635 are not set.
2. The ignition is ON.

Conditions For Setting DTC

The actual FRP is less than 0.0 MPa at 0-400 RPM; or the actual FRP is less than 22.5 MPa at more than 600 RPM.

Action Taken When DTC Sets

1. The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.
3. The ECM will limit fuel injection.

Conditions For Clearing MIL/DTC

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Perform the Fuel System Diagnosis to check for leaks before proceeding. See appropriate BASIC DIAGNOSTIC PROCEDURES article. Did you find and correct the condition? If yes, go to step 14 . If no, go to next step.
3. Attempt to start the engine. Does the engine start and run? If yes, go to next step. If no, go to step 8 .
4. Install the J 44638 Vacuum Gauge on the fuel fitting located on the right side front of the engine. Start and run the engine at idle. Observe the vacuum gauge while increasing RPM slowly to 3000 RPM in park or neutral. Does the vacuum measure less than 5 in. through the entire RPM range? If yes, go to step 7 . If no, go to next step.
5. Replace the fuel filter. After repair, go to next step.
6. Start and run the engine at idle. Observe the vacuum gauge while increasing RPM slowly to 3000 RPM in park or neutral. Does the vacuum measure less than 5 in. through the entire RPM range? If yes, go to step 14 . If no, go to step 10 .
7. Start and idle the engine. Observe the Actual Fuel Rail Pressure with a scan tool. Does the Actual Fuel Rail Pressure measure less than or equal to 23 MPa? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-138411-S33805084052002041200000) .
8. Disconnect the FRP sensor. Observe the Actual Fuel Rail Pressure parameter with a scan tool. Does the Actual Fuel Rail Pressure measure more than 175 MPa? If yes, go to next step. If no, go to step 13 .
9. Attempt to start the engine with the FRP sensor disconnected. Does the engine start and run? If yes, go to step 11 . If no, diagnose fuel system high pressure side. See «FUEL SYSTEM DIAGNOSIS - HIGH PRESSURE SIDE»(ref-150429-S06204432152002111300000) under FUEL SYSTEMS (DIESEL) in SYSTEM & COMPONENT TESTING - TRUCKS -EXCEPT TRACKER article.
10. Check for a restriction in the fuel supply system. Repair as necessary. After repairs, go to step 14 .
11. Check for poor connections at the FRP sensor. Repair as necessary. Did you find and correct the condition? If yes, go to step 14 . If no, go to next step.
12. Replace the FRP sensor. After repairs, go to step 14 .
13. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
14. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
15. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

A restricted fuel supply line may cause DTCs P0087 and P1093 to set at the same time.

1. DTCs P0192, P0193, or P1635 are not set.
2. The ignition is ON.

The actual fuel pressure is more than 167 MPa.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.
3. The control module will limit fuel injection and fuel rail pressure.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Perform the Fuel System Diagnosis to check for fuel system leaks before proceeding. See appropriate BASIC DIAGNOSTIC PROCEDURES article. Did you find and correct the condition? If yes, go to step 6 . If no, go to next step.
3. Did DTC P0090 also set? If yes, see «DTC P0090: FUEL RAIL PRESSURE SENSOR CURRENT OUT OF RANGE»(ref-138411-S20369296622002041200000) . If no, go to next step.
4. Start the engine. Observe the Actual Fuel Rail Pressure on the scan tool. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Is the Actual Fuel Rail Pressure more 167 MPa? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-138411-S17095284352002041200000) .
5. Replace the FRP regulator. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
6. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
7. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

There are no driveability concerns associated with the fuel rail pressure regulator unless a DTC is present. The most likely cause of this DTC is a sticking fuel rail pressure regulator. If the fuel system pressure is actually too high, a fuel knock and smoke condition will exist.

1. DTCs P0192, P0193, or P1635 are not set.
2. The ignition is ON.

1. The difference between actual and desired FRP is more than 20 MPa.
2. Commanded fuel pump flow is 100 mm 3 /second or less.

Action Taken When DTC Sets - California

1. The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

Action Taken When DTC Sets - Federal

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.
4. The driver information center, if equipped, may display a message.

Conditions For Clearing MIL/DTC - California

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Use a scan tool in order to clear the MIL and the DTC.

Conditions For Clearing DTC - Federal

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
3. Use a scan tool in order to clear the DTC.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Did DTC P0090 also set? If yes, see «DTC P0090: FUEL RAIL PRESSURE SENSOR CURRENT OUT OF RANGE»(ref-138411-S20369296622002041200000) . If no, go to next step.
3. Did DTC P1093 also set? If yes, see «DTC P1093: FUEL RAIL PRESSURE OUT OF RANGE»(ref-138411-S27308629622002041500000) . If no, go to next step.
4. Start and run the engine at 2000 RPM. Observe the Actual Fuel Rail Pressure and the Desired Fuel Rail Pressure with a scan tool. Does the fuel pressure difference measure less than 20 MPa? If yes, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM. If no, go to next step.
5. Perform the Fuel Return System Diagnosis. See appropriate SYSTEM & COMPONENT TESTING article. Did you find and correct the condition? If yes, go to step 7 . If no, go to next step.
6. Replace the FRP regulator. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
7. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
8. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. The ignition is ON.
2. The commanded FRP regulator current is between 400-1500 mA.

The FRP regulator circuit current is not between 50-1600 mA.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Is DTC U1800 present also? If yes, diagnose DTC U1800. See appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If no, go to next step.
3. Attempt to start the engine. Does the engine start? If yes, go to next step. If no, go to step 5 .
4. Start the engine. Observe the Actual Fuel Rail Pressure and the Desired Fuel Rail Pressure with a scan tool. Does the scan tool display a pressure difference more than 5 MPa? If yes, go to step 6 . If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
5. Turn OFF the ignition. Disconnect the ECM connectors. Disconnect the FRP regulator connector. Measure the resistance from the control circuit of the FRP regulator to ground with a Digital Multimeter (DMM). Does the resistance measure infinite? If yes, go to step 15 . If no, go to step 13 .
6. Turn OFF the ignition. Disconnect the FRP regulator harness connector. Turn ON the ignition, with the engine OFF. Probe the supply circuit of the fuel rail pressure regulator with a J 34142-B Unpowered Test Lamp connected to a good ground. Does the test lamp illuminate? If yes, go to next step. If no, go to step 9 .
7. Turn OFF the ignition. Verify the FRP regulator harness connector is disconnected. Turn ON the ignition, with the engine OFF. Probe the control circuit of the FRP regulator with a test lamp connected to battery voltage. Does the test lamp illuminate? If yes, go to step 14 . If no, go to next step.
8. Disconnect the ECM connector containing the FRP regulator control circuit. Turn ON the ignition, with the engine OFF. Measure the voltage from the FRP regulator control circuit to a good ground with a DMM. Does the voltage measure 0 V? If yes, go to step 16 . If no, go to step 12 .
9. Turn OFF the ignition. Disconnect the ECM connector C2. Turn ON the ignition, with the engine OFF. Probe the ignition 1 voltage circuit of the harness connector with a test lamp that is connected to a good ground. Does the test lamp illuminate? If yes, go to next step. If no, go to step 11 .
10. Test for an open in the FRP supply circuit between the ECM and the FRP regulator. If a problem is found, repair as necessary. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 17 .
11. Repair the open in the ignition 1 voltage circuit to the ECM. After repairs, go to step 19 .
12. Repair the short to voltage in the control circuit between the ECM and the FRP regulator. After repairs, go to step 19 .
13. Test for a short to ground in the control circuit between the ECM and the FRP regulator. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 18 .
14. Inspect for poor connections at the FRP regulator. Repair the wiring as necessary. Did you find and correct the condition? If yes, go to step 19 . IF no, go to next step.
15. Replace the FRP regulator. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 19 .
16. Test for an open in the control circuit between the ECM and the FRP regulator. Did you find and correct the condition? If yes, go to step 19 . If no, go to next step.
17. Inspect for poor connections at the ECM. Repair the wiring as necessary. Did you find and correct the condition? If yes, go to step 19 . If no, go to next step.
18. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
19. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
20. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. DTC P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0234, P0236, P0237, P0238, P0335, P0336, or P1345 are not set.
2. The ignition 1 signal is between 9-18 volts.
3. The engine speed is less than 2500 RPM.
4. The engine speed is steady within a range of 50 RPM.
5. The Accelerator Pedal Position (APP) indicated angle is less than 50 percent.
6. The above conditions are present for more than 2 seconds.

The ECM detects that the actual MAF sensor voltage signal is not within a predetermined range of the calculated MAF value for more than 2 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Action Taken When the DTC Sets - Federal

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Use a scan tool in order to clear the MIL and the DTC.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Start the engine Monitor the Diagnostic Trouble Code (DTC) Information using the scan tool. Does the scan tool display any other DTCs set? If yes, diagnose those DTCs first. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC as specified in the supporting text or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-138411-S04477235132002041200000) .
4. Inspect the fuse in the ignition 1 voltage circuit of the MAF sensor. Is the fuse open? If yes, go to step 17 . If no, go to next step.
5. Turn OFF the ignition. Inspect for air leaks in the following components: The air induction system and the turbocharger system. The MAF sensor O-ring seal. The boost pressure sensor seal. The EGR throttle valve solenoid, diaphragm, or vacuum hose. The EGR valve solenoid valve diaphragm, or vacuum hose. The EGR vent solenoid or vacuum hose. Inspect for the following conditions: Any kinks or restrictions in any of the EGR solenoid vacuum hoses. An obstructed intake air duct or a dirty air filter element. Any debris that is blocking the air sensing filaments of the MAF sensor. A MAF sensor that is installed backwards. A restricted exhaust system. Did you find and correct the condition? If yes, go to step 26 . If no, go to next step.
6. Turn ON the ignition, with the engine OFF. Observe both the BARO kPa and the boost pressure sensor kPa with a scan tool. Does the scan tool indicate that the difference between the sensors is equal to or less than 8 kPa? If yes, go to next step. If no, see «DTC P0107: MAP SENSOR CIRCUIT - LOW VOLTAGE (CA)»(ref-138411-S24307882352002041200000) , «DTC P0107: BARO SENSOR CIRCUIT - LOW PRESSURE (FED)»(ref-138411-S10479283912002041500000) , «DTC P0108: BARO SENSOR CIRCUIT - HIGH PRESSURE (FED)»(ref-138411-S08925119672002041500000) or «DTC P0108: MAP SENSOR CIRCUIT - HIGH VOLTAGE (CA)»(ref-138411-S07459840092002041200000) .
7. Start the engine and allow the engine to idle. Observe the MAF sensor g/s with a scan tool. Move the harness and the connector of the MAF sensor. Does the movement of the harness or the connector affect the MAF sensor g/s? If yes, go to step 21 . If no, go to next step.
8. Observe the MAF sensor g/s with a scan tool. Is the MAF sensor g/s less than 16 g/s? If yes, go to step 11 . If no, go to next step.
9. Observe the MAF sensor g/s with a scan tool. Is the MAF sensor g/s more than 445 g/s? If yes, go to next step. If no, go to step 11 .
10. Disconnect the harness connector of the MAF sensor. Is the MAF sensor g/s more than 445 g/s? If yes, go to step 15 . If no, go to next step.
11. Turn OFF the engine. Turn ON the ignition, with the engine OFF. Disconnect the harness connector of the MAF sensor. Connect a test lamp between the ignition 1 voltage circuit of the MAF sensor and a good ground. Does the test lamp illuminate? If yes, go to next step. If no, go to step 17 .
12. Connect a test lamp between the ignition 1 voltage circuit of the MAF sensor and the low reference circuit of the MAF sensor. Does the test lamp illuminate? If yes, go to next step. If no, go to step 18 .
13. Connect a 3-amp fused jumper wire between the signal circuit of the IAT sensor and the signal circuit of the MAF sensor. Observe the MAF sensor value with a scan tool. Did the MAF sensor value change to 499 g/s? If yes, go to step 22 . If no, go to next step.
14. Turn OFF the ignition. Disconnect the fused jumper wire. Disconnect the ECM. Test the signal circuit between the ECM and the MAF sensor for the following conditions: A high resistance or an open. A short to ground. A short to the low reference circuit of the MAF sensor or IAT sensor. Did you find and correct the condition? If yes, go to step 26 . If no, go to step 16 .
15. Turn OFF the ignition. Disconnect the ECM. Turn ON the ignition, with the engine OFF. Measure the voltage from the signal circuit of the MAF sensor to a good ground. Does the voltage measure near 0 V? If yes, go to next step. If no, go to step 19 .
16. Use a Digital Multimeter (DMM) in order to test for continuity at the harness connector of the ECM from the signal circuit of the MAF sensor to all other circuits at both ECM connectors. Does the DMM indicate continuity between any other circuit? If yes, go to step 20 . If no, go to step 23 .
17. Repair the short to ground or an open in the ignition 1 voltage circuit of the MAF sensor. Replace the fuse if necessary. Did you complete the repair? If yes, go to step 26 . If no, go to step 24 .
18. Repair the high resistance or an open in the low reference circuit of the MAF sensor. Did you complete the repair? If yes, go to step 26 . If no, go to step 23 .
19. Repair the short to voltage in the signal circuit of the MAF sensor. After repairs, go to step 26 .
20. Repair the circuits that are shorted together. After repairs, go to step 26 .
21. Repair the harness or the connections as necessary. After repairs, go to step 26 .
22. Inspect for poor connections at the harness connector of the MAF sensor. Did you find and correct the condition? If yes, go to step 26 . If no, go to step 24 .
23. Inspect for poor connections at the harness connector of the ECM. Did you find and correct the condition? If yes, go to step 26 . If no, go to step 25 .
24. Replace the MAF/IAT sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 26 .
25. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
26. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
27. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

Inspect for the following conditions

1. Any unmetered air. Any unmetered air that enters the engine downstream of the MAF sensor may cause this DTC to set.
2. A sluggish or unresponsive MAF sensor. A short between the signal circuit of the MAF sensor and the signal circuit of the Intake Air Temperature (IAT) sensor. This will cause the MAF sensor to have a very limited output voltage range.
3. A malfunctioning MAF sensor can cause excessive engine emissions.
4. An open on the 5-volt reference circuit of the Barometric (BARO) pressure sensor may cause this DTC to set.
5. A short to ground on the signal circuit of the BARO sensor may cause this DTC to set.
6. The signal circuit of the BARO sensor shorted to 5 volts may cause this DTC to set.
7. An open signal circuit of the BARO sensor may cause this DTC to set.
8. The MAF display should increase from 42-50 g/s at idle to 420 g/s or more at the 2-3 shift during a Wide Open Throttle (WOT) acceleration. If not, inspect for a restriction in the induction system or the exhaust system.
9. If the condition is intermittent, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.

1. The engine is running for more than 2 seconds.
2. The engine speed is more than 500 RPM.
3. The ignition 1 signal is more than 9 volts.
4. The above conditions are present for more than 2 seconds.

1. The ECM detects that the MAF sensor signal is less than 0.5 volt. This equals a MAF value of less than 16 g/s.
2. The condition is present for more than 2 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Start the engine. Monitor the Diagnostic Trouble Code (DTC) information using the scan tool. Does the scan tool display any other DTCs set? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as closely as possible to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-138411-S28939280022002041200000) .
4. Inspect the fuse in the ignition 1 voltage circuit of the MAF sensor. Is the fuse open? If yes, go to step 9 . If no, go to next step.
5. Turn OFF the ignition. Inspect for air leaks in the following components: The air induction system and the turbocharger system. The MAF sensor O-ring seal. The boost pressure sensor seal. Inspect for the following conditions: An obstructed intake air duct or a dirty air filter element. Any debris that is blocking the air sensing filaments of the MAF sensor. A MAF sensor that is installed backwards. A restricted exhaust system. Did you find and correct the condition? If yes, go to step 20 . If no, go to next step.
6. Start the engine and allow the engine to idle. Observe the MAF sensor g/s with a scan tool. Move the harness and the connector of the MAF sensor. Does the movement of the harness or the connector affect the MAF sensor g/s? If yes, go to step 15 . If no, go to next step.
7. Turn OFF the engine. Turn ON the ignition, with the engine OFF. Disconnect the harness connector of the MAF sensor. Connect a test lamp between the ignition 1 voltage circuit of the MAF sensor and a good ground. Does the test lamp illuminate? If yes, go to next step. If no, go to step 13 .
8. Connect a 3-amp fused jumper wire between the signal circuit of the IAT sensor and the signal circuit of the MAF sensor. Observe the MAF sensor value with a scan tool. Did the MAF sensor value change to 499 g/s? If yes, go to step 16 . If no, go to step 10 .
9. Use a Digital Multimeter (DMM) in order to test for continuity between the ignition 1 voltage circuit of the MAF sensor and ground. Does the DMM indicate continuity? If yes, go to step 12 . If no, go to step 16 .
10. Turn OFF the ignition. Disconnect the fused jumper wire. Disconnect the ECM. Test the signal circuit between the ECM and the MAF sensor for the following conditions: A high resistance or an open. A short to ground. A short to the low reference circuit of the MAF sensor or IAT sensor. Did you find and correct the condition? If yes, go to step 20 . If no, go to next step.
11. Use a DMM in order to test for continuity at the harness connector of the ECM from the signal circuit of the MAF sensor to all other circuits at both ECM connectors. Does the DMM indicate continuity between any other circuit? If yes, go to step 14 . If no, go to step 17 .
12. Repair the short to ground in the ignition 1 voltage circuit of the MAF sensor. Replace the fuse as needed. After repairs, go to step 20 .
13. Repair the open in the ignition 1 voltage circuit of the MAF sensor. After repairs, go to step 20 .
14. Repair the circuits that are shorted together. After repairs, go to step 20 .
15. Repair the harness or the connections as necessary. After repairs, go to step 20 .
16. Inspect for poor connections at the harness connector of the MAF sensor. Did you find and correct the condition? If yes, go to step 20 . If no, go to step 18 .
17. Inspect for poor connections at the harness connector of the ECM. Did you find and correct the condition? If yes, go to step 20 . If no, go to step 19 .
18. Replace the MAF/IAT sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 20 .
19. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
20. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
21. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

Inspect for the following conditions

1. Any unmetered air--Any unmetered air that enters the engine downstream of the MAF sensor may cause this DTC to set.
2. A sluggish or unresponsive MAF sensor--A short between the signal circuit of the MAF sensor and the signal circuit of the Intake Air Temperature (IAT) sensor. This will cause the MAF sensor to have a very limited output voltage range.
3. Any debris that may be blocking the sensing elements of the MAF sensor.
4. Any water in the air induction system.
5. The MAF display should increase from 42-50 g/s at idle to 420 g/s or more at the 2-3 shift during a Wide Open Throttle (WOT) acceleration. If not, inspect for a restriction in the induction system or the exhaust system.
6. If the condition is intermittent, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.

1. The engine is running for more than 2 seconds.
2. The engine speed is more than 500 RPM.
3. The ignition 1 signal is more than 9 volts.
4. The above conditions are present for more than 2 seconds.

1. The ECM detects that the MAF sensor signal is more than 4.8 volts. This equals a MAF value of more than 490 g/s.
2. The condition is present for more than 2 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Start the engine. Monitor the Diagnostic Trouble Code (DTC) information using the scan tool. Does the scan tool display any other DTCs set? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-138411-S13602536072002041200000) .
4. Start the engine and allow the engine to idle. Observe the MAF sensor g/s with a scan tool. Move the harness and the connector of the MAF sensor. Does the movement of the harness or the connector affect the MAF sensor g/s? If yes, go to step 13 . If no, go to next step.
5. Observe the MAF sensor g/s with a scan tool. Disconnect the harness connector of the MAF sensor. Is the MAF sensor g/s more than 444 g/s? If yes, go to step 8 . If no, go to next step.
6. Turn OFF the engine. Turn ON the ignition, with the engine OFF. Connect a test lamp between the ignition 1 voltage circuit of the MAF sensor and the low reference circuit of the MAF sensor. Does the test lamp illuminate? If yes, go to step 14 . If no, go to next step.
7. Disconnect the ECM. Test the low reference circuit between the ECM and the MAF sensor for a high resistance or an open. Does the Digital Multimeter (DMM) indicate good continuity? If yes, go to step 15 . If no, go to step 10 .
8. Turn OFF the ignition. Disconnect the harness connectors of the ECM. Turn ON the ignition, with the engine OFF. Test the signal circuit of the MAF sensor for a short to voltage. Does the DMM indicate a short to voltage? If yes, go to step 11 . If no, go to next step.
9. Use a DMM in order to test for continuity at the harness connector of the ECM from the signal circuit of the MAF sensor to all other circuits at both ECM connectors. Does the DMM indicate continuity between any other circuit? If yes, go to step 12 . If no, go to step 15 .
10. Repair the high resistance or an open in the low reference circuit of the MAF sensor. After repairs, go to step 18 .
11. Repair the short to voltage in the signal circuit of the MAF sensor. After repairs, go to step 18 .
12. Repair the circuits that are shorted together. After repairs, go to step 18 .
13. Repair the harness or the connections as necessary. After repairs, go to step 18 .
14. Inspect for poor connections at the harness connector of the MAF sensor. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 16 .
15. Inspect for poor connections at the harness connector of the ECM. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 17 .
16. Replace the MAF/IAT sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 18 .
17. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
18. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
19. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. A sluggish or unresponsive MAF sensor. A short between the signal circuit of the MAF sensor and the signal circuit of the Intake Air Temperature (IAT) sensor. This will cause the MAF sensor to have a very limited output voltage range.
2. Any water in the air induction system.
3. If the condition is intermittent, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.

1. DTCs P0101, P0102, P0103, P0107, P0108, P0116, P0117, P0118, P0236, P0237, P0238, P0335, P0336, P0404, P0405, P0406, or P0500 is not set.
2. The engine speed is between 500-3600 RPM.
3. The engine run time is more than 8 seconds.
4. The vehicle speed is less than 100 MPH.
5. The Mass Air Flow (MAF) is less than 444 g/s.
6. The Engine Coolant Temperature (ECT) is more than 20°C (68°F).
7. The Power Take Off (PTO) is OFF.
8. The above conditions exist for 5 seconds.

The difference between the BARO sensor and the EGR vacuum sensor when the EGR is inactive is more than 10 kPa for 6 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Turn OFF the ignition. Inspect the BARO sensor for a plugged port. Did you find and correct the condition? If yes, go to step 22 . If no, go to next step.
3. Start the engine. Allow the engine to reach operating temperature. Turn OFF the ignition. Turn ON the ignition, with the engine OFF. Observe the BARO sensor pressure and the EGR vacuum sensor pressure with a scan tool. Is the difference between the sensors more than 10 kPa? If yes, go to step 7 . If no, go to next step.
4. Start the engine. Command the EGR duty cycle to 0 percent with a scan tool. Observe the BARO sensor pressure and the EGR vacuum sensor pressure with the scan tool. Is the difference between the sensors more than 10 kPa? If yes, go to step 12 . If no, go to next step.
5. Turn OFF the ignition. Connect a hand vacuum pump to the BARO sensor port. Turn ON the ignition, with the engine OFF. Monitor the BARO sensor pressure with the scan tool. Apply vacuum SLOWLY 1 in. Hg at a time. Each inch of vacuum should result in a 3-4 kPa drop in the BARO sensor pressure. Increase the vacuum to 20 in. Hg. Does the BARO sensor pressure decreases smoothly through the test? If yes, go to next step. If no, go to step 7 .
6. Disconnect the hand vacuum pump from the BARO sensor port. Does the BARO sensor pressure return to the original value that was observed in step 3 ? If yes, see «DIAGNOSTIC AIDS»(ref-138411-S11690282732002041200000) . If no, go to step 20 .
7. Turn OFF the ignition. Disconnect the BARO sensor electrical connector. Turn ON the ignition, with the engine OFF. Does the BARO sensor pressure measure more than 44 kPa? If yes, go to step 17 . If no, go to next step.
8. Connect a test lamp to a good ground. Probe the 5-volt reference circuit of the BARO sensor with the test lamp. Perform a voltage drop test across the test lamp with a Digital Multimeter (DMM). Does the voltage measure more than 4.4 V? If yes, go to next step. If no, go to step 16 .
9. Does the voltage measure more than 5.2 V? If yes, go to step 13 . If no, go to next step.
10. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the BARO sensor and the signal circuit of the BARO sensor. Does the BARO sensor pressure measure more than 110 kPa? If yes, go to next step. If no, go to step 15 .
11. Connect a test lamp to battery positive voltage. Probe the low reference circuit of the BARO sensor with the test lamp. Does the test lamp illuminate? If yes, go to step 18 . If no, go to step 14 .
12. Inspect for the following conditions: Misrouted vacuum lines. A skewed EGR vacuum sensor. Repair as necessary. After repairs, go to step 22 .
13. Test the 5-volt reference circuit of the BARO sensor for a short to voltage. Did you find and correct the condition? If yes, go to step 22 . If no, go to step 21 .
14. Test the low reference circuit of the BARO sensor for high resistance or an open. Did you find and correct the condition? If yes, go to step 22 . If no, go to step 19 .
15. Test the signal circuit of the BARO sensor for the following conditions: A short to ground. An open. High resistance. Repair as necessary. Did you find and correct the condition? If yes, go to step 22 . If no, go to step 19 .
16. Test the 5-volt reference circuit of the BARO sensor for the following conditions: A short to ground. An open High resistance. Did you find and correct the condition? If yes, go to step 22 . If no, go to step 19 .
17. Test the signal circuit of the BARO sensor for a short to voltage. Did you find and correct the condition? If yes, go to step 22 . If no, go to step 21 .
18. Inspect the BARO sensor for poor connections. Did you find and correct the condition? If yes, go to step 22 . If no, go to step 20 .
19. Inspect the ECM for poor connections. Did you find and correct the condition? If yes, go to step 22 . If no, go to step 21 .
20. Replace the BARO sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 22 .
21. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
22. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
23. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. Inspect for any condition that would cause the ECM to receive a false BARO reading including the following: A skewed EGR vacuum sensor. A skewed BARO sensor. High circuit resistance, inspect for the following conditions: Rubbed wire insulation. Wire corrosion. Terminal corrosion.
2. If an intermittent condition exists, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.

1. DTCs P0101, P0102, P0103, P0107, P0108, P0116, P0117, P0118, P0236, P0237, P0238, P0335, P0336, or P0500 is not set.
2. The engine speed is between 500-900 RPM.
3. The engine run time is more than 20 seconds.
4. The accelerator pedal angle is less than 20 percent.
5. The vehicle speed is less than 25 MPH.
6. The Mass Air Flow (MAF) is less than 50 g/s.
7. The Engine Coolant Temperature (ECT) is more than 176°F (80°C).
8. The Power Take Off (PTO) is OFF.
9. The above conditions exist for 5 seconds.

The difference between the BARO sensor and the boost sensor is more than 20 kPa for 2 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

Conditions For Clearing DTC

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Use a scan tool in order to clear the DTC.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Turn OFF the ignition. Inspect the BARO sensor for a plugged port. Did you find and correct the condition? If yes, go to step 20 . If no, go to next step.
3. Turn ON the ignition, with the engine OFF. Monitor the scan tool and record the BARO sensor pressure. Compare the BARO sensor pressure to that of a known-good vehicle. Is the pressure difference between the vehicles less than 5 kPa? If yes, go to next step. If no, go to step 6 .
4. Connect a hand vacuum pump to the BARO sensor port. Monitor the BARO sensor pressure with the scan tool. Apply vacuum SLOWLY 1 in. Hg at a time. Each inch of vacuum should result in a 3-4 kPa drop in the BARO sensor pressure. Increase the vacuum to 20 in. Hg. Does the scan tool indicate that the BARO sensor pressure decreases smoothly through the test? If yes, go to next step. If no, go to step 6 .
5. Disconnect the hand vacuum pump from the BARO sensor port. Does the BARO sensor pressure return to the original value that was observed in step 3 ? If yes, see «DIAGNOSTIC AIDS»(ref-138411-S10676607882002041500000) . If no, go to step 18 .
6. Turn OFF the ignition. Disconnect the BARO sensor electrical connector. Turn ON the ignition, with the engine OFF. Does the scan tool indicate that the BARO sensor pressure is more than 44 kPa? If yes, go to step 15 . If no, go to next step.
7. Connect a test lamp to a good ground. Probe the 5-volt reference circuit of the BARO sensor with the test lamp. Perform a voltage drop test across the test lamp with a DMM. Does the voltage measure more than 4.4 V? If yes, go to next step. If no, go to step 14 .
8. Does the voltage measure more than 5.2 V? If yes, go to step 11 . If no, go to next step.
9. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the BARO sensor and the signal circuit of the BARO sensor. Does the scan tool indicate the BARO sensor pressure is more than 200 kPa? If yes, go to next step. If no, go to step 13 .
10. Connect a test lamp to battery positive voltage. Probe the low reference circuit of the BARO sensor with the test lamp. Does the test lamp illuminate? If yes, go to step 16 . If no, go to step 12 .
11. Test the 5-volt reference circuit of the BARO sensor for a short to voltage. Did you find and correct the condition? If yes, go to step 20 . If no, go to step 19 .
12. Test the low reference circuit of the BARO sensor for high resistance or an open. Did you find and correct the condition? If yes, go to step 20 . If no, go to step 17 .
13. Test the signal circuit of the BARO sensor for the following conditions: A short to ground. An open. High resistance. Repair as necessary. Did you find and correct the condition? If yes, go to step 20 . If no, go to step 17 .
14. Test the 5-volt reference circuit of the BARO sensor for the following conditions: A short to ground. An open. High resistance. Repair as necessary. Did you find and correct the condition? If yes, go to step 20 . If no, go to step 17 .
15. Test the signal circuit of the BARO sensor for a short to voltage. Did you find and correct the condition? If yes, go to step 20 . If no, go to step 19 .
16. Inspect the BARO sensor for poor connections. Did you find and correct the condition? If yes, go to step 20 . If no, go to step 18 .
17. Inspect the ECM for poor connections. Did you find and correct the condition? If yes, go to step 20 . If no, go to step 19 .
18. Replace the BARO sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 20 .
19. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
20. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
21. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. Inspect for any condition that would cause the ECM to receive a false BARO reading including the following: A skewed boost sensor. A skewed BARO sensor. High circuit resistance, inspect for the following conditions: Rubbed wire insulation. Wire corrosion. Terminal corrosion.
2. If an intermittent condition exists, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.

The engine is running.

The BARO is less than 44 kPa for 10 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Install a scan tool. Start the engine. Monitor the Diagnostic Trouble Code (DTC) Information using the scan tool. Does the scan tool indicate that DTC P1639 is current? If yes, see «DTC P1639: 5-VOLT REFERENCE 2 CIRCUIT»(ref-138411-S29319932602002041200000) . If no, go to next step.
3. Observe the BARO sensor pressure with a scan tool. Does the scan tool indicate that the pressure is less than 44 kPa? If yes, go to step 5 . If no, go to next step.
4. Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
5. Turn OFF the ignition. Disconnect the MAP sensor electrical connector. Turn ON the ignition, with the engine OFF. Measure the voltage from the 5-volt reference circuit of the MAP sensor to a good ground. Does the voltage measure near 5 V? If yes, go to next step. If no, go to step 7 .
6. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the BARO sensor and the signal circuit of the BARO sensor. Does the scan tool indicate that the BARO sensor pressure is more than 110 kPa? If yes, go to step 9 . If no, go to step 8 .
7. Test the 5-volt reference circuit of the BARO sensor for a high resistance or an open. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 10 .
8. Test the signal circuit of the BARO sensor for a short to ground, low reference or an open. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 10 .
9. Inspect for poor connections at the BARO sensor. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 11 .
10. Inspect for poor connections at the ECM. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 12 .
11. Replace the BARO sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 13 .
12. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
13. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
14. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

The ignition is ON.

The BARO is less than 44 kPa for 2 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Use a scan tool in order to clear the DTC.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Install a scan tool. Start the engine. Monitor the Diagnostic Trouble Code (DTC) Information with the scan tool. Does the scan tool indicate that DTC P1639 is current? If yes, see «DTC P1639: 5-VOLT REFERENCE 2 CIRCUIT»(ref-138411-S29319932602002041200000) . If no, go to next step.
3. Observe the BARO sensor pressure with a scan tool. Does the scan tool indicate that the pressure is less than 44 kPa? If yes, go to step 5 . If no, go to next step.
4. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
5. Turn OFF the ignition. Disconnect the BARO sensor electrical connector. Turn ON the ignition, with the engine OFF. Connect a test lamp to a good ground. Probe the 5-volt reference circuit of the BARO sensor with a test lamp. Does the test lamp illuminate? If yes, go to next step. If no, go to step 7 .
6. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the BARO sensor and the signal circuit of the BARO sensor. Does the scan tool indicate that the BARO sensor pressure is more than 110 kPa? If yes, go to step 9 . If no, go to step 8 .
7. Test the 5-volt reference circuit of the BARO sensor for high resistance or an open. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 10 .
8. Test the signal circuit of the BARO sensor for a short to ground, low reference, or an open. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 10 .
9. Inspect for poor connections at the BARO sensor. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 11 .
10. Inspect for poor connections at the ECM. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 12 .
11. Replace BARO sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 13 .
12. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
13. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
14. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

The engine is running.

The BARO is more than 110 kPa for 10 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Turn ON the ignition, with the engine OFF. Observe the BARO sensor pressure with a scan tool. Does the scan tool indicate that the pressure is more than 110 kPa? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
4. Monitor the Diagnostic Trouble Code (DTC) Information with a scan tool. Does the scan tool indicate that DTC P1639 is current? If yes, go to step 7 . If no, go to next step.
5. Turn OFF the ignition. Disconnect the electrical connector of the BARO sensor. Turn ON the ignition, with the engine OFF. Does the scan tool indicate that the BARO sensor pressure is less than 44 kPa? If yes, go to next step. If no, go to step 10 .
6. Connect a test lamp to battery positive voltage. Probe the low reference circuit of the BARO sensor with the test lamp. Does the test lamp illuminate brightly? If yes, go to step 15 . If no, go to step 14 .
7. Turn OFF the ignition. Disconnect the electrical connector of the BARO sensor. Turn ON the ignition, with the engine OFF. Does the scan tool indicate that the BARO sensor pressure is less than 44 kPa? If yes, go to next step. If no, go to step 11 .
8. Disconnect the electrical connector of the boost sensor. Does the scan tool indicate that the boost sensor pressure is less than 38 kPa? If yes, go to next step. If no, go to step 12 .
9. Disconnect the electrical connector of the EGR vacuum sensor. Does the scan tool indicate that the EGR vacuum sensor pressure is less than 18 kPa? If yes, see «DTC P1639: 5-VOLT REFERENCE 2 CIRCUIT»(ref-138411-S29319932602002041200000) . If no, go to step 13 .
10. Test the signal circuit of the BARO sensor for a short to 5 volts. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 18 .
11. Test the signal circuit of the BARO sensor for a short to battery voltage. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 18 .
12. Test the signal circuit of the boost sensor for a short to battery voltage. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 18 .
13. Test the signal circuit of the EGR vacuum sensor for a short to battery voltage. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 18 .
14. Test the low reference circuit of the BARO sensor for high resistance or an open. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 16 .
15. Inspect for poor connections at the BARO sensor. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 17 .
16. Inspect for poor connections at the ECM. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 18 .
17. Replace the BARO sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 19 .
18. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
19. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
20. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

The ignition is ON.

The BARO is more than 110 kPa for 2 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Use a scan tool in order to clear the DTC.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Turn ON the ignition, with the engine OFF. Observe the BARO sensor pressure with a scan tool. Does the scan tool indicate that the pressure is more than 110 kPa? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
4. Monitor the Diagnostic Trouble Code (DTC) Information with a scan tool. Does the scan tool indicate that DTC P1639 is current? If yes, go to step 7 . If no, go to next step.
5. Turn OFF the ignition. Disconnect the electrical connector of the BARO sensor. Turn ON the ignition, with the engine OFF. Does the scan tool indicate that the BARO sensor pressure is less than 44 kPa? If yes, go to next step. If no, go to step 9 .
6. Connect a test lamp to battery positive voltage. Probe the low reference circuit of the BARO sensor with the test lamp. Does the test lamp illuminate brightly? If yes, go to step 13 . If no, go to step 12 .
7. Turn OFF the ignition. Disconnect the electrical connector of the BARO sensor. Turn ON the ignition, with the engine OFF. Does the scan tool indicate that the BARO sensor pressure is less than 44 kPa? If yes, go to next step. If no, go to step 10 .
8. Disconnect the electrical connector of the boost sensor. Does the scan tool indicate that the boost sensor pressure is less than 50 kPa? If yes, see «DTC P1639: 5-VOLT REFERENCE 2 CIRCUIT»(ref-138411-S29319932602002041200000) . If no, go to step 11 .
9. Test the signal circuit of the BARO sensor for a short to 5 volts. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 16 .
10. Test the signal circuit of the BARO sensor for a short to battery voltage. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 16 .
11. Test the signal circuit of the Boost sensor for a short to battery voltage. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 16 .
12. Test the low reference circuit of the BARO sensor for high resistance or an open. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 14 .
13. Inspect for poor connections at the BARO sensor. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 15 .
14. Inspect for poor connections at the ECM. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 16 .
15. Replace the BARO sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 17 .
16. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
17. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
18. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. DTCs P0116, P0117, P0118, P0128 are not set.
2. The Engine Coolant Temperature (ECT) is less than 122°F (50°C).

The IAT is more than 298°F (148°C) for 2 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Install a scan tool. Turn ON the ignition, with the engine OFF. Observe the IAT sensor temperature with a scan tool. Is the IAT sensor temperature more than 262°F (128°C)? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC reset? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-138411-S22980495132002041200000) .
4. Turn OFF the Ignition. Disconnect the MAF/IAT sensor. Turn ON the ignition, with the engine OFF. Observe the IAT sensor temperature with a scan tool. Is the IAT sensor temperature less than -38°F (-39°C)? If yes, go to step 7 . If no, go to next step.
5. Test the signal circuit of the IAT sensor for a short to ground and repair as necessary. Did you find and correct the condition? If yes, go to step 10 . If no, go to step 8 .
6. Test for an intermittent and for a poor connection at the IAT sensor. Did you find and correct the condition? If yes, go to step 10 . If no, go to next step.
7. Replace the MAF/IAT sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 10 .
8. Turn OFF the ignition. Disconnect the ECM. Inspect for poor connection at the ECM harness connector. Did you find and correct the condition? If yes, go to step 10 . If no, go to next step.
9. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
10. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
11. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. When the vehicle is at ambient temperature the IAT sensor and ECT sensor temperatures should be relatively close to each other. See appropriate SENSOR OPERATING RANGE CHARTS article.
2. If an intermittent condition exists, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.

1. DTCs P0116, P0117, P0118, P0128 are not set.
2. The engine run time is more than 8 minutes.

The IAT is less than -39°C (-38°F) for more than 2 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Install a scan tool. Turn ON the ignition, with the engine OFF. Observe the IAT sensor temperature with a scan tool. Is the IAT sensor temperature less than -36°F (-38°C)? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC reset? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-138411-S41348493912002041200000) .
4. Turn OFF the ignition. Disconnect the MAF/IAT sensor. Connect a Digital Multimeter (DMM) between the signal circuit and the low reference circuit of the IAT sensor harness. Turn ON the ignition. Does the DMM voltage measure more than 5 V? If yes, go to next step. If no, go to step 6 .
5. Test the signal circuit for a short to voltage. Repair as necessary. Did you find and correct the condition? If yes, go to step 14 . If no, see «DIAGNOSTIC AIDS»(ref-138411-S41348493912002041200000) .
6. Turn OFF the ignition. Disconnect the IAT sensor. Connect a 3-amp fused jumper wire between the signal circuit of the IAT sensor and the low reference circuit at the IAT sensor. Turn ON the ignition, with the engine OFF. Observe the IAT sensor temperature with a scan tool. Is the IAT sensor temperature more than 262°F (128°C)? If yes, go to step 10 . If no, go to next step.
7. Turn OFF the ignition. Connect a 3-amp fused jumper wire between the signal circuit of the IAT sensor and a known-good ground. Turn ON the ignition, with the engine OFF. Observe the IAT sensor temperature with a scan tool. Is the IAT sensor temperature more than 262°F (128°C)? If yes, go to step 9 . If no, go to next step.
8. Test the signal circuit of the IAT sensor for an open circuit or high resistance. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 11 .
9. Test the IAT sensor low reference circuit for high resistance or an open. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 11 .
10. Inspect for poor connections at the harness connector of the IAT sensor. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 12 .
11. Inspect for poor connections at the harness connector of the ECM. Repair the connections as necessary. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 13 .
12. Replace the MAF/IAT sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 14 .
13. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
14. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
15. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. When the vehicle is at ambient temperature the IAT sensor and ECT sensor temperatures should be relatively close to each other. See appropriate SENSOR OPERATING RANGE CHARTS article.
2. If a short to a separate 5-volt source occurs this DTC may set. If this condition exists, a continuity test to all other ECM 5-volt reference circuits will be necessary.
3. If an intermittent condition exists, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.

1. The ignition is ON.
2. DTCs P0112, P0113, P0117, P0118, P0128, P0601, P0602, P1621, P1683 are not set.
3. The vehicle has a minimum soak time of 8 hours.

If the ECM detects a temperature difference between the ECT sensor and the IAT sensor of more than 252°F (140°C) at start up; or the time spent cranking the engine, without starting is more than 10 seconds with a temperature difference between the ECT sensor and the IAT sensor of more than 36°F (20°C); or if the PCM detects a temperature between the ECT sensor and the IAT sensor of more than 36°F (20°C), then the vehicle must be driven for 5 minutes over 15 MPH. If the IAT sensor temperature decreases more than 12.6°F (7°C) then a block heater is detected and the test is aborted. If the IAT sensor temperature does not decrease, then a block heater was not detected and DTC P0116 sets.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) if a failure is detected during 2 consecutive key cycles.
2. The control module sets the DTC and records the operating conditions at the time the diagnostic failed. The failure information is stored in the scan tool Freeze Frame/Failure Records.

1. The control module turns OFF the MIL after 3 consecutive drive trips when the test has run and passed.
2. A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles. A warm-up cycle occurs when the coolant temperature has risen 40°F (22°C) from the startup coolant temperature and the engine coolant reaches a temperature that is more than 158°F (70°C) during the same ignition cycle.
3. Use a scan tool in order to clear the DTCs.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Is the cooling system low on coolant? If yes, repair and refill cooling system. If no, go to next step.
3. Turn OFF the ignition. Disconnect the ECT sensor. Connect a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the ECT sensor. Turn ON the ignition, with the engine OFF. Observe the ECT sensor temperature with a scan tool. Does the scan tool indicate that the ECT sensor temperature is more than 280°F (138°C)? If yes, go to next step. If no, go to step 5 .
4. Turn OFF the ignition. Disconnect the MAF/IAT sensor. Connect a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the IAT sensor. Turn ON the ignition, with the engine OFF. Observe the IAT sensor temperature with a scan tool. Does the scan tool indicate that the IAT sensor temperature is more than 280°F (138°C)? If yes, go to step 8 . If no, see «DIAGNOSTIC AIDS»(ref-138411-S24958773792002041200000) .
5. Turn OFF the ignition. Disconnect the ECT sensor. Connect a 3-amp fused jumper wire between the signal circuit of the ECT sensor and a known-good ground. Turn ON the ignition, with the engine OFF. Observe the ECT sensor temperature with a scan tool. Does the scan tool indicate that the ECT sensor temperature is more than 280°F (138°C)? If yes, go to next step. If no, go to step 7 .
6. Test the ECT sensor low reference circuit for a high resistance or an open. Did you find and correct the condition? If yes, go to step 12 . If no, see «DIAGNOSTIC AIDS»(ref-138411-S24958773792002041200000) .
7. Test the ECT sensor signal circuit for a high resistance or an open. Repair as necessary. After repairs, go to step 12 . If no, see «DIAGNOSTIC AIDS»(ref-138411-S24958773792002041200000) .
8. Remove the ECT sensor. Suspend the ECT sensor and a thermometer in a pan of water. Place the pan on a burner or hot plate. Test the resistance of the ECT sensor through 50-194°F (10-90°C). See appropriate SENSOR OPERATING RANGE CHARTS article. Does the resistance and temperature closely match the Temperature vs Resistance table? If yes, go to next step. If no, go to step 10 .
9. Reinstall the ECT sensor. When complete, see «DIAGNOSTIC AIDS»(ref-138411-S24958773792002041200000) .
10. Test for an intermittent and for a poor connection at the ECT sensor. Did you find and correct the condition? If yes, go to step 12 . If no, go to next step.
11. Replace the ECT sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
12. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
13. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. DTC P0116 is designed to detect an ECT sensor that is skewed high.
2. An IAT sensor that is skewed could cause this DTC to set.
3. When checking the ECT sensor, the Temperature vs Resistance table should be used in order to determine if a skewed sensor is the problem. See appropriate SENSOR OPERATING RANGE CHARTS article.

The engine run time is more than 10 seconds.

The ECT sensor temperature is more than 282°F (139°C) for more than 20 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions For Clearing MIL or DTC

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Connect a scan tool. Turn ON the ignition, with the engine OFF. Observe the ECT sensor temperature display. Does the scan tool indicate that the ECT sensor temperature is greater than 280°F (138°C)? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC reset? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-138411-S30207927902002041200000) .
4. Turn OFF the ignition. Disconnect the ECT sensor. Turn ON the ignition, with the engine OFF. With a scan tool, observe the ECT sensor temperature. Does the scan tool indicate that the ECT sensor temperature is less than -36°F (-38°C)? If yes, go to step 6 . If no, go to next step.
5. Turn OFF the ignition. Disconnect the ECM. Test the signal circuit of the ECT sensor for a short to ground. Did you find and correct the condition? If yes, go to step 10 . If no, go to step 8 .
6. Test for an intermittent and for a poor connection at the ECT sensor. Did you find and correct the condition? If yes, go to step 10 . If no, go to next step.
7. Replace the ECT sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 10 .
8. Test for an intermittent and for a poor connection at the ECM. Did you find and correct the condition? If yes, go to step 10 . If no, go to next step.
9. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
10. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
11. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. An overheating condition may cause this DTC to set.
2. After starting the engine, the ECT sensor temperature should rise steadily to about 194°F (90°C) then stabilize after the thermostat opens.
3. Use the Temperature vs. Resistance table in order to test the ECT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor could result in poor driveability concerns. See appropriate SENSOR OPERATING RANGE CHARTS article.
4. If an intermittent condition exists, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.

The engine has been running for more than 8 minutes.

The ECT sensor temperature is less than -38°F (-39°C) for 20 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Connect a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, observe the ECT sensor temperature. Does the scan tool indicate that the ECT sensor temperature is less than -36°F (-38°C)? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC reset? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-138411-S13679526022002041200000) .
4. Turn OFF the ignition. Disconnect the ECT sensor. Connect a 3-amp fused jumper wire between the signal circuit of the ECT sensor and the low reference circuit at the ECT sensor. Turn ON the ignition, with the engine OFF. With a scan tool, observe the ECT sensor temperature. Does the scan tool indicate ECT sensor temperature greater than 280°F (138°C)? If yes, go to step 8 . If no, go to next step.
5. Turn OFF the ignition. Connect a 3-amp fused jumper wire between the signal circuit of the ECT sensor and a known-good ground. Turn ON the ignition, with the engine OFF. With a scan tool, observe the ECT sensor temperature. Does the scan tool indicate that the ECT sensor temperature is greater than 280°F (138°C)? If yes, go to step 7 . If no, go to next step.
6. Test the signal circuit of the ECT sensor for the following condition: A short to a separate 5-volt circuit. A short to voltage. A high resistance. An open circuit. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 9 .
7. Test the ECT sensor reference low circuit for a high resistance or an open. Repair the circuit as necessary. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 9 .
8. Inspect for poor connections at the harness connector of the ECT sensor. Repair the connections as necessary. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 10 .
9. Turn OFF the ignition. Inspect for poor connections at the harness connector of the ECM. Repair the connections as necessary. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 11 .
10. Replace the ECT sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 12 .
11. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
12. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
13. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. If a short to a separate 5-volt source occurs, this DTC may set.
2. After starting the engine, the ECT should rise steadily, then stabilize when the thermostat opens.
3. Use the Temperature vs. Resistance table in order to test the ECT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor could result in poor driveability concerns. See appropriate SENSOR OPERATING RANGE CHARTS article.
4. If an intermittent condition exists, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.

1. DTCs P0112, P0113, P0116, P0117, or P0118 are not set.
2. The coolant temperature is 19°F (-7°C) or more.
3. The air intake temperature (IAT) is 19°F (-7°C) or more.
4. The engine has been operating less than 22 minutes.

1. The engine coolant temperature is less than 161°F (72°C).
2. The air temperature is more than 19°F (-7°C).
3. The engine has been operating more than 22 minutes.
4. The fuel burned since start up is more than 12 million mm 3 .

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Is the cooling system low on coolant? If yes, locate and repair source of coolant loss and refill system. If no, go to next step.
3. Turn OFF the ignition. Disconnect the ECT sensor. Connect a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the ECT sensor. Turn ON the ignition, with the engine OFF. With a scan tool, observe the ECT sensor temperature. Does the scan tool indicate that the ECT sensor temperature is more than 294°F (146°C)? If yes, go to step 7 . If no, go to next step.
4. Turn OFF the ignition. Connect a 3-amp fused jumper wire between the signal circuit of the ECT sensor and a known-good ground. Turn ON the ignition, with the engine OFF. With a scan tool, observe the ECT sensor temperature. Does the scan tool indicate that the ECT sensor temperature is more than 294°F (146°C)? If yes, go to next step. If no, go to step 6 .
5. Test the ECT sensor low reference circuit for a high resistance or an open. Repair the circuit as necessary. After repairs, go to step 10 .
6. Test the ECT sensor signal circuit for a high resistance or for an open. Repair the circuit as necessary. After repairs, go to step 10 .
7. Remove the ECT sensor. Suspend the ECT sensor and a thermometer in a pan of water. Place the pan on a burner or hot plate. Test the resistance of the ECT sensor through 50-194°F (10-90°C). See appropriate SENSOR OPERATING RANGE CHARTS article. Does the resistance and temperature closely match the Temperature vs Resistance table? If yes, go to next step. If no, go to step 9 .
8. Install the ECT sensor. Diagnose and repair engine not reaching normal operating temperature.
9. Replace the ECT sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
10. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
11. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. A DTC P0128 is designed to detect a faulty thermostat.
2. A skewed ECT sensor may cause a P0128 to set.
3. This DTC will not run if either the intake air or coolant temperature is too low at start up.
4. If an intermittent condition exists, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
5. Using Freeze Frame/Failure Records may aid in determining the conditions under which the failure occurred.

The ignition is ON.

The FT is above 252°F (122°C) for more than 5 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Inspect the fuel cooler located in front of the fuel tank for debris restricting the airflow or damage to the cooling fins. Inspect the fuel lines for kinks or damage. Clean or replace the above listed components as necessary. Did any of the components require a repair? If yes, go to step 11 . If no, go to next step.
3. Disconnect the air filter outlet duct to access the FRT sensor. Disconnect the FRT electrical connector. Turn ON the ignition. Probe the FRT sensor signal circuit with a Digital Multimeter (DMM) connected to ground. Is the voltage near 5 V? If yes, go to next step. If no, go to step 5 .
4. Connect a test lamp to battery voltage. Probe the low reference circuit of the FRT sensor connector. Does the test lamp illuminate? If yes, go to step 7 . If no, go to step 6 .
5. Turn OFF the ignition. Disconnect the ECM connector that contains the FRT sensor signal circuit. Inspect the signal circuit for an open or short to voltage or ground and repair the circuit as necessary. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 8 .
6. Turn OFF the ignition. Disconnect the ECM connector that contains the fuel temperature sensor low reference circuit. Inspect the FRT sensor low reference circuit and connectors for an open or high resistance and repair the circuit. Did you complete the repair? If yes, go to step 11 . If no, go to step 8 .
7. Inspect for poor connections at the FRT sensor and repair as necessary. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 9 .
8. Inspect for poor connections at the ECM and repair as necessary. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 10 .
9. Replace the FRT sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 11 .
10. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
11. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
12. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. DTCs P0112, P0113, P0182, P0183, P0500, or P1683 are not set.
2. The engine must be turned OFF for 10 hours or longer.
3. The start-up Intake Air Temperature (IAT) is more than 59°F (15°C).
4. The fuel temperature and the Engine Coolant Temperature (ECT) must be within 18°F (10°C) of each other at start-up.

1. The fuel temperature and the ECT are more than 18°F (9.8°C) of each other at start-up.
2. The IAT has dropped less than 10°F (5.3°C) after running more than 400 seconds above 15 MPH.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Allow the engine to cool to ambient temperature. Turn ON the ignition. Monitor the IAT sensor with a scan tool. Does the scan tool indicate a temperature near ambient temperature 18°F (10°C)? If yes, go to next step. If no, go to step 4 .
3. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC fail this ignition cycle? If yes, go to step 6 . If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
4. Disconnect the Mass Air Flow (MAF) sensor connector. Turn ON the ignition. Measure the voltage of the IAT signal circuit at the MAF sensor connector. Does the voltage measure near 5 V? If yes, go to next step. If no, go to step 8 .
5. Connect a test lamp to battery voltage. Probe the low reference circuit of the IAT. Does the test lamp illuminate? If yes, go to step 12 . If no, go to step 9 .
6. Disconnect the air filter outlet duct to access the fuel temperature sensor. Disconnect the fuel temperature sensor electrical connector. Turn ON the ignition. Probe the fuel temperature sensor signal circuit with a Digital Multimeter (DMM) connected to ground. Does the voltage measure near 5 V? If yes, go to next step. If no, go to step 8 .
7. Connect a test lamp to battery voltage. Probe the low reference circuit of the fuel temperature sensor connector. Does the test lamp illuminate? If yes, go to step 13 . If no, go to step 9 .
8. Turn OFF the ignition. Disconnect the Engine Control Module (ECM) connectors. Inspect the signal circuit for an open or for short to ground. Did you perform a repair? If yes, go to step 14 . If no, go to step 10 .
9. Repair the open sensor low reference circuit. Did you complete the repair? If yes, go to step 14 . If no, go to step 11 .
10. Inspect the ECM connector terminals for spreading or poor connections. Repair as necessary. Did you find and correct the condition? If yes, go to step 14 . If no, go to next step.
11. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to step 14 .
12. Replace the MAF sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 14 .
13. Replace the fuel temperature sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
14. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
15. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. The engine is running.
2. The FRT sensor is continuously monitored by the ECM.

The FRT sensor temperature is more than 248°F (120°C) for 2 seconds; or the FRT sensor voltage is less than 0.24 volt for 2 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Install a scan tool. Turn ON the ignition, with the engine OFF. Observe the fuel sensor temperature display. Does the scan tool indicate that the fuel sensor temperature is greater than 248°F (120°C)? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC reset? If yes, go to next step If no, see «DIAGNOSTIC AIDS»(ref-138411-S29962531722002041600000) .
4. Remove the air cleaner outlet duct from the air intake pipe. Disconnect the FRT sensor. Turn ON the ignition, with the engine OFF. With a scan tool, observe the FRT sensor parameter. Does the scan tool indicate that the FRT sensor is less than -22°F (-30°C)? If yes, go to step 6 . If no, go to next step.
5. Turn OFF the ignition. Disconnect the PCM. Test the signal circuit of the FRT sensor for a short to ground or a short to any low reference circuit. Did you find and correct the condition? If yes, go to step 8 . If no, go to step 7 .
6. Replace the FRT sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 8 .
7. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
8. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
9. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. After starting a cold engine, the fuel temperature should be within a few degrees of the Intake Air Temperature (IAT) sensor.
2. Use the Temperature vs. Resistance table in order to test the fuel temperature sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. See appropriate SENSOR OPERATING RANGE CHARTS article. A skewed sensor could result in poor driveability concerns.
3. If an intermittent condition exists, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.

The engine has been running for more than 8 minutes.

The FRT sensor temperature is less than -22°F (-30°C) for 2 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Install a scan tool. Turn ON the ignition, with the engine OFF. Use the scan tool in order to observe the FRT sensor temperature. Does the FRT sensor temperature measure less than -22°F (-30°C)? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as closely as possible to the Freeze Frame/Failure Records conditions. Does the DTC reset? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-138411-S21689263332002041600000) .
4. Turn OFF the ignition. Disconnect the FRT sensor. Connect a 3-amp fused jumper between the signal circuit of the FRT sensor and the low reference circuit. Turn ON the ignition, with the engine OFF. Use the scan tool in order to observe the FRT sensor temperature. Does the FRT sensor temperature measure more than 280°F (138°C)? If yes, go to step 8 . If no, go to next step.
5. Turn OFF the ignition. Connect a 3-amp fused jumper between the signal circuit of the FRT sensor and ground. Turn ON the ignition, with the engine OFF. Use the scan tool in order to observe the FRT sensor temperature. Does the FRT sensor measure more than 280°F (138°C)? If yes, go to step 7 . If no, go to next step.
6. Test the signal circuit of the FRT sensor for the following conditions: A short to voltage. A high resistance. An open circuit. Repair the circuit as necessary. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 9 .
7. Test the reference low circuit of the FRT sensor for a high resistance or an open. Repair the circuit as necessary. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 9 .
8. Inspect for poor connections at the harness connector of the FRT sensor. Repair the connections as necessary. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 10 .
9. Inspect for poor connections at the harness connector of the ECM. Repair the connections as necessary. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 11 .
10. Replace the FRT sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 12 .
11. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
12. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
13. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. If a short to a separate 5-volt source occurs, this Diagnostic Trouble Code (DTC) may set. If this is the problem, a continuity test to all other ECM circuits will be necessary in order to diagnose the specific circuit.
2. After starting a cold engine, the FRT sensor should be within a few degrees of the Intake Air Temperature (IAT) reading.
3. Use the Temperature vs Resistance table in order to test the FRT sensor at various temperature levels and in order to evaluate the possibility of a skewed sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.
4. If an intermittent condition exists, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.

1. DTCs P1635 or P1639 are not set.
2. The ignition is ON.

The ECM detects the signal circuit is less than 1.2 MPa.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Install a scan tool. Turn ON the ignition, with the engine OFF. With the scan tool, observe the Actual Fuel Rail Pressure parameter in the Powertrain, Engine Data 1 list. Does the scan tool indicate that the Actual Fuel Rail Pressure parameter is 1.2-1.9 MPa? If yes, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM. If no, go to next step.
3. Turn OFF the ignition. Disconnect the Fuel Rail Pressure (FRP) sensor. Turn ON the ignition, with the engine OFF. With a scan tool, observe the Actual Fuel Rail Pressure parameter. Does the scan tool indicate that the Actual Fuel Rail Pressure parameter is less than 175 MPa? If yes, go to next step. If no, go to step 5 .
4. Test the signal circuit of the FRP sensor for a short to ground or high resistance. Did you find and correct the condition? If yes, go to step 7 . If no, go to step 6 .
5. Replace the fuel rail pressure sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 7 .
6. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
7. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
8. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. DTC P1635 or P1639 are not set.
2. The ignition is ON.
3. The system is not in Powerdown Mode.

The ECM detects the signal circuit is more than 175 MPa.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.
3. The control module limits fuel injection and fuel rail pressure.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Turn ON the ignition, with the engine OFF. Observe the Actual Fuel Rail Pressure parameter with a scan tool. Does the scan tool indicate that the Actual Fuel Rail Pressure is 1.2-1.9 MPa? If yes, go to step 4 . If no, go to next step.
3. Disconnect the FRP sensor connector. Probe the FRP 5-volt reference circuit with a Digital Multimeter (DMM) connected to a good ground. Does the voltage measure near 5 V? If yes, go to step 5 . If no, go to next step.
4. Test the 5-volt reference circuit of the FRP sensor for a short to voltage, high resistance, or an open. Repair as necessary. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 12 .
5. Verify that the ignition is ON, with the engine OFF. Verify the FRP sensor harness connector is still disconnected. Measure the current between the FRP sensor signal circuit and ground circuit at the FRP harness connector with a DMM. Does the current measure more than 10 mA? If yes, go to step 8 . If no, go to next step.
6. Turn OFF the ignition. Disconnect the negative battery cables. Measure the resistance from the low reference circuit of the FRP sensor to a good ground. Does the resistance measure less than 5 ohms? If yes, go to next step. If no, go to step 10 .
7. Turn OFF the ignition. Connect a 3-amp fused jumper wire between the signal circuit of the FRP sensor and the low reference circuit of the FRP sensor. Turn ON the ignition, with the engine OFF. With a scan tool, observe the Actual FRP parameter. Does the scan tool indicate that the Actual FRP parameter is 0 MPa? If yes, go to step 11 . If no, go to step 9 .
8. Check for a short to voltage 12-volt or 5-volt reference on the FRP sensor signal circuit. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 14 .
9. Test the signal circuit of the FRP sensor for a high resistance or an open. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 12 .
10. Disconnect the ECM. Test the low reference circuit of the FRP sensor for a high resistance or an open. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 12 .
11. Inspect for poor connections at the harness connector of the FRP sensor. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 13 .
12. Inspect for poor connections at the harness connector of the ECM. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 14 .
13. Replace the FRP sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 15 .
14. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
15. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
16. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. DTCs U1800, and U2104 are not set.
2. The engine is running.
3. The charging system voltage is between 6-18 volts.

1. The FICM detects an incorrect current on a fuel injector circuit.
2. The condition exists for 1 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Observe the DTC information with a scan tool. Are DTCs P0201, P0204, P0206, P0207, or P0202, P0203, P0205, P0208 set? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
4. Is DTC P1261 also set? If yes, go to step 13 . If no, go to next step.
5. Turn OFF the ignition. Disconnect the FICM. Probe the ignition voltage circuit for cylinders 2, 3, 5 and 8, with a test lamp connected to battery voltage. Does the test lamp illuminate? If yes, go to next step. If no, go to step 7 .
6. Disconnect each multi-way harness connector of the fuel injectors one at a time, while monitoring the test lamp. Does the test lamp turn OFF when any of the fuel injector harness connectors are disconnected? If yes, go to step 21 . If no, go to step 33 .
7. Measure the resistance between the ignition voltage circuit and the injector command circuits for cylinders 2, 3, 5, and 8 with a DMM. Does the DMM display OL for all of the circuits? If yes, go to step 34 . If no, go to next step.
8. Does the DMM display OL for any of the circuits? If yes, go to step 23 . If no, go to next step.
9. Does the DMM display a resistance above 5 ohms for any fuel injector circuit? If yes, go to step 26 . If no, go to next step.
10. Does the DMM display a resistance below 0.3 ohms for any fuel injector circuit? If yes, go to step 27 . If no, go to next step.
11. Turn ON the ignition, with the engine OFF. Probe the ignition voltage circuit for cylinders 2, 3, 5 and 8, with a test lamp connected to ground. Does the test lamp illuminate? If yes, go to next step. If no, go to step 28 .
12. Disconnect each multi-way harness connector of the fuel injectors one at a time, while monitoring the test lamp. Does the test lamp turn OFF when any of the fuel injector harness connectors are disconnected? If yes, go to step 31 . If no, go to step 30 .
13. Turn OFF the ignition. Disconnect the FICM. Probe the ignition voltage circuit for cylinders 1, 4, 6, and 7 with a test lamp connected to battery voltage. Does the test lamp illuminate? If yes, go to next step. If no, go to step 15 .
14. Disconnect each multi-way harness connector of the fuel injectors one at a time, while monitoring the test lamp. Does the test lamp turn OFF when any of the fuel injector harness connectors are disconnected? If yes, go to step 21 . If no, go to step 33 .
15. Measure the resistance between the ignition voltage circuit and the injector command circuits for cylinders 1, 4, 6 and 7 with a DMM. Does the DMM display OL for all of the circuits? If yes, go to step 34 . If no, go to next step.
16. Does the DMM display OL for any of the circuits? If yes, go to step 23 . If no, go to next step.
17. Does the DMM display a resistance above 5 ohms for any fuel injector circuit? If yes, go to step 26 . If no, go to next step.
18. Does the DMM display a resistance below 0.3 ohms for any fuel injector circuit? If yes, go to step 27 . If no, go to next step.
19. Turn ON the ignition, with the engine OFF. Probe the ignition voltage circuit for cylinders 1, 4, 6 and 7, with a test lamp connected to ground. Does the test lamp illuminate? If yes, go to next step. If no, go to step 28 .
20. Disconnect each multi-way harness connector of the fuel injectors one at a time, while monitoring the test lamp. Does the test lamp turn OFF when any of the fuel injector harness connectors are disconnected? If yes, go to step 31 . If no, go to step 30 .
21. Probe the fuel injector command circuit, for the cylinder that caused the test lamp to turn OFF, with a test lamp connected to battery voltage. Does the test lamp illuminate? If yes, go to step 32 . If no, go to next step.
22. Test both of the fuel injector circuits, of the isolated cylinder, between the fuel injector and the multi-way connector for a short to ground. Did you find and correct the condition? If yes, go to step 37 . If no, go to step 29 .
23. Disconnect the multi-way connector of the fuel injector that displayed OL. Test the command circuit of the fuel injector, between the FICM and the multi-way connector, for the following: An open circuit. A poor connection. Did you find and correct the condition? If yes, go to step 37 . If no, go to next step.
24. Test the ignition voltage circuit of the fuel injector, between the multi-way connector and the splice, for the following: An open circuit. A poor connection. Did you find and correct the condition? If yes, go to step 37 . If no, go to next step.
25. Test both of the fuel injector circuits between the fuel injector and the multi-way connector for an open. Did you find and correct the condition? If yes, go to step 37 . If no, go to step 29 .
26. Test for the following conditions: Excessive resistance in the fuel injector circuits. Poor connections at the multi-way connector of the fuel injector. Did you find and correct the condition? If yes, go to step 37 . If no, go to step 29 .
27. Test for a short between the fuel injector ignition feed circuit, and the fuel injector command circuit. Did you find and correct the condition? If yes, go to step 37 . If no, go to step 35 .
28. Inspect for poor connections at the harness connector of the FICM. Did you find and correct the condition? If yes, go to step 37 . If no, go to step 36 .
29. Inspect for poor connections at the harness connector of the fuel injector. Did you find and correct the condition? If yes, go to step 37 . If no, go to step 35 .
30. Repair the short to voltage in the ignition voltage circuit. After repairs, go to step 37 .
31. Repair the short to voltage in the fuel injector command circuit that turned OFF the test lamp. After repairs, go to step 37 .
32. Repair the short to ground in the fuel injector command circuit. After repairs, go to step 37 .
33. Repair the short to ground in the ignition voltage circuit. After repairs, go to step 37 .
34. Repair the open in the ignition voltage circuit. After repairs, go to step 37 .
35. Replace the appropriate fuel injector. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 37 .
36. Replace the FICM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
37. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
38. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. DTC P0238 is not set.
2. The engine speed is more than 500 RPM.

The measured boost pressure is above the expected range by 35 kPa or more for 12 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
3. The ECM limits fuel delivery.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Install a scan tool. Start the engine. Monitor the Diagnostic Trouble Code (DTC) Information with the scan tool. Does the scan tool indicate that DTC P0108 is current? If yes, see «DTC P0108: BARO SENSOR CIRCUIT - HIGH PRESSURE (CA)»(ref-138411-S07459840092002041200000) . If no, go to next step.
3. Allow the engine to reach operating temperature. Turn OFF the ignition. Turn ON the ignition, with the engine OFF. Does the scan tool indicate that the difference between the boost sensor pressure and the BARO sensor pressure is more than 10 kPa? If yes, go to step 7 . If no, go to next step.
4. Turn OFF the ignition. Inspect for a ruptured or disconnected pressure hose from the charged air tube to the wastegate actuator. Did you find and correct the condition? If yes, go to step 14 . If no, go to next step.
5. Remove the hose from the wastegate actuator tube. Connect a hand vacuum pump to the actuator tube. Apply 15 in. Hg of vacuum. Does the vacuum hold? If yes, go to next step. If no, go to step 11 .
6. Apply compressed air, not exceeding 45 psi, to the actuator tube. The wastegate should begin to open near 30 psi and fully open at 45 psi. The actuator rod stroke should measure near 4 mm. Does the wastegate move to the open position? If yes, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM. If no, go to step 11 .
7. Disconnect the boost sensor electrical connector. Connect a test lamp to battery voltage. Probe the low reference circuit of the boost sensor with the test lamp. Does the test lamp illuminate? If yes, go to step 9 . If no, go to next step.
8. Test the low reference circuit of the boost sensor for high resistance or for an open. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 10 .
9. Inspect for poor connections at the boost sensor. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 12 .
10. Inspect for poor connections at the ECM. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 13 .
11. Replace the turbocharger. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 14 .
12. Replace the boost sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 14 .
13. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
14. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
15. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. DTC P0238 is not set.
2. The engine speed is less than 2700 RPM.
3. The fuel quantity is less than 70 mm 3 .
4. The total fuel quantity burned is more than 2000 mm 3 .

The measured boost pressure is above the expected range by 35 kPa or more for 12 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
3. The ECM limits fuel delivery.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Install a scan tool. Start the engine. Monitor the Diagnostic Trouble Code (DTC) Information with the scan tool. Does the scan tool indicate that DTC P0108 is current? If yes, see «DTC P0108: BARO SENSOR CIRCUIT - HIGH PRESSURE (FED)»(ref-138411-S08925119672002041500000) . If no, go to next step.
3. Allow the engine to reach operating temperature. Turn OFF the ignition. Turn ON the ignition, with the engine OFF. Does the scan tool indicate that the difference between the boost sensor pressure and the BARO sensor pressure is more than 10 kPa? If yes, go to step 7 . If no, go to next step.
4. Turn OFF the ignition. Inspect for a ruptured or disconnected pressure hose from the charged air tube to the wastegate actuator. Did you find and correct the condition? If yes, go to step 14 . If no, go to next step.
5. Remove the hose from the wastegate actuator tube. Connect a hand vacuum pump to the actuator tube. Apply 15 in. Hg of vacuum. Does the vacuum hold? If yes, go to next step. If no, go to step 11 .
6. Apply compressed air, not exceeding 45 psi, to the actuator tube. The wastegate should begin to open near 30 psi and fully open at 45 psi. The actuator rod stroke should measure near 4 mm. Does the wastegate move to the open position? If yes, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM. If no, go to step 11 .
7. Disconnect the boost sensor electrical connector. Connect a test lamp to battery voltage. Probe the low reference circuit of the boost sensor with the test lamp. Does the test lamp illuminate? If yes, go to step 9 . If no, go to next step.
8. Test the low reference circuit of the boost sensor for high resistance or for an open. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 10 .
9. Inspect for poor connections at the boost sensor. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 12 .
10. Inspect for poor connections at the ECM. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 13 .
11. Replace the turbocharger. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 14 .
12. Replace the boost sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 14 .
13. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
14. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
15. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. DTCs P0106, P0107, P0108, or P0237 are not set.
2. The engine speed is more than 500 RPM.
3. The total fuel quantity burned is more than 2000 mm 3 .
4. The Engine Coolant Temperature (ECT) is more than 140°F (60°C).

The measured boost pressure is below the expected range by 35 kPa or more for 12 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Use a scan tool in order to clear the MIL and the DTC.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Start the engine. Allow the engine to reach operating temperature. Turn OFF the ignition. Turn ON the ignition, with the engine OFF. Observe the BARO sensor and the boost sensor using the scan tool. Compare the BARO sensor pressure to the boost sensor pressure. Is the BARO sensor pressure more than the boost sensor pressure by a margin of 10 kPa or more? If yes, go to step 9 . If no, go to next step.
3. Turn OFF the ignition. Remove the boost sensor from the intake manifold. Inspect for the following conditions: A plugged sensor port. A damaged hose. A restricted hose. A disconnected hose. Did you find and correct the condition? If yes, go to step 18 . If no, go to next step.
4. Turn ON the ignition, with the engine OFF. Connect a hand vacuum pump to the sensor port. Observe the boost sensor pressure on the scan tool as you SLOWLY apply vacuum 1 in. Hg at a time up to 15 in. Hg. Each inch of vacuum should result in a 3-4 kPa drop in pressure. Does the scan tool indicate the boost sensor is operating normally? If yes, go to next step. If no, go to step 9 .
5. Disconnect the hand vacuum pump from the sensor. Does the scan tool indicate that the boost sensor pressure returns to the value observed in step 2 ? If yes, go to next step. If no, go to step 16 .
6. Inspect for the following conditions: EGR throttle valve that is stuck closed. Restriction in the air cleaner or the intake tube. Leaking charged air cooler. Leaking charged air pipes and connecting clamps and hoses. Leaking intake manifold. Did you find and correct the condition? If yes, go to step 18 . If no, go to next step.
7. Turn OFF the ignition. Remove the hose from the wastegate actuator tube. Apply compressed air, not exceeding 45 psi, to the actuator tube to open the wastegate. The wastegate should begin to open near 30 psi and be fully open at 45 psi. The actuator rod stroke should measure near 4 mm. Remove the compressed air from the actuator tube. Does the wastegate move to the fully extended position and return to the fully retracted position? If yes, go to next step. If no, go to step 15 .
8. Remove the air intake pipe. Inspect for any condition that may cause poor turbocharger performance, such as the following: Bent or broken blades. Worn shaft bearings. Oil leaks. Did you find a problem with the turbocharger? If yes, go to step 15 . If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
9. Disconnect the boost sensor electrical connector. Connect a test lamp to a good ground. Probe the 5-volt reference circuit of the boost sensor with the test lamp. Does the test lamp illuminate? If yes, go to next step. If no, go to step 11 .
10. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the boost sensor and the signal circuit of the boost sensor. Does the scan tool indicate that the pressure is more than 254 kPa? If yes, go to step 13 . If no, go to step 12 .
11. Test the 5-volt reference circuit of the boost sensor for high resistance or an open. Did you find and correct the conditions? If yes, go to step 18 . If no, go to step 14 .
12. Test the signal circuit of the boost sensor for an open. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 14 .
13. Inspect for poor connections at the boost sensor. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 16 .
14. Inspect for poor connections at the ECM. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 17 .
15. Replace the turbocharger. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 18 .
16. Replace the boost sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 18 .
17. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
18. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
19. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. DTC P0237 is not set.
2. The engine speed is between 500-2700 RPM.
3. The total fuel quantity burned is more than 2000 mm 3 .
4. The Engine Coolant Temperature (ECT) is more than 158°F (72°C).

The measured boost pressure is below the expected range by 50 kPa or more for 12 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Use a scan tool in order to clear the DTC.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Start the engine. Allow the engine to reach operating temperature. Turn OFF the ignition. Turn ON the ignition, with the engine OFF. Observe the BARO sensor and the boost sensor using the scan tool. Compare the BARO sensor pressure to the boost sensor pressure. Is the BARO sensor pressure more than the boost sensor pressure by a margin of 10 kPa or more? If yes, go to step 9 . If no, go to next step.
3. Turn OFF the ignition. Remove the boost sensor from the intake manifold. Inspect for the following conditions: A plugged sensor port. A damaged seal. Did you find and correct the condition? If yes, go to step 18 . If no, go to next step.
4. Turn ON the ignition, with the engine OFF. Connect a hand vacuum pump to the sensor port. Observe the boost sensor pressure on the scan tool as you SLOWLY apply vacuum 1 in. Hg at a time up to 15 in. Hg. Each inch of vacuum should result in a 3-4 kPa drop in pressure. Does the scan tool indicate the boost sensor is operating normally? If yes, go to next step. If no, go to step 9 .
5. Disconnect the hand vacuum pump from the sensor. Does the scan tool indicate that the boost sensor pressure returns to the value observed in step 2 ? If yes, go to next step. If no, go to step 16 .
6. Inspect for the following conditions: Restriction in the air cleaner or the intake tube. Leaking charged air cooler. Leaking charged air pipes and connecting clamps and hoses. Leaking intake manifold. Did you find and correct the condition? If yes, go to step 18 . If no, go to next step.
7. Turn OFF the ignition. Remove the hose from the wastegate actuator tube. Apply compressed air, not exceeding 45 psi, to the actuator tube to open the wastegate. The wastegate should begin to open near 30 psi and be fully open at 45 psi. The actuator rod stroke should measure near 4 mm. Remove the compressed air from the actuator tube. Does the wastegate move to the fully extended position and return to the fully retracted position? If yes, go to next step. If no, go to step 15 .
8. Remove the air intake pipe. Inspect for any condition that may cause poor turbocharger performance, such as the following: Bent or broken blades Worn shaft bearings. Oil leaks Did you find a problem with the turbocharger? If yes, go to step 15 . If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
9. Disconnect the boost sensor electrical connector. Connect a test lamp to a good ground. Probe the 5-volt reference circuit of the boost sensor with the test lamp. Does the test lamp illuminate? If yes, go to next step. If no, go to step 11 .
10. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the boost sensor and the signal circuit of the boost sensor. Does the scan tool indicate that the pressure is more than 254 kPa? If yes, go to step 13 . If no, go to step 12 .
11. Test the 5-volt reference circuit of the boost sensor for high resistance or an open. Did you find and correct the conditions? If yes, go to step 18 . If no, go to step 14 .
12. Test the signal circuit of the boost sensor for an open. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 14 .
13. Inspect for poor connections at the boost sensor. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 16 .
14. Inspect for poor connections at the ECM. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 17 .
15. Replace the turbocharger. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 18 .
16. Replace the boost sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 18 .
17. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
18. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
19. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

The ignition is ON.

The boost pressure is less than 38 kPa for 2 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
3. The ECM limits fuel delivery.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Install a scan tool. Start the engine. Monitor the Diagnostic Trouble Code (DTC) information using the scan tool. Does the scan tool indicate that DTC P1639 is current? If yes, see «DTC P1639: 5-VOLT REFERENCE 2 CIRCUIT»(ref-138411-S29319932602002041200000) . If no, go to next step.
3. With a scan tool, observe the boost sensor pressure. Does the scan tool indicate that the pressure is less than 38 kPa? If yes, go to step 5 . If no, go to next step.
4. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
5. Turn OFF the ignition. Disconnect the boost sensor electrical connector. Turn ON the ignition, with the engine OFF. Connect a test lamp to a good ground. Probe the 5-volt reference circuit of the boost sensor with a test lamp. Does the test lamp illuminate? If yes, go to next step. If no, go to step 7 .
6. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the boost sensor and the signal circuit of the boost sensor. Does the scan tool indicate that the pressure is more than 254 kPa? If yes, go to step 9 . If no, go to step 8 .
7. Test the 5-volt reference circuit of the boost sensor for high resistance or an open. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 10 .
8. Test the signal circuit of the boost sensor for a short to ground or an open. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 10 .
9. Inspect for poor connections at the boost sensor. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 11 .
10. Inspect for poor connections at the ECM. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 12 .
11. Replace the boost sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 13 .
12. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
13. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
14. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

The ignition is ON.

The boost pressure is less than 38 kPa for 2 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
3. The ECM limits fuel delivery.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Install a scan tool. Start the engine. Monitor the Diagnostic Trouble Code (DTC) information using the scan tool. Does the scan tool indicate that DTC P1639 is current? If yes, see «DTC P1639: 5-VOLT REFERENCE 2 CIRCUIT»(ref-138411-S29319932602002041200000) . If no, go to next step.
3. With a scan tool, observe the boost sensor pressure. Does the scan tool indicate that the pressure is less than 38 kPa? If yes, go to step 5 . If no, go to next step.
4. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
5. Turn OFF the ignition. Disconnect the boost sensor electrical connector. Turn ON the ignition, with the engine OFF. Connect a test lamp to a good ground. Probe the 5-volt reference circuit of the boost sensor with a test lamp. Does the test lamp illuminate? If yes, go to next step. If no, go to step 7 .
6. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the boost sensor and the signal circuit of the boost sensor. Does the scan tool indicate that the pressure is more than 254 kPa? If yes, go to step 9 . If no, go to step 8 .
7. Test the 5-volt reference circuit of the boost sensor for high resistance or an open. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 10 .
8. Test the signal circuit of the boost sensor for a short to ground or an open. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 10 .
9. Inspect for poor connections at the boost sensor. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 11 .
10. Inspect for poor connections at the ECM. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 12 .
11. Replace the boost sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 13 .
12. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
13. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
14. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

The ignition is ON

The boost pressure is more than 254 kPa for 2 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
3. The ECM limits fuel delivery.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Start the engine. Does the scan tool indicate that the boost sensor pressure is more than 254 kPa? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
4. Turn OFF the ignition. Disconnect the boost sensor electrical connector. Turn the ignition ON, with the engine OFF. Does the scan tool indicate that the boost sensor pressure is less than 38 kPa? If yes, go to next step. If no, go to step 6 .
5. Connect a test lamp to battery positive voltage. Probe the low reference circuit of the boost sensor with the test lamp. Does the test lamp illuminate? If yes, go to step 8 . If no, go to step 7 .
6. Test the signal circuit of the boost sensor for a short to voltage. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 9 .
7. Test the low reference circuit of the boost sensor for high resistance or an open. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 9 .
8. Inspect for poor connections at the boost sensor. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 10 .
9. Inspect for poor connections at the ECM. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 11 .
10. Replace the boost sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 12 .
11. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
12. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
13. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

The ignition is ON

The boost pressure is more than 254 kPa for 2 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
3. The ECM limits fuel delivery.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Start the engine. Does the scan tool indicate that the boost sensor pressure is more than 254 kPa? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
4. Turn OFF the ignition. Disconnect the boost sensor electrical connector. Turn the ignition ON, with the engine OFF. Does the scan tool indicate that the boost sensor pressure is less than 50 kPa? If yes, go to next step. If no, go to step 6 .
5. Connect a test lamp to battery positive voltage. Probe the low reference circuit of the boost sensor with the test lamp. Does the test lamp illuminate? If yes, go to step 8 . If no, go to step 7 .
6. Test the signal circuit of the boost sensor for a short to voltage. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 9 .
7. Test the low reference circuit of the boost sensor for high resistance or an open. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 9 .
8. Inspect for poor connections at the boost sensor. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 10 .
9. Inspect for poor connections at the ECM. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 11 .
10. Replace the boost sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 12 .
11. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
12. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
13. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. The engine is running at idle for more than 90 seconds.
2. The Engine Coolant Temperature (ECT) is more than 132°F (56°C).

The fuel rate adjustment for more than one cylinder exceeds an acceptable value.

Action Taken When DTC Sets (California)

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Action Taken When DTC Sets (Federal)

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

Conditions For Clearing MIL/DTC (California)

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

Conditions For Clearing MIL/DTC (Federal)

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Use a scan tool in order to clear the DTC.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Are any other DTCs set? If yes, diagnose those DTCs first. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, perform fuel injector balance test. See appropriate SYSTEM & COMPONENT TESTING article.

A misfire with no other DTCs will be caused by an engine mechanical or fuel injector problem.

1. The engine is running at idle for more than 90 seconds.
2. The Engine Coolant Temperature (ECT) is more than 132°F (56°C).

The fuel rate adjustment for a cylinder exceeds an acceptable value.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Use a scan tool in order to clear the DTC.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Are any other DTCs set? If yes, diagnose those DTCs first. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, perform fuel injector balance test. See appropriate SYSTEM & COMPONENT TESTING article.

A misfire with no other DTC's will be caused by an engine mechanical or fuel injector problem.

1. The engine is cranking or running.
2. The Camshaft Position (CMP) sensor signal is present.

The Engine Control Module (ECM) determines no signal from the CKP sensor for less than 8 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Attempt to start the engine. Does the engine start and continue to run? If yes, see «DIAGNOSTIC AIDS»(ref-138411-S31749228002002041200000) . If no, go to next step.
3. Turn OFF the ignition. Disconnect the CKP sensor harness connector. Turn ON the ignition, with the engine OFF. Connect a Digital Multimeter (DMM) between the 12-volt reference and a good ground. Does the DMM display a reading above 10 V? If yes, go to next step. If no, go to step 8 .
4. Connect a DMM between the 12-volt reference and the low reference circuit of the CKP sensor. Does the DMM display a reading above 10 V? If yes, go to next step. If no, go to step 7 .
5. Connect a DMM between the CKP sensor signal and a good ground. Does the DMM display 0 V? If yes, go to next step. If no, go to step 9 .
6. Turn OFF the ignition. Reconnect the CKP sensor. Disconnect the ECM connectors. Carefully remove the CKP signal circuit pin from the ECM connector. Reconnect the ECM connectors. Connect a DMM between the CKP signal circuit pin at the ECM and a good ground. Crank the engine and measure the DC duty cycle of the CKP signal. Does the DMM display a DC duty cycle of 45-55 percent? If yes, go to step 12 . If no, go to step 10 .
7. Test the low reference circuit for an open. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 12 .
8. Test the 12-volt reference circuit for an open or a short to ground. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 12 .
9. Test the CKP signal circuit for a short to voltage or a short to the 12-volt reference circuit. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 15 .
10. Test the CKP signal circuit for an open or a short to ground. Did you find and correct the condition? If yes, go to step 17 . If no, go to next step.
11. Check for poor connections at the CKP sensor. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 13 .
12. Inspect for poor connections at the ECM. If you find a poor connection, repair the condition as necessary. Did you complete the repair? If yes, go to step 17 . If no, go to step 15 .
13. Inspect the CKP sensor for damage or looseness. Did you find and correct the condition? If yes, go to step 17 . If no, go to next step.
14. Inspect the CKP reluctor wheel for damage or looseness. If you find the CKP reluctor wheel damaged, see appropriate article in ENGINES to repair. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 16 .
15. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to step 17 .
16. Replace the CKP sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
17. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
18. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

Note. Remove any debris from the ECM connector surfaces before servicing the ECM. Inspect the ECM connector gaskets when diagnosing or replacing the ECM. Ensure that the gaskets are installed correctly. The gaskets prevent contaminant intrusion into the ECM. For any test that requires probing the ECM or the component harness connectors, use the J 35616-A Connector Test Adapter Kit. Using this kit prevents any damage to the harness connector terminals.

The following conditions may cause this DTC to set

1. Poor connection or poor terminal tension at the sensor.
2. Crankshaft reluctor wheel damage or improper installation.
3. The sensor coming in contact with the reluctor wheel.
4. The engine running out of fuel.

Excess crankshaft end play causes the CKP sensor reluctor wheel to move out of alignment with the CKP sensor. This could result in any one of the following

1. A no-start.
2. A start and stall.
3. Erratic performance.

For an intermittent, see INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM.

The engine is cranking or running.

The Engine Control Module (ECM) determines that the CKP sensor signal is out of range for less than 2 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC as specified in the supporting text or as closely as possible to the Freeze Frame/Failure Records conditions. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-138411-S12157286862002041200000) .
3. Visually and physically inspect all circuits going to the CKP sensor for the following: Routed to close to secondary ignition wires or components. Routed to close to after-market add-on electrical equipment. Routed to close to solenoids, relays, and motors. If you find incorrect routing, correct the harness routing. Did you find and correct the condition? If yes, go to step 9 . If no, go to next step.
4. Inspect for poor connections at the CKP sensor. If you find a poor connection, repair the terminal as necessary. Did you complete the repair? If yes, go to step 9 . If no, go to next step.
5. Test for poor connections at the ECM for the CKP sensor circuits. If you find a poor connection repair the terminal as necessary. Did you complete the repair? If yes, go to step 9 . If no, go to next step.
6. Remove the CKP sensor. Inspect the CKP sensor for signs of damage. If you find the CKP sensor to be damaged, replace sensor. Did you find and correct the condition? If yes, go to step 9 . If no, go to next step.
7. Inspect the CKP reluctor wheel for damage. If you find the CKP reluctor wheel is damaged, see appropriate article in ENGINES to repair. Did you find and correct the condition? If yes, go to step 9 . If no, go to next step.
8. Replace the CKP sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
9. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
10. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. An intermittent CKP sensor signal may cause DTC P0336 to set. Wiggle the wiring harness with the engine running and observe the Cam Signal Missed parameter of the scan tool. If the parameter indicates anything other than 0, there is an intermittent condition. See «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. A short from the 12-volt reference circuit to the Low reference circuit internally in the Camshaft Position (CMP) or Crankshaft Position (CKP) sensor can cause all three DTCs P0336, P0340, and P1345 to set.

1. The ignition is ON.
2. The engine is turning faster than 50 RPM.

The ECM does not see a CMP sensor signal for more than 2 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Attempt to start the engine. Does the engine start and run? If yes, see «DIAGNOSTIC AIDS»(ref-138411-S17200171512002041700000) . If no, go to next step.
3. Turn OFF the ignition. Disconnect the CMP sensor. Turn ON the ignition, with the engine OFF. Connect a Digital Multimeter (DMM) between the 12-volt reference and the low reference circuit of the CMP sensor. Does the DMM display a reading above 10 V? If yes, go to step 5 . If no, go to next step.
4. Connect a DMM between the 12-volt reference and chassis ground. Does the DMM display a reading above 10 V? If yes, go to step 7 . If no, go to step 8 .
5. Connect a DMM between the CMP sensor signal and a good ground. Does the DMM display 0 V? If yes, go to next step. If no, go to step 9 .
6. Turn OFF the ignition. Reconnect the CMP sensor. Disconnect the ECM connector C1. Carefully remove the CMP signal circuit pin from the ECM connector. Reconnect the ECM connector. Connect a DMM between the CMP signal circuit pin at the ECM and a good ground. Crank the engine and measure the DC duty cycle of the CMP signal. Does the DMM display a DC duty cycle of 45-55 percent? If yes, go to step 12 . If no, go to step 10 .
7. Test the low reference circuit for an open. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 12 .
8. Test the 12-volt reference circuit for an open or a short to ground. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 12 .
9. Test the CMP signal circuit for a short to voltage or a short to the 12-volt reference circuit. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 14 .
10. Test the CMP signal circuit for an open or a short to ground. Did you find and correct the condition? If yes, go to step 15 . If no, go to next step.
11. Check for poor connections at the CMP sensor. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 13 .
12. Check for poor connections at the ECM. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 14 .
13. Replace the CMP sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 15 .
14. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
15. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
16. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. An intermittent CMP sensor signal may cause DTC P0340 to set. Wiggle the wiring harness with the engine running and observe the Cam Signal Missed parameter of the scan tool. If the parameter indicates anything other than 0, there is an intermittent condition. See «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. A short from the 12-volt reference circuit to the low reference circuit internally in the Camshaft Position (CMP) or Crankshaft Position (CKP) sensor can cause all three DTCs P0336, P0340, and P1345 to set.
3. If the CMP sensor signal is lost while running, the engine will operate normally. If the CMP sensor signal is not present on start-up, the engine will not start.

1. The ignition is ON.
2. The engine is turning faster than 50 RPM.

The Engine Control Module (ECM) determines that the CMP sensor signal is out of range for less than 2 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as closely as possible to the Freeze Frame/Failure Records conditions. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-138411-S21181020902002041200000) .
3. Visually and physically inspect all circuits going to the CMP sensor for the following: Being routed too close to secondary ignition wires or components. Being routed too close to after-market add-on electrical equipment. Being routed too close to solenoids, relays, and motors. If you find incorrect routing, correct the harness routing. Did you find and correct the condition? If yes, go to step 9 . If no, go to next step.
4. Inspect for poor connections at the CMP sensor. If you find a poor connection, repair the terminal as necessary. Did you find and correct the condition? If yes, go to step 9 . If no, go to next step.
5. Inspect for poor connections at the ECM for the CMP sensor circuits. If you find a poor connection, repair the terminal as necessary. Did you find and correct the condition? If yes, go to step 9 . If no, go to next step.
6. Remove the CMP sensor. Inspect the CMP sensor for signs of damage. Did you find and correct the condition? If yes, go to step 9 . If no, go to next step.
7. Inspect the CMP reluctor wheel for damage. If the CMP reluctor wheel is damaged, repair as necessary. See appropriate article in ENGINES. Did you find and correct the condition? If yes, go to step 9 . If no, go to next step.
8. Replace the CMP sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
9. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
10. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. An intermittent CMP sensor signal may cause DTC P0341 to set. Wiggle the wiring harness with the engine running and observe the Cam Signal Missed parameter of the scan tool. If the parameter indicates anything other than 0, there is an intermittent condition. See «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. A short from the 12-volt reference circuit to the low reference circuit internally in the Camshaft Position (CMP) or Crankshaft Position (CKP) sensor can cause all three DTCs P0336, P0340, P0341, and P1345 to set.
3. If the CMP sensor signal is lost while running, the engine will operate normally. If the CMP sensor signal is not present on start-up, the engine will not start.

The engine is cranking or running.

The FICM does not receive a crank signal, but does receive injection requests from the ECM; or the FICM receives an invalid crank signal from the ECM.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Crank the engine. Use the scan tool to observe the Specific DTC information for the DTC that was set. Does the scan tool display Last Test Failed? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
3. Turn OFF the ignition. Disconnect the Fuel Injection Control Module (FICM) harness connector containing the engine speed signal circuit. Measure the voltage from the engine speed signal circuit at the FICM harness connector to a good ground using an adapter terminal and a Digital Multimeter (DMM). Crank the engine. Does the voltage measure 4-5 V? If yes, go to next step. If no, go to step 5 .
4. With the DMM still connected, measure the current from the engine speed signal circuit to a good ground. Does the current measure less than 10 mA? If yes, go to step 10 . If no, go to next step.
5. Does the voltage measure above 4-5 V? If yes, go to step 7 . If no, go to step 8 .
6. Repair the short to reference voltage on the engine speed signal circuit. After repairs, go to step 13 .
7. Test for a short to battery voltage, ignition voltage, or either 5-volt reference on the engine speed signal circuit. Repair as necessary. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 11 .
8. Test the engine speed signal circuit for an open or a short to ground. Repair as necessary. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 11 .
9. Inspect for poor connections at the FICM. Repair as necessary. Did you find and correct the condition? If yes, go to step 13 . If no, go to next step.
10. Replace the fuel injection control module. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 13 .
11. Inspect for poor connections at the ECM. Repair as necessary. Did you find and correct the condition? If yes, go to step 13 . If no, go to next step.
12. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
13. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
14. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

A missing high resolution signal will cause a no-start condition.

The ignition is ON.

The glow plugs are commanded OFF and the glow plug feedback is more than 2 volts; or the glow plugs are commanded on and the glow plug feedback is not between 5 volts and 6.2 volts.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. If this DTC set after an ECM reflash; Connect a scan tool. Turn ON the ignition, with the engine OFF. Observe the Glow Plug System Type parameter on the scan tool. Does the scan tool display the Glow Plug System Type as California? If yes, go to next step. If no, see «DTC P0380: GLOW PLUG CIRCUIT PERFORMANCE (FED)»(ref-138411-S08898743252002041700000) .
3. Did DTC P0489, P0540, P2141, and P2144 also set? If yes, go to step 16 . If no, go to next step.
4. Connect a scan tool. Turn ON the ignition, with the engine OFF. Use the scan tool in order to command the glow plugs ON and OFF. Observe the glow plug feedback parameter on the scan tool. Does the scan tool display the glow plug feedback parameter as 5.0-5.6 V? If yes, go to step 8 . If no, go to next step.
5. Does the scan tool display a glow plug voltage more than 5.6 V? If yes, go to step 22 . If no, go to next step.
6. Does the scan tool display a glow plug voltage more than 0.70 V? If yes, go to step 11 . If no, go to next step.
7. Turn ON the ignition, with the engine OFF. Touch the battery feed stud on the glow plug relay with an unpowered test lamp connected to ground. Does the test lamp illuminate? If yes, go to step 9 . If no, go to step 25 .
8. The DTC is intermittent. If no additional DTCs are stored, see «DIAGNOSTIC AIDS»(ref-138411-S16666636402002041700000) . If any additional DTCs were stored, refer to those tables. Were there any additional DTCs stored? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no
9. Disconnect the glow plug relay middle connector. Turn ON the ignition, with the engine OFF. With an unpowered test lamp connected to ground, probe the glow plug relay harness ignition feed circuit. Does the test lamp illuminate? If yes, go to next step. If no, go to step 17 .
10. Turn ON the ignition, with the engine OFF. Connect an unpowered test lamp to battery voltage, probe the glow plug relay harness ground circuit. Does the test lamp illuminate? If yes, go to next step. If no, go to step 18 .
11. Turn ON the ignition, with the engine OFF. Verify that the glow plug relay harness is disconnected. With an unpowered test lamp connected to ground, probe the glow plug relay control circuit at the glow plug relay harness connector. Use a scan tool in order to command the glow plugs ON and OFF. Does the test lamp illuminate with the scan tool command ON? If yes, go to step 13 . If no, go to next step.
12. Does the test lamp illuminate all of the time? If yes, go to step 24 . If no, go to step 19 .
13. Verify that the glow plug relay is still disconnected. Turn ON the ignition, with the engine OFF. Using the J 35616-A Connector Test Adapter Kit, jumper the glow plug control circuit to the glow plug signal circuit scan tool. Use a scan tool in order to command the glow plugs ON. Observe the scan tool while the glow plugs are commanded ON. Does the glow plug parameter voltage measure near Battery Voltage? If yes, go to next step. If no, go to step 21 .
14. Turn OFF the ignition. Disconnect the right and left bank glow plug output circuit connectors at the glow plug relay. With an unpowered test lamp connected to battery voltage, probe each circuit. Does the test lamp illuminate for each circuit? If yes, go to step 27 . If no, go to next step.
15. Turn OFF the ignition. Disconnect each glow plug connector at the glow plug that did not illuminate the test lamp. With an unpowered test lamp connected to battery voltage, probe the terminal on the glow plug. Does each glow plug illuminate the test lamp? If yes, go to step 27 . If no, go to step 26 .
16. Repair the open or short to ground between the fuel heater fuse and the supplied components. After repairs, go to step 30 .
17. Repair an open in the glow plug relay ignition 1 voltage circuit. After repairs, go to step 30 .
18. Repair the open circuit or poor connections in the glow plug relay harness ground circuit. After repairs, go to step 30 .
19. Inspect the glow plug relay control circuit for an open or short to ground and repair as necessary. Did you find and correct the condition? If yes, go to step 30 . If no, go to next step.
20. Inspect the glow plug relay control circuit for a proper connection at the ECM and replace the terminal if necessary. Did you find and correct the condition? If yes, go to step 30 . If no, go to step 29 .
21. Inspect the glow plug relay signal circuit for an open or short to ground and repair as necessary. Did you find and correct the condition? If yes, go to step 30 . If no, go to step 28 .
22. Inspect the glow plug relay signal circuit for a proper connection at the ECM and replace the terminal if necessary. Did you find an improper connection and make the necessary replacement? If yes, go to step 30 . If no, go to next step.
23. Inspect for a short to voltage in the glow plug relay signal circuit and repair as necessary. Did you find the improper condition? If yes, go to step 30 . If no, go to step 27 .
24. Inspect for a short to voltage in the glow plug control circuit and repair as necessary. Did you find the improper condition? If yes, go to step 30 . If no, go to step 29 .
25. Repair the open or poor connection on the battery voltage circuit. After repairs, go to step 30 .
26. Replace any glow plug that did not illuminate the test lamp. After repairs, go to step 30 .
27. Inspect for an open or poor connection in the glow plug harness. Did you find and correction the condition? If yes, go to step 30 . If no, go to next step.
28. Replace the glow plug relay. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 30 .
29. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
30. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
31. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

If the glow plug relay is stuck in the ON position, check for proper operation of the glow plugs. When the glow plugs are commanded ON by the scan tool, an internal Engine Control Module (ECM) timer protects the glow plugs from damage by cycling them ON for 3 seconds and the OFF for 12 seconds. The glow plug relay battery feed wire nut at the relay should be tested for proper torque. The California glow plug system will send the following voltages, or signals to the ECM. See GLOW PLUG VOLTAGE table.

GLOW PLUG VOLTAGE

An intermittent may be caused by the following

1. Poor connections, terminal tension.
2. Rubbed-through wire insulation.
3. Broken wire inside the insulation.
4. A short to battery positive voltage on the glow plug relay control circuit.

The ignition switch in the ON position.

The ECM has commanded glow plugs ON and the glow plug signal voltage is less than 4 volts; or the ECM has commanded glow plugs OFF and the glow plug signal voltage is more than 4 volts.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Confirm that the glow plugs are commanded OFF with the scan tool. Does the scan tool display glow plug feedback signal voltage present all the time? If yes, go to step 9 . If no, go to next step.
3. Turn ON the ignition, with the engine OFF. Disconnect the glow plug relay. Probe the glow plug relay control circuit at the glow plug relay harness connector with a Digital Multimeter (DMM) connected to ground. Command the glow plug relay ON with a scan tool. Does the voltage measure near battery voltage? If yes, go to next step. If no, go to step 8 .
4. Turn ON the ignition, with the engine OFF. Probe the battery positive voltage circuit of the glow plug relay with a test lamp that is connected to a good ground. Does the test lamp illuminate? If yes, go to next step. If no, go to step 12 .
5. Probe the ground circuit of the glow plug relay with a test lamp connected to battery voltage. Does the test lamp illuminate? If yes, go to next step. If no, go to step 13 .
6. Reconnect the glow plug relay. Turn ON the ignition, with the engine OFF. Probe the glow plug signal circuit at the glow plug relay connector with a test lamp connected to a good ground. Command the glow plug relay ON and OFF with a scan tool. Does the test lamp illuminate when the scan tool commands the glow plugs ON? If yes, go to next step. If no, go to step 17 .
7. Turn OFF the ignition. Disconnect the ECM. Test the glow plug signal circuit for an open or short to ground. Did you find a problem? If yes, go to step 14 . If no, go to step 18 .
8. Test the glow plug relay control circuit for an open or short to ground. If the glow plug relay control circuit is open or shorted to ground, repair as necessary. Did you find and correct the condition? If yes, go to step 21 . If no, go to step 18 .
9. Disconnect the glow plug relay connector. Turn ON the ignition, with the engine OFF. Probe the glow plug relay control circuit with a test lamp connected to a good ground. Does the test lamp illuminate all of the time? If yes, go to next step. If no, go to step 11 .
10. Turn OFF the ignition. Disconnect the ECM. Turn ON the ignition. Probe the glow plug relay control circuit with a test lamp connected to a good ground. Does the test lamp illuminate? If yes, go to step 16 . If no, go to step 20 .
11. Probe the glow plug signal circuit with a test lamp connected to a good ground. Does the test lamp illuminate? If yes, go to step 15 . If no, go to step 19 .
12. Repair the open or short to ground in the battery positive voltage circuit to the glow plug relay. After repairs, go to step 21 .
13. Repair the open in the glow plug relay ground circuit. After repairs, go to step 21 .
14. Repair the open or short to ground in the glow plug signal circuit. After repairs, go to step 21 .
15. Repair the short to voltage in the glow plug signal circuit. After repairs, go to step 21 .
16. Repair the short to voltage in glow plug relay control circuit. After repairs, go to step 21 .
17. Check for poor connections at the glow plug relay. Repair as necessary. Did you find and correct the condition? If yes, go to step 21 . If no, go to step 19 .
18. Check for poor connections at the ECM. Repair as necessary. Did you find and correct the condition? If yes, go to step 21 . If no, go to step 20 .
19. Replace the glow plug relay. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 21 .
20. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
21. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
22. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

If the glow plug relay is stuck in the ON position, check for proper operation of the glow plugs, perform Glow Plug System Diagnosis. See appropriate SYSTEM & COMPONENT TESTING article. When glow plugs are commanded ON by the scan tool, an internal ECM timer protects the glow plugs from damage by cycling them ON for 3 seconds and then OFF for 12 seconds.

The glow plug output feed wire nut and battery feed wire nut at the relay should be checked for proper torque, 44 INCH lbs. (5 N.m) and for corrosion.

An intermittent may be caused by the following

1. Poor connections.
2. Rubbed through wire insulation.
3. Broken wire inside the insulation.

1. DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0405, P0406, P0489, P0490, P0500, P1639, P2142, P2144, and P2145 are not set.
2. The PCM is not in the Reduced Engine Power mode.
3. The Engine Run Time parameter is more than 5 seconds.
4. The BARO parameter is more than 72 kPa.
5. The Engine Speed parameter is between 610-820 RPM and is steady within 50 RPM for more than 3 seconds.
6. The ECT Sensor parameter is between 140-212°F (60-100°C).
7. The Calculated Fuel Rate parameter is between 3-20 mm 3 .
8. The Power Take Off (PTO) is disabled. (If equipped).
9. The IAT Sensor parameter is more than 32°F (0°C).
10. The APP Indicated Angle parameter is less than 1 percent.
11. The Ignition 1 Signal parameter is between 11-18 volts.
12. The Vehicle Speed Sensor parameter is less than 0.25 MPH.
13. All of the above conditions are met for more than 3 seconds.

1. The PCM detects a calibrated difference between the expected MAF rate and the actual MAF rate during EGR system operation.
2. The PCM detects no difference between the expected EGR vacuum sensor signal and the actual EGR vacuum sensor signal.
3. The above conditions are met for more than 4 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Is DTC P0404, P0405, P0406, P0489, P0490, P1404, P2141, P2142, P2144, or P2145 also set? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, go to next step.
3. Disconnect the EGR valve vacuum hose. Install a vacuum gauge on the vacuum hose. Start and idle the engine. Command the EGR System Seal to 100 percent with a scan tool. Is the vacuum more than 15 in. Hg? If yes, go to next step. If no, go to step 6 .
4. Connect a vacuum pump to the EGR valve. Apply 15 in. Hg. Does the EGR valve hold steady vacuum? If yes, go to step 8 . If no, go to next step.
5. Test for the following conditions: Restricted vacuum hose between the vacuum pump and the EGR throttle valve vacuum control solenoid. A restricted EGR throttle valve vacuum control solenoid. Plugged EGR ports. Exhaust system leaks. Exhaust system restrictions. Exhaust system modifications. Did you find and correct the condition? If yes, go to step 9 . If no, see «DIAGNOSTIC AIDS»(ref-138411-S02263577672002041200000) .
6. Repair the leak or restriction in the vacuum hose between the EGR valve and the vacuum sensor. After repairs, go to step 8 .
7. Replace the EGR valve. See appropriate REMOVAL, OVERHAUL & INSTALLATION. After repairs, go to next step.
8. Select the Diagnostic Trouble Code (DTC) option and the Clear DTC option using the scan tool. Idle the engine at the normal operating temperature. Select the Diagnostic Trouble Code (DTC) option and the Specific DTC option, then enter the DTC number using the scan tool. Operate the vehicle within the Conditions for Running this DTC, if applicable. Does the scan tool indicate that this test failed? If yes, go to step 2 . If no, go to next step.
9. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

Inspect the MAF sensor for proper operation. An inaccurate MAF sensor signal may cause this DTC to set.

If the condition is determined to be intermittent, see INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM.

1. DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0405, P0406, P0489, P0490, P0500, P1639, P2142, P2144, and P2145 are not set.
2. The EGR valve vacuum control solenoid has been commanded to more than 70 percent.
3. The PCM is not in the Reduced Engine Power mode.
4. The Engine Run Time parameter is more than 5 seconds.
5. The BARO parameter is more than 72 kPa.
6. The Engine Speed parameter is between 610-820 RPM and is steady within 50 RPM for more than 3 seconds.
7. The ECT Sensor parameter is between 140-212°F (60-100°C).
8. The Calculated Fuel Rate parameter is between 3-20 mm 3 .
9. The Power Take Off (PTO) is disabled. (If equipped).
10. The IAT Sensor parameter is more than 32°F (0°C).
11. The APP Indicated Angle parameter is less than 1 percent.
12. The Ignition 1 Signal parameter is between 11-18 volts.
13. The Vehicle Speed Sensor parameter is less than 0.25 MPH.
14. All of the above conditions are met for more than 3 seconds.

1. The ECM detects a lower than desired EGR vacuum sensor signal and a higher than expected MAF rate.
2. The above condition is met for more than 8 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Start the engine. Command the EGR Solenoid to 100 percent with the scan tool. Observe the EGR Vacuum Sensor parameter with a scan tool. Is the vacuum less than 35 kPa? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition cycle? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-138411-S28385195732002041200000) .
4. Disconnect the vacuum line from the EGR vacuum sensor. Connect a vacuum gauge to the vacuum line. Start the engine. Allow the engine to reach operating temperature. Command the EGR Solenoid to 100 percent with a scan tool. Observe the EGR Vacuum Sensor parameter with a scan tool. Does the vacuum measure more than 15 in. Hg? If yes, go to step 8 . If no, go to next step.
5. Turn OFF the engine. Disconnect the vacuum line from the vacuum pump. Install a vacuum gauge on the vacuum pump with a short piece of vacuum line. Start the engine. Observe the vacuum gauge. Does the vacuum measure more than 15 in. Hg? If yes, go to next step. If no, go to step 7 .
6. Repair the restricted or leaking vacuum line between the EGR throttle valve vacuum control solenoid and the vacuum pump. After repairs, go to step 9 .
7. Replace the vacuum pump. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 9 .
8. Replace the EGR vacuum sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
9. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
10. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

Inspect for the following conditions

1. Vacuum leaks and restrictions in the EGR control system vacuum lines.
2. Vacuum leaks and restrictions in the EGR control system components.
3. A stuck closed EGR vacuum vent solenoid.
4. A stuck closed EGR valve vacuum control solenoid.
5. Proper vacuum line connections.

1. DTC P0101, P0489, or P1639 are not set.
2. The ignition is ON.
3. The Ignition 1 Signal parameter is between 11-18 volts.

1. The EGR Vacuum Sensor parameter is less than 19 kPa.
2. The above conditions are met for more than 5 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Start the engine. Observe the EGR Vacuum Sensor parameter with a scan tool. Is the EGR Vacuum Sensor parameter more than 18 kPa? If yes, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM. If no, go to next step.
3. Turn OFF the ignition. Disconnect the EGR vacuum sensor. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the EGR vacuum sensor and the EGR vacuum sensor signal circuit. Turn ON the ignition, with the engine OFF. Observe the EGR Vacuum Sensor parameter with a scan tool. Does the vacuum measure more than 158 kPa? If yes, go to step 6 . If no, go to next step.
4. Test the 5-volt reference circuit of the EGR vacuum sensor for a short to ground, high resistance, or an open. Did you find and correct the condition? If yes, go to step 10 . If no, go to next step.
5. Test the EGR vacuum sensor signal circuit for a short to ground, a high resistance, or an open. Did you find and correct the condition? If yes, go to step 10 . If no, go to step 7 .
6. Test for an intermittent and for a poor connection at the EGR vacuum sensor. Did you find and correct the condition? If yes, go to step 10 . If no, go to step 8 .
7. Test for an intermittent and for a poor connection at the ECM. Did you find and correct the condition? If yes, go to step 10 . If no, go to step 9 .
8. Replace the EGR vacuum sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 10 .
9. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
10. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC as specified in the supporting text. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
11. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. DTC P1639 is not set.
2. The ignition is ON.
3. The Ignition 1 Signal parameter is between 11-18 volts.

1. The EGR Vacuum Sensor parameter is more than 158 kPa.
2. The above conditions are met for more than 5 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Is DTC P1639 also set? If yes, see «DTC P1639: 5-VOLT REFERENCE 2 CIRCUIT»(ref-138411-S29319932602002041200000) . If no, go to next step.
3. Start the engine. Command the EGR Solenoid to 100 percent with a scan tool. Observe the EGR Vacuum Sensor parameter with a scan tool. Is the EGR Vacuum Sensor parameter more than 158 kPa? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
4. Turn OFF the ignition. Disconnect the EGR vacuum sensor harness connector. Turn ON the ignition, with the engine OFF. Connect a test lamp between the low reference circuit of the EGR vacuum sensor and battery voltage. Does the test lamp illuminate? If yes, go to step 6 . If no, go to next step.
5. Test the low reference circuit of the EGR vacuum sensor for high resistance or an open. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 7 .
6. Disconnect the EGR vacuum sensor harness connector. With a scan tool, observe the EGR vacuum sensor parameter. Does the scan tool indicate that the EGR Vacuum Sensor parameter is less than 18 kPa? If yes, go to step 8 . If no, go to next step.
7. Test the signal circuit of the EGR vacuum sensor for a short to voltage. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 9 .
8. Test for an intermittent and for a poor connection at the EGR vacuum sensor. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 10 .
9. Test for an intermittent and for a poor connection at the ECM. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 11 .
10. Replace the EGR vacuum sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 12 .
11. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
12. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC as specified in the supporting text. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
13. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. The Engine Run Time parameter is more than 0.5 second.
2. The Ignition 1 Signal parameter is between 11-18 volts.
3. The EGR Solenoid Command parameter is less than 71 percent.

The ECM detects a low voltage condition on the EGR valve solenoid control circuit for more than 2 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Turn ON the ignition, with the engine OFF. Command the EGR Solenoid to 50 percent with a scan tool. Does the EGR valve vacuum control solenoid click continuously when commanded with a scan tool? If yes, go to next step. If no, go to step 4 .
3. Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition cycle? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
4. Inspect the Fuel HT Fuse. Is the fuse open? If yes, go to next step. If no, go to step 6 .
5. Disconnect the EGR valve vacuum control solenoid. Test the Ignition 1 voltage circuit for a short to ground. If a short to ground is found then replace the fuse. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 10 .
6. Disconnect the EGR valve vacuum control solenoid. Connect a test lamp between the ignition 1 voltage circuit of the EGR valve vacuum control solenoid and a good ground. Turn ON the ignition with the engine OFF. Does the test lamp illuminate? If yes, go to next step. If no, go to step 8 .
7. Connect a test lamp between the Ignition 1 voltage circuit of the EGR valve vacuum control solenoid and the control circuit of the EGR valve vacuum control solenoid. Command the EGR solenoid to 100 percent with a scan tool. Does the test lamp illuminate? If yes, go to step 10 . If no, go to step 9 .
8. Repair the open ignition 1 voltage circuit. After repairs, go to step 14 .
9. Test the control circuit of the EGR valve vacuum control solenoid for an open or high resistance. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 11 .
10. Test for an intermittent and for a poor connection at the EGR valve vacuum control solenoid. Replace the fuse if necessary. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 12 .
11. Test for an intermittent and for a poor connection at the ECM. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 13 .
12. Replace the EGR valve vacuum control solenoid. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Replace the fuse if necessary. After repairs, go to step 14 .
13. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
14. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC as specified in the supporting text. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
15. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. The Engine Run Time parameter is more than 0.5 second.
2. The Ignition 1 Signal parameter is between 11-18 volts.
3. The EGR Solenoid Command parameter has been commanded to more than 10 percent.

The ECM detects a high voltage condition on the EGR valve vacuum solenoid control circuit for more than 2 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Turn ON the ignition, with the engine OFF. Command the EGR Solenoid to 50 percent with a scan tool. Does the EGR valve vacuum control solenoid click continuously when commanded with a scan tool? If yes, go to next step. If no, go to step 4 .
3. Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition cycle? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
4. Disconnect the EGR valve vacuum control solenoid. Connect a test lamp between the control circuit of the EGR valve vacuum control solenoid and a good ground. Start the engine. Does the test lamp illuminate? If yes, go to next step. If no, go to step 6 .
5. Test for a short to voltage on the control circuit of the EGR valve vacuum control solenoid. Did you find and correct the condition? If yes, go to step 10 . If no, go to step 7 .
6. Test for an intermittent and for a poor connection at the EGR valve vacuum control solenoid. Did you find and correct the condition? If yes, go to step 10 . If no, go to step 8 .
7. Test for an intermittent and for a poor connection at the ECM. Did you find and correct the condition? If yes, go to step 10 . If no, go to step 9 .
8. Replace the EGR valve vacuum control solenoid. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 10 .
9. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
10. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC as specified in the supporting text. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
11. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. Engine Running.
2. The ECT is greater than 77°F (25°C).

1. If the ECM detects a difference in vehicle speed with the VSS of more than 5 MPH, then DTC P0500 is set.
2. No vehicle speed with engine RPM greater than 1000 RPM and engine torque more than 221 ft. lbs. (300 N.m).

1. The ECM illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive drive trip that the diagnostic runs.
2. The ECM disables cruise control.
3. The ECM records the operating conditions when the Conditions for Setting DTC are met. The ECM stores this information as Freeze Frame and Failure Records.
4. The ECM stores DTC P0500 in ECM history.

1. The ECM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
2. A scan tool can clear the MIL/DTC.
3. The ECM clears the DTC from ECM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
4. The ECM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the ECM.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Install a scan tool. Turn ON the ignition, with the engine OFF. Using the Clear Info function erases stored DTCs in both the TCM and ECM. Record the DTC Freeze Frame and Failure Records. Is there a DTC P0721 or P0722 present? If yes, see appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS. If no, go to next step.
3. Install a scan tool. Turn ON the ignition, with the engine OFF. Using the Clear Info function erases stored DTCs in both the ECM and TCM. Record the DTC Freeze Frame and Failure Records. Clear the DTC. Raise and support the vehicle. Start and idle the engine. Turn OFF the traction control system, if equipped. Select and monitor Engine Data 1/Vehicle Speed on the scan tool. Place the transmission into Drive. With the drive wheels rotating, slowly increase the engine speed. Does Vehicle Speed on the scan tool increase with wheel speed? If yes, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM. If no, go to next step.
4. Turn OFF the engine. Disconnect connector C2 at the ECM. Turn the ignition to the ON position. Using the Digital Multimeter (DMM) and the J 35616-A GM Terminal Test Kit, test the signal circuit (CKT 400) for voltage between pin No. 21 and ground. Is the circuit voltage -5.0 V to 4.0 V or +5.0 V to 4.0 V? If yes, go to step 7 . If no, go to next step.
5. Turn OFF the ignition. Test the signal circuit (CKT 400) between the TCM and ECM for the following: An open circuit. A short to ground. Did you find and correct a condition? If yes, go to step 8 . If no, go to next step.
6. Replace the TCM. After repairs, go to step 8 .
7. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
8. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. No Manifold Absolute Pressure (MAP) sensor DTCs P0106, P0107 or P0108.
2. No Throttle Position (TP) or Accelerator Pedal Position (APP) sensor DTCs P0121, P0122, P0123, P1120, P1125, P1220, P1221, P1514, P1515, P1516, P1517, or P1518.
3. No crankshaft position sensor DTCs P0335 or P0336.
4. The ECT is greater than 95°F (35°C).
5. The TP sensor angle is 5-100 percent.
6. The engine speed is greater than 1000 RPM.
7. The turbo boost pressure is 6-15 psi (40-100 kPa).
8. All of the above conditions are met for two seconds.

The ECM detects no vehicle speed for 100 seconds.

1. The ECM illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive drive trip that the diagnostic runs and fails.
2. Cruise Control is disabled.
3. The ECM records the operating conditions at the time when the Conditions for Setting DTC are met. The ECM stores this information as Freeze Frame and Failure Records.
4. The ECM stores P0500 in ECM history.

1. The ECM turns OFF the MIL after three consecutive ignition cycles in which the diagnostic test runs and passes.
2. The ECM cancels the DTC default actions when the fault no longer exists and the DTC passes.
3. The ECM clears the DTC from ECM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
4. A scan tool can clear the MIL/DTC.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Install a scan tool. Turn ON the ignition with the engine OFF. Record the DTC Freeze Frame and Failure Records. Clear the DTC. Raise the drive wheels. Start the engine. Allow the engine to idle in gear. Does the scan tool display vehicle speed above 0 MPH? If yes, go to next step. If no, go to step 4 .
3. Turn OFF the ignition. Turn ON the ignition with the engine OFF. Review the Freeze Frame data and note the parameters. Start the engine. Operate the vehicle within the Freeze Frame conditions and Conditions for Running DTC. Does the scan tool display vehicle speed above 0 MPH? If yes, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM. If no, go to next step.
4. Verify that the latest calibration is installed in the ECM. Update the ECM with the latest calibration as necessary. Did the ECM require a calibration update? If yes, go to step 14 . If no, go to next step.
5. Turn OFF the ignition. Disconnect the ECM. Measure the resistance between terminals C2-20 and C2-21. Is the resistance 966-2200 ohms? If yes, go to step 7 . If no, go to next step.
6. Test the VSS high signal circuit and the VSS low signal circuit for the following conditions: An open circuit or high resistance condition. VSS high signal circuit and VSS low signal circuit shorted together. Did you find and correct a condition? If yes, go to step 14 . If no, go to step 11 .
7. Measure the resistance between terminal C2-21 and ground. Is the resistance greater than 50 k/ohms? If yes, go to step 10 . If no, go to next step.
8. Leave the J 39200 Digital Multimeter (DMM) connected between terminal C2-21 and ground. Disconnect the VSS. Measure the resistance between terminal C2-21 and ground. Is the resistance greater than 50 k/ohms? If yes, go to step 11 . If no, go to next step.
9. Repair the short to ground in the VSS high signal circuit. After repairs, go to step 14 .
10. Reconnect the J 39200 DMM between terminal C2-20 and C2-21. Measure the AC voltage with the J 39200 DMM while rotating the drive wheels by hand. Is the AC voltage equal to or greater than 0.5 V? If yes, go to step 13 . If no, go to next step.
11. Remove the VSS. Inspect the VSS and the VSS rotor for the following conditions: VSS damage. VSS rotor damage. Excessive air gap between the VSS rotor and the VSS. Incorrect alignment between the VSS and the VSS rotor. Repair or replace any of the above items as necessary. Did you find and correct a condition? If yes, go to step 14 . If no, go to next step.
12. Replace the VSS. After repairs, go to step 14 .
13. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
14. Using the scan tool, clear the DTCs. Start the engine. Idle at normal operating temperature. Operate the vehicle within the Conditions for Running DTC. Does the scan tool indicate that this diagnostic has run and passed? If yes, system is okay. If no, go to step 2 .

Ensure the VSS is correctly torqued to the transmission housing.

1. The battery voltage is between 10-18 volts.
2. The Intake Air Temperature (IAT) is less than 73°F (23°C) with the engine running; or the coolant temperature is less than 121°F (49°C) with the ignition ON, engine OFF for more than 3 seconds.

The heater line voltage is more than 8.1 volts with the relay OFF; or the heater line voltage is between 3.8-8.1 volts with the ignition OFF and the heater line voltage is less than 0.5 volt below battery voltage with the ignition ON; or the heater line voltage is less than 3.8 volts with the relay OFF and the reference line voltage is low with the relay OFF.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Is DTC P0380 also set? If yes, see «DTC P0380: GLOW PLUG CIRCUIT PERFORMANCE (CA)»(ref-138411-S14993678222002041700000) or «DTC P0380: GLOW PLUG CIRCUIT PERFORMANCE (FED)»(ref-138411-S08898743252002041700000) . If no, go to next step.
3. Turn OFF the ignition. Turn ON the ignition, with the engine OFF. Observe the IAH parameter with the scan tool. Does the scan tool display a voltage near 11-13 V with the IAH command ON and near 0 V with the IAH command OFF? If yes, go to step 9 . If no, go to next step.
4. Turn OFF the ignition. Touch the supply stud of the IAH with a test lamp connected to a good ground. Turn ON the ignition, with the engine OFF. Does the test lamp illuminate, and then turn OFF? If yes, go to step 9 . If no, go to next step.
5. Turn OFF the ignition. Disconnect the IAH relay connector. Turn ON the ignition, with the engine OFF. Probe the IAH relay harness connector ignition 1 voltage circuit with a test lamp connected to a good ground. Does the test lamp illuminate? If yes, go to next step. If no, go to step 10 .
6. Turn OFF the ignition. Verify that the IAH relay harness is disconnected. Probe the IAH control circuit on the ECM side of the harness with a test lamp connected to battery voltage. Turn ON the ignition, with the engine OFF. Does the test lamp illuminate, then turn OFF? If yes, go to step 11 . If no, go to next step.
7. Verify that the IAH relay harness is disconnected. Turn ON the ignition, with the engine OFF. Probe the IAH control circuit with a Digital Multimeter (DMM) connected to ground. Does the voltage measure less than 1 V? If yes, go to next step. If no, go to step 13 .
8. Test the IAH control circuit for an open or short to ground. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 14 .
9. Test for an open or short to ground on one of IAH supply voltage circuits between the IAH supply stud and the ECM. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 14 .
10. Repair the open or short to ground in the IAH ignition 1 voltage circuit. After repairs, go to step 17 .
11. Test for poor connections at the IAH relay. Did you find and correct the condition? If yes, go to step 17 . If no, go to next step.
12. Replace the intake air heater relay. After repairs, go to step 17 .
13. Repair the short to voltage on the relay control circuit. After repairs, go to step 17 .
14. Test for poor connections at the ECM. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 16 .
15. Replace the intake air heater. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 17 .
16. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
17. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
18. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. The battery voltage is between 10-18 volts.
2. The Intake Air Temperature (IAT) is less than 73°F (23°C) with the engine running; or the coolant temperature is less than 121°F (49°C) with the ignition ON, and with the engine OFF for more than 3 seconds.

1. The IAH line voltage is between 3.8-8.1 volts with the IAH relay OFF.
2. The IAH line voltage is less than 0.5 volt below battery voltage with the IAH relay ON.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Is DTC P0380 also set? If yes, see «DTC P0380: GLOW PLUG CIRCUIT PERFORMANCE (CA)»(ref-138411-S14993678222002041700000) or «DTC P0380: GLOW PLUG CIRCUIT PERFORMANCE (FED)»(ref-138411-S08898743252002041700000) . If no, go to next step.
3. Turn ON the ignition, with the engine OFF. Command the IAH ON and OFF with the scan tool. Observe the IAH parameter of the scan tool. Does the scan tool display a voltage within 11-13 V with the IAH command ON and near 0 V with the IAH command OFF? If yes, go to next step. If no, see «DTC P0540: INTAKE AIR HEATER CIRCUIT»(ref-138411-S18961946492002050100000) .
4. Turn OFF the ignition. Remove the nut and washer from the IAH. Touch the electrical terminal of the IAH with a test lamp connected to battery voltage. Does the test lamp illuminate? If yes, go to next step. If no, go to step 6 .
5. Repair the open in the IAH supply voltage circuit between the IAH Relay and the IAH. After repairs, go to step 7 .
6. Replace the intake air heater. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
7. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
8. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Is DTC P0602 set? If yes, go to next step. If no, go to step 5 .
3. Program the ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. Does DTC P0602 reset? If yes, go to next step. If no, go to step 6 .
4. Ensure that all tool connections are secure. Ensure that the programming equipment is operating correctly. Ensure that the correct software/calibration package is used. Attempt to program the ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. Does DTC P0602 reset? If yes, go to next step. If no, go to step 6 .
5. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
6. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Did the DTC fail this ignition cycle? If yes, go to step 2 . If no, go to next step.
7. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. The ignition is ON.
2. DTC U1800 or U2104 are not set.

The FICM detects an internal circuit fault.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Replace the fuel injection control module. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
3. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 1 .
4. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

The ignition is ON.

The feedback voltage does not match the output state.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Attempt to start the engine. Does the engine start? If yes, see «DIAGNOSTIC AIDS»(ref-138411-S38457211352002050200000) . If no, go to next step.
3. Turn OFF the ignition. Remove the ignition 1 relay using J 43244 Relay Puller Pliers. Disconnect the ECM connector containing the ignition 1 relay control circuit. Turn ON the ignition. Probe the ignition 1 relay control circuit with a test lamp connected to a good ground. Does the test lamp illuminate? If yes, go to step 5 . If no, go to next step.
4. Using a Digital Multimeter (DMM), measure the resistance of the coil circuit of the ignition 1 relay. Does the resistance measure 60-80 ohms? If yes, go to step 7 . If no, go to step 6 .
5. Repair the short to battery or ignition voltage on the ignition 1 relay control circuit. After repairs, go to step 8 .
6. Replace the ignition 1 relay. After repairs, go to step 8 .
7. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
8. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
9. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

If the engine starts, the ignition relay control circuit is shorted to power intermittently.

1. The engine speed is more than 400 RPM.
2. The ignition voltage is between 6-18 volts.

1. The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match.
2. The conditions are present for a minimum of 5 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Verify whether the Instrument Panel (IP) is operational. If the IP is completely inoperative, see appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Verify whether the MIL turns ON and OFF when commanded. Turn ON the ignition, with the engine OFF. Command the MIL ON and OFF using the scan tool. Repeat the commands as necessary. Does the MIL turn ON and OFF when commanded? If yes, go to next step. If no, go to step 4 .
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If yes, see «DIAGNOSTIC AIDS»(ref-138411-S08893239872002041200000) .
4. Inspect the fuse that supplies battery positive voltage to the MIL. Is the fuse open? If yes, go to step 10 . If no, go to next step.
5. Turn OFF the ignition. Disconnect the ECM. Turn ON the ignition. Is the MIL OFF? If yes, go to next step. If no, go to step 11 .
6. Turn OFF the ignition. Remove the fuse that supplies voltage to the MIL. Turn ON the ignition, with the engine OFF. Connect a Digital Multimeter (DMM) from the MIL control circuit to a good ground. Does the voltage measure 0 V? If yes, go to next step. If no, go to step 12 .
7. Turn OFF the ignition. Reinstall the fuse that supplies voltage to the MIL. Turn ON the ignition, with the engine OFF. Probe the MIL control circuit in the ECM harness connector with a fused jumper wire connected to ground. Does the MIL illuminate? If yes, go to step 15 . If no, go to next step.
8. Turn OFF the ignition. Remove the Instrument Panel Cluster (IPC). See appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Probe the MIL battery positive voltage circuit at the IP harness connector with a test lamp connected to a good ground. Does the test lamp illuminate? If yes, go to next step. If no, go to step 13 .
9. Test the MIL control circuit for an open or high resistance and repair as necessary. Did you find and correct a condition? If yes, go to step 18 . If no, go to step 14 .
10. Repair the short to ground in the battery positive voltage circuit. After repairs, go to step 18 .
11. Repair the short to ground in the MIL control circuit. After repairs, go to step 18 .
12. Repair the short to voltage on the MIL control circuit. After repairs, go to step 18 .
13. Repair the open in the MIL battery positive voltage circuit. After repairs, go to step 18 .
14. Inspect for poor connections at the IP and repair as necessary. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 16 .
15. Inspect for poor connections at the ECM and repair as necessary. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 17 .
16. Replace the IP. See appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. After repairs, go to step 18 .
17. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
18. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
19. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. If the ignition feed circuit is suspected of being open, inspect for other lamps on that circuit not illuminating. An open fuse causes the entire cluster to be inoperative. Also, if the fuse is open, transmission DTCs set.
2. Using Freeze Frame/Failure Records data may aid in locating an intermittent condition. If the DTC cannot be duplicated, the information included in the Freeze Frame/Failure Records data can be useful in determining how many miles since the DTC set. The Fail Counter and Pass Counter can also be used to determine how many ignition cycles the diagnostic reported a pass or a fail. Operate vehicle within the same Freeze Frame conditions, such as RPM, load, vehicle speed, temperature, etc., that were noted. This will isolate when the DTC failed.

The engine is running.

The TCM is requesting MIL illumination, or that the MIL request circuit is shorted to ground.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Connect a scan tool. Are there any transmission DTCs set? If yes, go to next step. If no, go to step 5 .
3. Diagnose and repair any transmission DTCs. See appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS. After repairs, go to next step.
4. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running in the DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
5. Disconnect the TCM. Connect a Digital Multimeter (DMM) from the MIL request circuit in the TCM harness connector to a good ground. Turn ON the ignition, with the engine OFF. Does the voltage measure near battery voltage? If yes, go to step 7 . If no, go to next step.
6. Test the MIL request circuit for a short to ground. Did you find and correct the condition? If yes, go to step 9 . If no, go to step 8 .
7. Replace the TCM. After repairs, go to step 9 .
8. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
9. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
10. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

The components are powered and ignition voltage is greater than 9 V and less than 18 V.

DTC P0703 sets when the vehicle accelerates 10 times with the brake switch in the ON position, or decelerates 10 times with the brake switch in the OFF position.

1. Use default assumption that brake is off.
2. TCM inhibits TCC engagement.

A scan tool can clear the code from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. This code indicates that the TCM did not see the proper input signal for service brake status during an acceleration or deceleration cycle. This may indicate an open or short in the TCC Brake Switch/Cruise Control Release Circuit or a faulty Stop Lamp Switch. Is the problem cause known? If yes, repair as necessary. After repairs, go to step 10. If no, go to next step.
3. Install the scan tool. Turn the ignition to the RUN position with the engine OFF. Record the DTC Failure Record Data. Apply and release the service brake. Does the scan tool indicate that the brake switch is toggling off and on? If yes, see «DIAGNOSTIC AIDS»(ref-138411-S33693719772002041200000). If no, go to next step.
4. With J 39200 Digital Multimeter (DMM), probe pins No. 5 and 7 on the TCM C1 connector. (Scheme 37) Apply and release the service brake. There should be no voltage reading at pin No. 7 when the brake is applied, with the brake released there should be 12V. Was voltage reading proper? If yes, go to step 9. If no, go to next step.
5. Go to the Stop Lamp Switch. With J 39200 DMM, probe pin "C" at the switch. (Scheme 37) Supply a ground connection at the other lead. Apply and release the service brake. Is the switch turning voltage ON and OFF? If yes, go to step 7. If no, go to next step.
6. With J 39200 DMM, measure voltage at pin "D" on the input side of the Stop Lamp Switch. Is voltage available? If yes, go to step 8. If no, repair power feed to Stop Lamp Switch.
7. Replace the TCC Brake Switch/Cruise Control wiring harness. After repairs, go to step 10.
8. Repair or replace the Stop Lamp Switch. After repairs, go to step 10.
9. Replace the TCM. After repairs, go to next step.
10. In order to verify your repair, clear the DTC and operate the vehicle under normal driving conditions. Did the DTC return? If yes, go to step 1. If no, system is okay.

Scheme 37

1. Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions: A bent terminal. A backed-out terminal. A damaged terminal. Poor terminal tension. A chafed wire. A broken wire inside the insulation.
2. When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.
3. You may have to drive the vehicle in order to experience a fault.

No Vehicle Speed Sensor (VSS) DTC P0500.

The ECM detects 7 changes in vehicle speed between 0 and 24 MPH without the ECM detecting a clutch pedal transition.

1. ECM does not illuminate the MIL.
2. The ECM disables cruise control.
3. The ECM disables power take-off.
4. The ECM records the operating conditions when the Conditions for Setting DTC are met. The ECM records this information as Freeze Frame and Failure Records.
5. The ECM stores DTC P0704 in ECM history.

1. The ECM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
2. The ECM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the ECM.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are present by this diagnostic or any other emission-related diagnostic.
4. A scan tool can clear the MIL/DTC.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Install a scan tool. Turn ON the ignition, with the engine OFF. Use the scan tool to monitor the clutch pedal position switch parameter. Apply and release the clutch pedal several times. Does the scan tool indicate a change in state when the clutch pedal is either applied or released? If yes, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM. If no, go to next step.
3. Inspect the adjustment of the clutch pedal position switch. Did you find and correct a condition? If yes, go to step 14 . If no, go to next step.
4. Turn OFF the ignition. Disconnect the clutch pedal position switch connector. Measure the voltage between pin "E" of the clutch pedal position switch electrical connector and a good ground. Does the J 39200 Digital Multimeter (DMM) indicate battery voltage? If yes, go to next step. If no, go to step 11 .
5. Use a fused jumper wire to connect pin "E" and pin "F" of the clutch pedal position switch electrical connector. Turn ON the ignition, with the engine OFF. Use the scan tool to monitor the clutch pedal position switch parameter. Does the scan tool display that the clutch is released? If yes, go to step 8 . If no, go to next step.
6. Turn OFF the ignition. Disconnect the ECM connector C1. Use the J 39200 Digital Multimeter (DMM) in order to test for continuity on the clutch pedal switch signal circuit (CKT 48) between pin "F" of the clutch pedal position switch and pin No. 35 of ECM connector C1. Did you detect continuity? If yes, go to next step. If no, go to step 10 .
7. Use the J 39200 DMM in order to test for continuity between pin "F" of the clutch pedal position switch and a good ground. Did you detect continuity? If yes, go to step 10 . If no, go to step 9 .
8. Inspect for a loose connection at the clutch pedal position switch connector. Repair the condition as necessary. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 12 .
9. Inspect for a loose connection at the ECM. Repair the condition as necessary. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 13 .
10. Repair the open or short to ground in the clutch position switch signal circuit (CKT 48). After repairs, go to step 14 .
11. Repair the open in the clutch position switch feed circuit (CKT 441). After repairs, go to step 14 .
12. Replace the clutch pedal position switch. After repairs, go to step 14 .
13. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
14. Select the DTC. Select Clear Info. Operate the vehicle within the Conditions for Running DTC. Select Specific DTC. Enter DTC P0704. Has the test run and passed? If yes, system is okay. If no, go to step 1 .

1. The components are powered and ignition voltage is greater than 9 V and less than 18 V.
2. Engine speed is greater than 200 RPM and less than 7500 RPM for 5 seconds.

DTC P0708 sets when the TCM detects an invalid condition and parity errors occurring over consecutive ignition cycles.

1. While diagnostic response is active one of the following conditions can occur: If the shift selector is moved to NEUTRAL then the transmission will shift to NEUTRAL. If the selector is moved to REVERSE, then the transmission will shift to REVERSE. If the shift selector is moved to forward, then the transmission will shift to 3rd or 5th range, unless the transmission is compromised by overspeeding or direction change, then the transmission will shift to NEUTRAL.
2. DTC P0708 will be stored in the TCM history.
3. The TCM freezes shift adapts.
4. Due to this failure and associated response, DTC P0722 and DTC P0845 also set.
5. TCM inhibits TCC engagement.

A scan tool can clear the code from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Check the Park/Neutral Position Switch and shift linkage for proper adjustment. If the Park/Neutral Position switch and shift linkage are properly adjusted, go to next step.
3. Install the scan tool. Turn the ignition ON with the engine OFF. Record the DTC Failure Records. Using the scan tool, monitor PRNDL A, B, C, P status while moving the shift selector through each selector position. See «PARK/NEUTRAL POSITION SWITCH LOGIC»(ref-138411-S12266862892002041200000) table. Does each switch toggle ON and OFF in the correct sequence and does the range displayed on the scan tool match the actual range for the selector position chosen? If yes, see «DIAGNOSTIC AIDS»(ref-138411-S35332710682002041200000). If no, go to next step.
4. Turn the ignition OFF. Disconnect the C2 connector at the TCM. Install J 39700 Breakout Box and J 43799 Breakout Box Adapter. Turn the ignition ON. In sequence, connect connector C2 pin 20 to connector C2 pins 5, 6, 7, and 8. (Scheme 38) Using the scan tool, monitor PRNDL A, B, C, P status. See «CONNECTOR PIN IDENTIFICATION»(ref-138411-S39215321482002041200000) table. Does each switch toggle ON and OFF in the correct sequence as each pin is grounded? If yes, go to next step. If no, go to step 8. CONNECTOR PIN IDENTIFICATION Circuit Pin Number A 5 B 6 C 7 P 8 On - Open Circuit Off - Grounded Circuit
5. Turn the ignition OFF. Reconnect the C2 connector to the TCM. Disconnect the 4-pin connector at the Park/Neutral Position switch. Turn the ignition ON. Using the scan tool, monitor PRNDL A, B, C, P status. In sequence, connect pins 4A, 4B, 4C, and 4D in the 4-way PNP connector to pin 7D (use pin H on the J 44722 magnetic overlay for this operation) in the 7-way PNP connector (use J 39700 breakout box and J 44722 transmission harness to do this step). Does the scan tool indicate the status as ON? If yes, go to next step. If no, go to step 7.
6. Replace the Park/Neutral Position Switch. After repairs, go to step 9.
7. Inspect and repair the transmission wiring harness assembly. After repairs, go to step 9.
8. Replace the TCM. After repairs, go to next step.
9. To verify your repair, clear the DTC. Using the scan tool monitor PRNDL A, B, C, P status while moving the shift selector through each selector position. See «PARK/NEUTRAL POSITION SWITCH LOGIC»(ref-138411-S12266862892002041200000) table. Does each switch toggle ON and OFF in the correct sequence as the selector is moved? If yes, system is okay. If no, go to step 1.

PARK/NEUTRAL POSITION SWITCH LOGIC

Scheme 38

1. Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions: A bent terminal. A backed-out terminal. A damaged terminal. Poor terminal tension. A chafed wire. A broken wire inside the insulation.
2. When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.
3. You may have to drive the vehicle in order to experience a fault.

1. DTCs P0192, P0193 or P1635 are not set.
2. The ignition is ON.

The difference between commanded fuel pressure and actual fuel pressure is more than 20 MPa; or the FRP Regulator Fuel Flow is more than 15,000 mm 3 at 800 RPM, or more than 38,000 mm 3 at 2000 RPM.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.
4. The driver information center, if equipped, may display a message.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Use a scan tool in order to clear the MIL and the DTC.

Conditions For Clearing DTC (Federal)

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
3. Use a scan tool in order to clear the DTC.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Is DTC P0168 also set? If yes, see «DTC P0168: FUEL TEMPERATURE SENSOR HIGH»(ref-138411-S42374759562002041600000) . If no, go to next step.
3. Attempt to start the engine. Does the engine start and idle? If yes, go to next step. If no, see ENGINE CRANKS BUT DOES NOT RUN in appropriate BASIC DIAGNOSTIC PROCEDURES article.
4. Turn ON the ignition, with the engine OFF. Observe the Actual Fuel Rail Pressure parameter with a scan tool. Is the Actual Fuel Rail Pressure Parameter 1.2-1.4 MPa? If yes, go to next step. If no, go to step 9 .
5. Install the J 44638 Vacuum gauge on the fuel fitting located on the right side front of the engine. Start and run the engine at idle. Observe the vacuum gauge while increasing RPM slowly to Wide Open Throttle (WOT) in park or neutral. Does the vacuum measure less than 5 in. Hg through the entire RPM range? If yes, go to next step. If no, go to step 10 .
6. Start and idle the engine until the idle speed drops to 680 RPM. Command the fuel pressure control to 160 MPa with a scan tool. Observe the Actual Fuel Rail Pressure parameter with a scan tool. Is the Actual Fuel Rail Pressure parameter more than 145 MPa? If yes, go to next step. If no, diagnose fuel system high pressure side. See «FUEL SYSTEM DIAGNOSIS - HIGH PRESSURE SIDE»(ref-150429-S06204432152002111300000) under FUEL SYSTEMS (DIESEL) in SYSTEM & COMPONENT TESTING - TRUCKS -EXCEPT TRACKER article.
7. Ensure that the J 44638 Vacuum gauge is still installed on the engine. Operate the vehicle within the conditions for which the customer complaint occurs. Does the vacuum measure less than 12 in. Hg through the entire operating range? If yes, go to next step. If no, go to step 10 .
8. Ask the customer if there has been a power-enhancing device attached to the fuel rail pressure sensor circuits. What was the customers answer? If yes, go to step 16 . If no, diagnose fuel system high pressure side. See «FUEL SYSTEM DIAGNOSIS - HIGH PRESSURE SIDE»(ref-150429-S06204432152002111300000) under FUEL SYSTEMS (DIESEL) in SYSTEM & COMPONENT TESTING - TRUCKS -EXCEPT TRACKER article.
9. Disconnect the fuel rail pressure sensor. Observe the Actual Fuel Rail Pressure with a scan tool. Does the Actual Fuel Rail Pressure measure more than 175 MPa? If yes, go to step 14 . If no, go to step 13 .
10. Replace the fuel filter. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
11. Ensure that the J 44638 Vacuum gauge is still installed on the engine. Start and run the engine under the conditions for which the high vacuum occurred in the previous test. Observe the J 44638. Does the vacuum measure less than or equal to 5 in. Hg at idle or 12 in. Hg at high speed? If yes, go to step 16 . If no, go to next step.
12. Repair the restriction in the fuel supply lines between the fuel tank and the fuel injection pump. After repairs, go to step 16 .
13. Check the fuel rail pressure sensor signal circuit for a short to ground. Repair as necessary. Did you find and correct the condition? If yes, go to step 16 . If no, go to step 15 .
14. Replace the fuel rail pressure sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 16 .
15. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
16. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
17. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

This DTC does not set for an idle condition.

A number of conditions may cause DTC P0087 and DTC P1093 to set

1. Excessive fuel return to the tank.
2. A fuel injection pump failure.
3. A fuel pressure regulator failure.

If you have to prime the fuel system, check for the following conditions

1. A restricted fuel supply line.
2. A fuel supply line air leak.

A sticking Fuel Pressure Regulator may set this DTC.

If the problem is still intermittent, see INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM.

1. DTCs P0192, P0193, or P1635 are not set.
2. The ignition is ON.

The commanded fuel injection pump flow is more than 12,000 mm 3 .

1. The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Is DTC P1093 also set? If yes, see «DTC P1093: FUEL RAIL PRESSURE OUT OF RANGE»(ref-138411-S27308629622002041500000) . If no, go to next step.
3. Attempt to start the engine. Does the engine start and continue to run? If yes, go to next step. If no, see «NO-START - ENGINE CRANKS OKAY (6.6L DIESEL)»(ref-149936-S07095423632002111300000) under NO-START DIAGNOSIS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
4. Is the customer concern also a surging idle? If yes, diagnose fuel system high pressure side. See «FUEL SYSTEM DIAGNOSIS - HIGH PRESSURE SIDE»(ref-150429-S06204432152002111300000) under FUEL SYSTEMS (DIESEL) in SYSTEM & COMPONENT TESTING - TRUCKS -EXCEPT TRACKER article. If no, go to next step.
5. Start and idle the engine. Observe the FRP regulator fuel flow with a scan tool. Does the FRP regulator fuel flow measure more than 12,000 mm 3 ? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-138411-S14592784002002050200000) .
6. Test the fuel pressure regulator solenoid control circuit between the ECM and the fuel pressure regulator for a short to ground. Did you find and correct the condition? If yes, go to step 9 . If no, go to next step.
7. Test for an intermittent or poor connection at the ECM. Did you find and correct the condition? If yes, go to step 9 . If no, go to next step.
8. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
9. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
10. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. If you have to prime the fuel system, check for the following conditions: A restricted fuel supply line. A fuel supply line air leak.
2. If the problem is still intermittent, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.

1. The ignition switch is in the crank or run position.
2. The ignition voltage is between 7-16 volts.

1. The ECM detects a condition with more than one APP sensor.
2. All of the above conditions present for less than 1 second.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. If one or more APP sensor DTCs are set for a single APP sensor, the following occurs: The control module will not command Reduced Engine Power mode. The control module will use the remaining two APP sensors to calculate throttle response.
5. If certain multiple APP sensor DTCs are set for more than one APP sensor, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to a predetermined value to limit the amount of throttle control. The message center displays Reduced Engine Power.
6. If all three APP sensors are out of range, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to 0 percent. The control module only allows the engine to idle. The message center displays Reduced Engine Power.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Is DTC P1635 set? If yes, see «DTC P1635: 5-VOLT REFERENCE 1 CIRCUIT»(ref-138411-S09965080052002041200000) . If no, go to next step.
3. This DTC indicates that 2 or more APP sensor DTCs are set. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) .

1. APP sensor 1 and APP sensor 3, 5-volt reference circuits are internally connected within the ECM.
2. The APP sensor 2, 5-volt reference circuit is shared with the Barometric (BARO) pressure sensor and the turbo boost solenoid and they are internally connected within the ECM.
3. If the problem is intermittent, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.

1. DTCs P0461, P0462, P0463, P0500, P1431, P1432, P1433 are not set.
2. The engine is running.
3. The vehicle speed is 0 MPH.
4. The primary fuel level is less than 6.6 gal (25 L).
5. The secondary fuel level is between .7-2.6 gal (3-10 L).
6. The above conditions are met for 20 seconds before the secondary pump is commanded ON.
7. The secondary fuel pump is commanded ON for 120 seconds.

The ECM does not detect a change of 4 L (1.06 gal) in both the primary and secondary fuel level sensors with the secondary pump commanded ON for 120 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Turn ON the ignition, with the engine OFF. Command the fuel pump ON and OFF with a scan tool. Does the fuel pump relay click as you command the fuel pump ON and OFF? If yes, go to step 8 . If no, go to next step.
3. Remove the fuel pump relay from the underhood electrical center. Probe the ground circuit of the fuel pump relay with a test lamp connected to battery voltage. Is the test lamp illuminated? If yes, go to next step. If no, go to step 20 .
4. Probe the control circuit of the fuel pump relay with a test lamp connected to a good ground. Command the fuel pump ON and OFF with a scan tool. Does the test lamp turn ON and OFF? If yes, go to step 17 . If no, go to next step.
5. Does the test lamp remain illuminated with each command? If yes, go to next step. If no, go to step 7 .
6. Test the control circuit of the fuel pump relay for a short to battery voltage. Did you find and correct the condition? If yes, go to step 26 . If no, go to step 25 .
7. Test the control circuit of the fuel pump relay for an open or a short to ground. Did you find and correct the condition? If yes, go to step 26 . If no, go to step 19 .
8. Command the fuel pump ON with a scan tool. Does the fuel pump run? If yes, go to step 13 . If no, go to next step.
9. Remove the fuel pump relay from the underhood electrical center. Turn ON the ignition, with the engine OFF. Probe the ignition 1 voltage circuit of the fuel pump relay with a test lamp connected to a good ground. Is the test lamp illuminated? If yes, go to next step. If no, go to step 22 .
10. Probe the fuel pump supply circuit with a test lamp connected to battery voltage. Does the test lamp blink? If yes, go to step 17 . If no, go to next step.
11. Test the fuel pump supply circuit for an open. Did you find and correct the condition? If yes, go to step 26 . If no, go to next step.
12. Probe the ground circuit of the fuel pump with a test lamp connected to battery voltage. Is the test lamp illuminated? If yes, go to step 18 . If no, go to step 21 .
13. Monitor the rear fuel level sensor voltage with a scan tool. Is the rear fuel level sensor voltage above 1 V? If yes, go to step 15 . If no, go to next step.
14. Add 5 Gal (19 L) of fuel to the fuel tank. Go to next step.
15. Turn OFF the ignition. Remove the fuel pump relay from the underhood electrical center. Jumper the ignition 1 voltage circuit to the fuel pump supply voltage circuit, at the underhood electrical center. Turn ON the ignition, with the engine OFF. Monitor the rear fuel level sensor voltage with a scan tool. Does the rear fuel level sensor voltage decrease as the fuel pump is operating? If yes, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM. If no, go to next step.
16. Inspect for the following conditions: A restriction in the fuel lines between the front and rear fuel tanks. The rear fuel sender for a restriction. Did you find and correct the condition? If yes, go to step 26 . If no, go to step 24 .
17. Inspect for poor connections at the harness connector of the fuel pump relay. Did you find and correct the condition? If yes, go to step 26 . If no, go to step 23 .
18. Inspect for poor connections at the harness connector of the fuel pump. Did you find and correct the condition? If yes, go to step 26 . If no, go to step 24 .
19. Inspect for poor connections at the harness connector of the ECM. Did you find and correct the condition? If yes, go to step 26 . If no, go to step 25 .
20. Repair the open ground circuit of the fuel pump relay. After repairs, go to step 26 .
21. Repair the open ground circuit of the fuel pump. After repairs, go to step 26 .
22. Repair the open ignition 1 voltage circuit of the fuel pump relay. After repairs, go to step 26 .
23. Replace the fuel pump relay. After repairs, go to step 26 .
24. Replace the fuel pump. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 26 .
25. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
26. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
27. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0405, P0406, P0489, P0490, P0500, P1639, P2141, P2142, P2144, or P2145 are not set.
2. The engine is running.
3. The Barometric (BARO) pressure sensor pressure is more than 72 kPa.
4. The battery charge is between 9-16 volts.
5. The vehicle speed is less than 1 MPH.
6. The engine speed is between 600-700 RPM.
7. The coolant temperature is between 32-176°F (0-80°C).

1. The ECM detects an intake leak more than the calibrated value, internal to ECM.
2. The condition is met for 2 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Does the scan tool display any other DTCs set? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-138411-S32874856902002050200000) .
4. Turn OFF the ignition. Repair the air leak in one or more of the following components: The air induction system after the MAF sensor. The intake gaskets. The EGR tower gasket. After repairs, go to next step.
5. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
6. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. The most likely cause of the DTC is a leaking intake duct after the MAF sensor.
2. To run the diagnostic test the following conditions must be met: The engine is at full operating temperature. The vehicle is in drive. The vehicle has been idling for more than 1 minute.
3. After meeting these conditions, shift the vehicle into park, and hold the engine speed steady between 1500-2100 RPM for 30 seconds. If the diagnostic test still fails to run, the vehicle must be driven.

1. The engine is running.
2. The ignition voltage is between 6-18 volts.

1. The ECM detects that the command state and the actual state of the control circuit do not match.
2. The condition exists for less than one second.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Start and idle the engine. Monitor the DTC Failed This Ignition parameter with a scan tool. Do any of the DTCs P1223-1244 fail this ignition cycle? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
4. Is there only 1 fuel injector control circuit DTC set? If yes, go to step 6 . If no, go to next step.
5. Are all 8 of the fuel injector control circuit DTCs set? If yes, go to step 9 . If no, go to step 8 .
6. Turn OFF the ignition. Disconnect the harness connector C1 of the ECM. Install a jumper wire between the FICM relay control circuit in the connector and ground. Turn ON the ignition, with the engine OFF. Measure the voltage of the appropriate fuel injector control circuit with a DMM. See «DIAGNOSTIC AIDS»(ref-138411-S11012152322002050200000) . Is the voltage near the specified value? If yes, go to step 13 . If no, go to next step.
7. Turn OFF the ignition. Disconnect the harness connectors of the FICM. Test the appropriate fuel injector control circuit for an open. Did you find and correct the condition? If yes, go to step 16 . If no, go to step 12 .
8. Turn OFF the ignition. Disconnect the harness connector C1 of the ECM. Probe the affected fuel injector control circuits with a test lamp connected to battery voltage. Does the test lamp illuminate on any of the fuel injector control circuits? If yes, go to step 10 . If no, go to step 15 .
9. Turn OFF the ignition. Disconnect the harness connector C1 of the ECM. Turn ON the ignition, with the engine OFF. Measure the voltage from all of the fuel injector control circuits with a DMM. Is the voltage more than 0 V on any of the fuel injector control circuits? If yes, go to step 11 . If no, go to step 15 .
10. Test the appropriate fuel injector control circuit for a short to ground. Did you find and correct the condition? If yes, go to step 16 . If no, go to step 14 .
11. Test the appropriate fuel injector control circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 16 . If no, go to step 14 .
12. Inspect for poor connections at the harness connector of the FICM. Did you find and correct the condition? If yes, go to step 16 . If no, go to step 14 .
13. Inspect for poor connections at the harness connector of the ECM. Did you find and correct the condition? If yes, go to step 16 . If no, go to step 15 .
14. Replace the FICM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 16 .
15. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
16. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
17. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

To determine which fuel injector control circuit is malfunctioning, see CYLINDER IDENTIFICATION table.

CYLINDER IDENTIFICATION

1. The ignition is ON.
2. DTCs U1800 or U2104 are not set.

The ECM detects a circuit fault related to the high voltage circuit to cylinders 1, 4, 6, and 7.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Is DTC P0201, DTC P0204, DTC P0206 or DTC P0207 also set? If yes, see «DTC P0201-P0208: FUEL INJECTOR CONTROL CIRCUITS»(ref-138411-S06277281172002041200000) . If no, go to next step.
3. Replace the FICM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
4. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
5. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. The ignition is ON.
2. DTC U1800 or U2104 are not set.

The ECM detects a circuit fault related to the high voltage circuit to cylinders 2, 3, 5, and 8.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Is DTCs P0202, P0203, P0205, or P0208 also set? If yes, see «DTC P0201-P0208: FUEL INJECTOR CONTROL CIRCUITS»(ref-138411-S06277281172002041200000) . If no, go to next step.
3. Replace the FICM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
4. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
5. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. The ignition switch is in the crank or run position.
2. The ignition voltage is between 7-16 volts.

1. The ECM microprocessor can not process APP analog data into digital data.
2. All of the above conditions are present for less than 1 second.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
3. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
4. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. DTCs P1277, P1278, P1287, P1288, P1635, or P1639 are not set.
2. The ignition switch is in the crank or run position.
3. The ignition voltage is between 7-16 volts.

1. The APP sensor 1 and APP sensor 2 are more than 10 percent out of range of each other.
2. All of the above conditions present for less than 1 second.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. If one or more APP sensor DTCs are set for a single APP sensor, the following occurs: The control module will not command Reduced Engine Power mode. The control module will use the remaining two APP sensors to calculate throttle response.
5. If certain multiple APP sensor DTCs are set for more than one APP sensor, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to a predetermined value to limit the amount of throttle control. The message center displays Reduced Engine Power.
6. If all three APP sensors are out of range, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to 0 percent. The control module only allows the engine to idle. The message center displays Reduced Engine Power.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to step 4 . If no, go to next step.
3. Select the Diagnostic Trouble Code (DTC) option using the scan tool. Lightly touch and move the related APP wiring harnesses and connectors while monitoring the DTC Information. Did this DTC fail this ignition cycle, during the above test? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
4. Is DTC P1272 also set? If yes, go to step 6 . If no, go to next step.
5. Is DTC P1273 also set? If yes, go to step 9 .
6. Turn OFF the ignition. Disconnect the APP sensor harness connector. Turn ON the ignition. With a test lamp connected to ground, test for voltage at the APP sensor 2, 5-volt reference circuit. Does the test lamp illuminate? If yes, go to next step. If no, go to step 13 .
7. With a test lamp connected to ground, test for voltage at the APP sensor 2 signal circuit. Does the test lamp illuminate? If yes, go to next step. If no, go to step 14 .
8. Connect a test lamp between the APP sensor 2, 5-volt reference circuit and the APP sensor 2 low reference circuit. Does the test lamp illuminate? If yes, go to step 18 . If no, go to step 15 .
9. Turn OFF the ignition. Disconnect the APP sensor harness connector. Turn ON the ignition. With a test lamp connected to ground, test for voltage at the APP sensor 1, 5-volt reference circuit. Does the test lamp illuminate? If yes, go to next step. If no, go to step 16 .
10. Connect the test lamp between the APP sensor 1, 5-volt reference circuit and the APP sensor 1 low reference circuit. Does the test lamp illuminate? If yes, go to next step. If no, go to step 17 .
11. Connect a fused jumper wire between the APP sensor 1 signal circuit and the APP sensor 1, 5-volt reference circuit. With a scan tool, observe the APP sensor 1 voltage parameter. Does the scan tool indicate voltage at 5 V? If yes, go to step 18 . If no, go to next step.
12. Turn OFF the ignition. Disconnect the ECM harness connector that contains the APP sensor 1 signal circuit. With a Digital Multimeter (DMM), test the APP sensor 1 signal circuit for high resistance. Did you find and correct the condition? If yes, go to step 22 . If no, go to step 20 .
13. Turn OFF the ignition. Disconnect the ECM harness connector that contains the APP sensor 2, 5-volt reference circuit. With a DMM, test the APP sensor 2, 5-volt reference circuit for high resistance. Did you find and correct the condition? If yes, go to step 22 . If no, go to step 20 .
14. Turn OFF the ignition. Disconnect the ECM harness connector that contains the APP sensor 2 signal circuit. Turn ON the ignition. With a DMM, test the APP sensor 2 signal circuit for high resistance. Did you find and correct the condition? If yes, go to step 22 . If no, go to step 20 .
15. Turn OFF the ignition. Disconnect the ECM harness connector that contains the APP sensor 2 low reference circuit. With a DMM, test the APP sensor 2 low reference circuit for resistance. Did you find and correct the condition? If yes, go to step 22 . If no, go to step 20 .
16. Turn OFF the ignition. Disconnect the ECM harness connector that contains the APP sensor 1, 5-volt reference circuit. Turn ON the ignition. With a DMM, test the APP sensor 1, 5-volt reference circuit for high resistance. Did you find and correct the condition? If yes, go to step 22 . If no, go to step 20 .
17. Turn OFF the ignition. Disconnect the ECM harness connector that contains the APP sensor 1 low reference circuit. With a DMM, test the APP sensor 1 low reference circuit for resistance. Did you find and correct the condition? If yes, go to step 22 . If no, go to step 20 .
18. Inspect for poor connections at the harness connector of the APP sensor. Did you find and correct the condition? If yes, go to step 22 . If no, go to next step.
19. Replace the APP sensor assembly. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 22 .
20. Inspect for poor connections at the harness connector of the ECM. Did you find and correct the condition? If yes, go to step 22 . If no, go to next step.
21. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
22. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
23. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. DTCs P1282, P1283, P1287, P1288, P1635, or P1639 are not set.
2. The ignition switch is in the crank or run position.
3. The ignition voltage is between 7-16 volts.

1. The APP sensor 2 and APP sensor 3 are more than 10 percent out of range of each other.
2. All of the above conditions present for less than 1 second.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. If one or more APP sensor DTCs are set for a single APP sensor, the following occurs: The control module will not command Reduced Engine Power mode. The control module will use the remaining two APP sensors to calculate throttle response.
5. If certain multiple APP sensor DTCs are set for more than one APP sensor, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to a predetermined value to limit the amount of throttle control. The message center displays Reduced Engine Power.
6. If all three APP sensors are out of range, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to 0 percent. The control module only allows the engine to idle. The message center displays Reduced Engine Power.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to step 4 . If no, go to next step.
3. Select the Diagnostic Trouble Code (DTC) option using the scan tool. Lightly touch and move the related APP wiring harnesses and connectors while monitoring the DTC Information. Did this DTC fail this ignition cycle, during the above test? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
4. Is DTC P1271 also set? If yes, see «DTC P1271: APP SENSOR 1-2 PERFORMANCE»(ref-138411-S37583068402002050200000) . If no, go to next step.
5. Turn OFF the ignition. Disconnect the APP sensor harness connector. Turn ON the ignition. With a test lamp connected to ground, test for voltage at the APP sensor 3, 5-volt reference circuit. Does the test lamp illuminate? If yes, go to next step. If no, go to step 8 .
6. With a test lamp connected to ground, test for voltage at the APP sensor 3 signal circuit. Does the test lamp illuminate? If yes, go to next step. IF no, go to step 9 .
7. Connect a test lamp between the APP sensor 3, 5-volt reference circuit and the APP sensor 3 low reference circuit. Does the test lamp illuminate? If yes, go to step 11 . If no, go to step 10 .
8. Turn OFF the ignition. Disconnect the ECM harness connector that contains the APP sensor 3, 5-volt reference circuit. With a Digital Multimeter (DMM), test the APP sensor 3, 5-volt reference circuit for high resistance. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 13 .
9. Turn OFF the ignition. Disconnect the ECM harness connector that contains the APP sensor 3 signal circuit. Turn ON the ignition. With a DMM, test the APP sensor 3 signal circuit for high resistance. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 13 .
10. Turn OFF the ignition. Disconnect the ECM harness connector that contains the APP sensor 3 low reference circuit. With a DMM, test the APP sensor 3 low reference circuit for high resistance. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 13 .
11. Inspect for poor connections at the harness connector of the APP sensor. Did you find and correct the condition? If yes, go to step 15 . If no, go to next step.
12. Replace the APP sensor assembly. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 15 .
13. Inspect for poor connections at the harness connector of the ECM. Did you find and correct the condition? If yes, go to step 15 . If no, go to next step.
14. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
15. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
16. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. DTCs P1277, P1278, P1287, P1288, P1635, or P1639 are not set.
2. The ignition switch is in the crank or run position.
3. The ignition voltage is between 7-16 volts.

1. APP sensor 1 and APP sensor 3 are more than 10 percent out of range of each other.
2. All of the above conditions present for less than 1 second.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. If one or more APP sensor DTCs are set for a single APP sensor, the following occurs: The control module will not command Reduced Engine Power mode. The control module will use the remaining two APP sensors to calculate throttle response.
5. If certain multiple APP sensor DTCs are set for more than one APP sensor, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to a predetermined value to limit the amount of throttle control. The message center displays Reduced Engine Power.
6. If all three APP sensors are out of range, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to 0 percent. The control module only allows the engine to idle. The message center displays Reduced Engine Power.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Is DTC P1271 also set? If yes, see «DTC P1271: APP SENSOR 1-2 PERFORMANCE»(ref-138411-S37583068402002050200000) . If no, go to next step.
3. If DTC P1272 is also set, see «DTC P1272: ACCELERATOR PEDAL POSITION SENSOR 2»(ref-138411-S40118794852002050200000) .

1. DTCs P1635 or P1639 are not set.
2. The ignition switch is in the crank or run position.
3. The ignition voltage is between 7-16 volts.

1. The APP sensor 1 voltage is less than 0.25 volts.
2. All of the above conditions present for less than 1 second.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. If one or more APP sensor DTCs are set for a single APP sensor, the following occurs: The control module will not command Reduced Engine Power mode. The control module will use the remaining two APP sensors to calculate throttle response.
5. If certain multiple APP sensor DTCs are set for more than one APP sensor, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to a predetermined value to limit the amount of throttle control. The message center displays Reduced Engine Power.
6. If all three APP sensors are out of range, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to 0 percent. The control module only allows the engine to idle. The message center displays Reduced Engine Power.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to step 4 . If no, go to next step.
3. Select the Diagnostic Trouble Code (DTC) option using the scan tool. Lightly touch and move the related APP wiring harnesses and connectors while monitoring the DTC Information. Did this DTC fail this ignition cycle, during the above test? If yes, go to step 10 . If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
4. Disconnect the APP sensor harness connector. With a Digital Multimeter (DMM), test for voltage at the APP sensor 1, 5-volt reference circuit. Does the DMM indicate voltage at 5.17 V? If yes, go to next step. If no, go to step 6 .
5. Connect a fused jumper between the APP sensor 1, 5-volt reference circuit and the APP sensor 1 signal circuit. With a scan tool observe the APP sensor 1 voltage parameter. Does the scan tool indicate APP sensor 1 voltage at 5 V? If yes, go to step 11 . If no, go to step 8 .
6. Disconnect the ECM harness connector containing the APP sensor 1, 5-volt reference circuit. Test the APP sensor 1, 5-volt reference circuit for a short to ground. Did you find and correct the condition? If yes, go to step 15 . If no, go to next step.
7. Test the APP sensor 1, 5-volt reference circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 12 .
8. Disconnect the ECM harness connector containing the APP sensor 1 signal circuit. Test the APP sensor 1 signal circuit for a short to ground. Did you find and correct the condition? If yes, go to step 15 . If no, go to next step.
9. Test the APP sensor 1 signal circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 12 .
10. Repair the intermittent condition as necessary. Did you complete the repair? After repairs, go to step 15 .
11. Inspect for poor connections at the harness connector of the APP sensor. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 13 .
12. Inspect for poor connections at the harness connector of the ECM. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 14 .
13. Replace the APP sensor assembly. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 15 .
14. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
15. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
16. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. DTCs P1635 or P1639 are not set.
2. The ignition switch is in the crank or run position.
3. The ignition voltage is between 7-16 volts.

1. The APP sensor 1 voltage is more than 4.75 volts.
2. All of the above conditions are present for less than 1 second.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. If one or more APP sensor DTCs are set for a single APP sensor, the following occurs: The control module will not command Reduced Engine Power mode. The control module will use the remaining two APP sensors to calculate throttle response.
5. If certain multiple APP sensor DTCs are set for more than one APP sensor, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to a predetermined value to limit the amount of throttle control. The message center displays Reduced Engine Power.
6. If all three APP sensors are out of range, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to 0 percent. The control module only allows the engine to idle. The message center displays Reduced Engine Power.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to step 4 . If no, go to next step.
3. Select the Diagnostic Trouble Code (DTC) option on the scan tool. Lightly touch and move the related APP sensor wiring harnesses and connectors while monitoring the DTC Information. Did this DTC fail this ignition cycle, during the above test? If yes, go to step 9 . If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
4. Disconnect the APP sensor harness connector. With a scan tool, observe the APP sensor 1 voltage parameter. Does the scan tool indicate the APP sensor 1 voltage at 0 V? If yes, go to next step. If no, go to step 6 .
5. Connect a fused jumper between the APP sensor 2 signal circuit and the APP sensor 1 low reference circuit. With a scan tool observe the APP sensor 2 voltage parameter. Does the scan tool indicate APP sensor 2 voltage at 0 V? If yes, go to step 10 . If no, go to step 8 .
6. Turn OFF the ignition. Disconnect the ECM harness connector containing the APP sensor 1 signal circuit. Turn ON the ignition. Test the APP sensor 1 signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 14 . If no, go to next step.
7. Turn OFF the ignition. Disconnect the other ECM harness connector. Test the APP sensor 1, signal circuit for a short to all other APP circuits at the APP sensor harness connector. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 11 .
8. Disconnect the ECM harness connector containing the APP sensor 1 low reference circuit. Test the APP sensor 1 low reference circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 11 .
9. Repair the intermittent condition as necessary. After repairs, go to step 14 .
10. Inspect for poor connections at the harness connector of the APP sensor. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 12 .
11. Inspect for poor connections at the harness connector of the ECM. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 13 .
12. Replace the APP sensor assembly. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 14 .
13. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
14. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
15. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. DTCs P1635 or P1639 are not set.
2. The ignition switch is in the crank or run position.
3. The ignition voltage is between 7-16 volts.

1. The APP sensor 2 voltage is less than 0.25 volt.
2. All of the above conditions present for less than 1 second.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. If one or more APP sensor DTCs are set for a single APP sensor, the following occurs: The control module will not command Reduced Engine Power mode. The control module will use the remaining two APP sensors to calculate throttle response.
5. If certain multiple APP sensor DTCs are set for more than one APP sensor, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to a predetermined value to limit the amount of throttle control. The message center displays Reduced Engine Power.
6. If all three APP sensors are out of range, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to 0 percent. The control module only allows the engine to idle. The message center displays Reduced Engine Power.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to step 4 . If no, go to next step.
3. Select the Diagnostic Trouble Code (DTC) option using the scan tool. Lightly touch and move the related APP wiring harnesses and connectors while monitoring the DTC Information. Did this DTC fail this ignition cycle, during the above test? If yes, go to step 8 . If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
4. Disconnect the APP sensor harness connector. With a Digital Multimeter (DMM), test for voltage at the APP sensor 2, 5-volt reference circuit. Does the DMM indicate voltage at 5.17 V? If yes, go to next step. If no, go to step 6 .
5. With a DMM, test for voltage at the APP sensor 2 signal circuit. Does the DMM indicate voltage at 5.05 V? If yes, go to step 9 . If no, go to step 7 .
6. Disconnect the ECM harness connector containing the APP sensor 2, 5-volt reference circuit. Test the APP sensor 2, 5-volt reference circuit for an open. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 10 .
7. Disconnect the ECM harness connector containing the APP sensor 2 signal circuit. Test the APP sensor 2 signal circuit for a short to ground. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 10 .
8. Repair the intermittent condition as necessary. After repairs, go to step 13 .
9. Inspect for poor connections at the harness connector of the APP sensor. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 11 .
10. Inspect for poor connections at the harness connector of the ECM. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 12 .
11. Replace the APP sensor assembly. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 13 .
12. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
13. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
14. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. DTCs P1635 or P1639 are not set.
2. The ignition switch is in the crank or run position.
3. The ignition voltage is between 7-16 volts.

1. The APP sensor 2 voltage is more than 4.75 volts.
2. All of the above conditions are present for less than 1 second.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. If one or more APP sensor DTCs are set for a single APP sensor, the following occurs: The control module will not command Reduced Engine Power mode. The control module will use the remaining two APP sensors to calculate throttle response.
5. If certain multiple APP sensor DTCs are set for more than one APP sensor, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to a predetermined value to limit the amount of throttle control. The message center displays Reduced Engine Power.
6. If all three APP sensors are out of range, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to 0 percent. The control module only allows the engine to idle. The message center displays Reduced Engine Power.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to step 4 . If no, go to next step.
3. Select the Diagnostic Trouble Code (DTC) option on the scan tool. Lightly touch and move the related APP sensor wiring harnesses and connectors while monitoring the DTC Information. Did this DTC fail this ignition cycle, during the above test? If yes, go to step 9 . If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
4. Disconnect the APP sensor harness connector. With a Digital Multimeter (DMM), measure voltage at the APP sensor 2 signal circuit. Does the DMM indicate voltage at 5.05 V? If yes, go to next step. If no, go to step 6 .
5. Connect a fused jumper between the APP sensor 3 signal circuit and the APP sensor 2 low reference circuit. With a scan tool, observe the APP sensor 3 voltage parameter. Does the scan tool indicate APP sensor 3 voltage at 0 V? If yes, go to step 11 . If no, go to step 9 .
6. Turn OFF the ignition. Disconnect the ECM harness connector containing the APP sensor 2 signal circuit. Test the APP sensor 2 signal circuit for an open. Did you find and correct the condition? If yes, go to step 15 . If no, go to next step.
7. Turn ON the ignition. Test the APP sensor 2 signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 15 . If no, go to next step.
8. Turn OFF the ignition. Disconnect the ECM harness connectors. Test the APP sensor 2, signal circuit for a short to all other APP circuits at the APP sensor harness connector. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 12 .
9. Disconnect the ECM harness connector containing the APP sensor 2 low reference circuit. Test the APP sensor 2 low reference circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 12 .
10. Repair the intermittent condition as necessary. After repairs, go to step 15 .
11. Inspect for poor connections at the harness connector of the APP sensor. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 13 .
12. Inspect for poor connections at the harness connector of the ECM. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 14 .
13. Replace the APP sensor assembly. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 15 .
14. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
15. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
16. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. DTCs P1635 or P1639 are not set.
2. The ignition switch is in the crank or run position.
3. The ignition voltage is between 7-16 volts.

1. APP sensor 3 voltage is less than 1.49 volts.
2. All of the above conditions present for less than 1 second.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. If one or more APP sensor DTCs are set for a single APP sensor, the following occurs: The control module will not command Reduced Engine Power mode. The control module will use the remaining two APP sensors to calculate throttle response.
5. If certain multiple APP sensor DTCs are set for more than one APP sensor, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to a predetermined value to limit the amount of throttle control. The message center displays Reduced Engine Power.
6. If all three APP sensors are out of range, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to 0 percent. The control module only allows the engine to idle. The message center displays Reduced Engine Power.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to step 4 . If no, go to next step.
3. Select the Diagnostic Trouble Code (DTC) option using the scan tool. Lightly touch and move the related APP wiring harnesses and connectors while monitoring the DTC Information. Did this DTC fail this ignition cycle, during the above test? If yes, go to step 8 . If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
4. Disconnect the APP sensor harness connector. With a Digital Multimeter (DMM), test for voltage at the APP sensor 3, 5-volt reference circuit. Does the DMM indicate voltage at 5.17 V? If yes, go to next step. If no, go to step 6 .
5. With a DMM, test for voltage at the APP sensor 3 signal circuit. Does the DMM indicate voltage 5.05 V? If yes, go to step 9 . If no, go to step 7 .
6. Disconnect the ECM harness connector containing the APP sensor 3, 5-volt reference circuit. Test the APP sensor 3, 5-volt reference circuit for an open. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 10 .
7. Disconnect the ECM harness connector containing the APP sensor 3 signal circuit. Test the APP sensor 3 signal circuit for a short to ground. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 10 .
8. Repair the intermittent condition as necessary. After repairs, go to step 13 .
9. Inspect for poor connections at the harness connector of the APP sensor. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 11 .
10. Inspect for poor connections at the harness connector of the ECM. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 12 .
11. Replace the APP sensor assembly. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 13 .
12. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
13. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
14. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. DTCs P1635 or P1639 are not set.
2. The ignition switch is in the crank or run position.
3. The ignition voltage is between 7-16 volts.

1. The APP sensor 3 voltage is more than 4.75 volts.
2. All of the above conditions are present for less than 1 second.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. If one or more APP sensor DTCs are set for a single APP sensor, the following occurs: The control module will not command Reduced Engine Power mode. The control module will use the remaining two APP sensors to calculate throttle response.
5. If certain multiple APP sensor DTCs are set for more than one APP sensor, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to a predetermined value to limit the amount of throttle control. The message center displays Reduced Engine Power.
6. If all three APP sensors are out of range, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to 0 percent. The control module only allows the engine to idle. The message center displays Reduced Engine Power.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to step 4 . If no, go to next step.
3. Select the Diagnostic Trouble Code (DTC) option on the scan tool. Lightly touch and move the related APP sensor wiring harnesses and connectors while monitoring the DTC Information. Did this DTC fail this ignition cycle, during the above test? If yes, go to step 9 . If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
4. Disconnect the APP sensor harness connector. With a Digital Multimeter (DMM), measure voltage at the APP sensor 3 signal circuit. Does the DMM indicate voltage at 5.05 V? If yes, go to next step. If no, go to step 6 .
5. Connect a fused jumper between the APP sensor 2 signal circuit and the APP sensor 3 low reference circuit. With a scan tool, observe the APP sensor 2 voltage parameter. Does the scan tool indicate APP sensor 2 voltage at 0 V? If yes, go to step 11 . If no, go to step 9 .
6. Turn OFF the ignition. Disconnect the ECM harness connector containing the APP sensor 3 signal circuit. Test the APP sensor 3 signal circuit for an open. Did you find and correct the condition? If yes, go to step 15 . If no, go to next step.
7. Turn ON the ignition. Test the APP sensor 3 signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 15 . If no, go to next step.
8. Turn OFF the ignition. Disconnect the ECM harness connectors. Test the APP sensor 3, signal circuit for a short to all other APP circuits at the APP sensor harness connector. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 12 .
9. Disconnect the ECM harness connector containing the APP sensor 3 low reference circuit. Test the APP sensor 3 low reference circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 12 .
10. Repair the intermittent condition as necessary. After repairs, go to step 15 .
11. Inspect for poor connections at the harness connector of the APP sensor. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 13 .
12. Inspect for poor connections at the harness connector of the ECM. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 14 .
13. Replace the APP sensor assembly. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 15 .
14. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
15. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
16. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

The engine is cranking or running.

When the engine is cranking or running, the cam sensor pulses received by the ECM do not equal 3 or 0 per 2 crankshaft revolutions.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
3. Are DTC P0335, DTC P0336, DTC P0340 or DTC P0341 set? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, go to next step.
4. Inspect for a loose CMP sensor. If the sensor cannot be tightened, the sensor must be replaced. Does the CMP sensor move without being able to be tightened? If yes, go to step 7 . If no, go to next step.
5. Remove the CMP sensor. Inspect for a broken CMP sensor casing or a rattle inside when shaken. Does the CMP sensor show any signs of physical damage? If yes, go to step 7 . If no, go to next step.
6. Remove the front engine cover. Check for excessive camshaft end play. Inspect for front engine cover damage. Inspect for timing gear misalignment or damage. See appropriate article in ENGINES. Did you find and correct the condition? If yes, go to step 8 . If no, diagnose by symptom. See appropriate article in ENGINES.
7. Replace the CMP sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
8. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
9. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

Inspect for the following items

1. A loose CMP sensor causing a variance in the sensor signal.
2. Excessive free play or damage of the timing gears.
3. The Camshaft Reference Signal Missed parameter will only increment for an intermittent. A constant failure of the CMP sensor will not cause the parameter to increment, but will set DTC P0340.

1. DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0405, P0406, P0489, P0490, P0500, P1639, P2142, P2144, and P2145 are not set.
2. The EGR valve vacuum control solenoid has been commanded to more than 70 percent.
3. The PCM is not in the Reduced Engine Power mode.
4. The BARO parameter is more than 72 kPa.
5. The Engine Speed parameter is between 610-820 RPM and is steady within 50 RPM for more than 3 seconds.
6. The ECT Sensor parameter is between 140-212°F (60-100°C).
7. The Calculated Fuel Rate parameter is between 3-20 mm 3 .
8. The Power Take Off (PTO) is disabled, if equipped.
9. The IAT Sensor parameter is more than 32°F (0°C).
10. The APP Indicated Angle parameter is less than 1 percent.
11. The Ignition 1 Signal parameter is between 11-18 volts.
12. The Vehicle Speed Sensor parameter is less than 0.25 MPH.
13. The Engine Run Time parameter is more than 5 seconds.
14. All of the above conditions are met for more than 3 seconds.

1. The ECM detects a higher than desired EGR vacuum sensor signal and a lower than expected MAF rate.
2. The above conditions are met for more than 4 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition cycle? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-138411-S09593146372002041200000) .
3. Turn OFF the ignition. Disconnect the vacuum hose from the EGR vacuum vent solenoid outlet port to the EGR vacuum sensor. Install a hand held vacuum pump on the outlet port of the EGR vacuum vent solenoid. Apply 15 in. Hg vacuum. Does the vacuum hold steady? If yes, go to step 7 . If no, go to next step.
4. Disconnect the vacuum hose from the EGR vacuum vent solenoid inlet port. Install a vacuum gauge on the inlet port of the EGR vacuum vent solenoid. Apply 15 in. Hg vacuum. The solenoid should hold vacuum. Command the EGR Vent ON with a scan tool. The EGR vacuum vent solenoid should release the vacuum to 0 in. Hg. Does the EGR vacuum vent solenoid operate as described? If yes, go to next step. If no, go to step 9 .
5. Exit the Output Control Function on the scan tool. Compare the EGR Vacuum Sensor parameter to the BARO parameter with a scan tool. Is the EGR Vacuum Sensor parameter within 4 kPa of the BARO parameter? If yes, go to next step. If no, go to step 8 .
6. Inspect for the following conditions: A stuck open EGR valve. A restriction in the exhaust system causing a high back pressure condition. Did you find and correct the condition? If yes, go to step 10 . If no, see «DIAGNOSTIC AIDS»(ref-138411-S09593146372002041200000) .
7. Replace the EGR vacuum vent solenoid. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
8. Replace the EGR vacuum sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
9. Replace the EGR valve vacuum control solenoid. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
10. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
11. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

Inspect for the following conditions

1. A stuck open EGR vacuum vent solenoid.
2. A stuck open EGR valve vacuum control solenoid.
3. Proper vacuum line connections.
4. A restriction in the exhaust system causing high back pressure.

1. The ignition is ON.
2. DTCs U1800 or U2104 are not set.

The FICM detects low supply voltage.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Do any other DTCs set? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, go to next step.
3. Turn OFF the ignition. Disconnect the FICM connectors. Turn ON the ignition. Probe the FICM power circuits with a Digital Multimeter (DMM) connected to one of the FICM ground circuits. Does the voltage measure more than 10 volts? If yes, go to step 5 . If no, go to next step.
4. Repair high resistance in the FICM power or ground circuits. After repairs, go to step 6 .
5. Replace the FICM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
6. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
7. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

The ignition is ON.

1. The ECM detects a voltage out of tolerance condition on the 5-volt reference A circuit.
2. The above condition is present for longer than 10 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
3. Visually and physically inspect the ECM and engine grounds. Ensure that the grounds are clean and secure. If a problem is found, repair as necessary. Did you find and correct the condition? If yes, go to step 12 . If no, go to next step.
4. Turn OFF the ignition. Disconnect the Accelerator Pedal Position (APP) sensor electrical connector. Turn ON the ignition, with the engine OFF. Using a Digital Multimeter (DMM), measure the voltage between the 5-volt reference circuit of the APP sensor 1 or the APP sensor 3 and the engine ground. Does the voltage measure near 5 V? If yes, go to step 6 . If no, go to next step.
5. Does the voltage measure more than 5 V? If yes, go to step 9 . If no, go to step 7 .
6. Reconnect the APP sensor. Disconnect the Fuel Rail Pressure (FRP) sensor. Using a DMM, measure the voltage between the FRP sensor 5-volt reference circuit and the engine ground. Does the voltage measure near 5 V? If yes, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM. If no, go to step 10 .
7. Monitor DMM while disconnecting the FRP sensor. If voltage changes when the sensor is disconnected, replace FRP sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Did you find and correct the condition? If yes, go to step 12 . If no, go to next step.
8. Turn OFF the ignition. Disconnect the ECM. Check the 5-volt reference circuit for the following conditions: A short to ground. A short to any low reference circuit. A short to the fuel pressure regulator control circuit. A short to the TCM MIL request circuit. A short to the ignition 1 relay control circuit. If a problem is found, repair as necessary. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 11 .
9. Turn OFF the ignition. Disconnect the ECM. Turn ON the ignition, with the engine OFF. Check the 5-volt reference circuit for a short to voltage. If a problem is found, repair as necessary. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 11 .
10. Replace the APP sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 12 .
11. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
12. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
13. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

The ignition is ON.

1. The ECM detects a voltage out of tolerance condition on the 5-volt reference 2 circuit.
2. The above condition is present for longer than 10 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
3. Visually and physically inspect the ECM and engine grounds. Ensure that the grounds are clean and secure. If a problem is found, repair as necessary. Did you find and correct the condition? If yes, go to step 12 . If no, go to next step.
4. Turn OFF the ignition. Disconnect the BARO sensor electrical connector. Turn ON the ignition, with the engine OFF. Using a Digital Multimeter (DMM), measure voltage between the 5-volt reference circuit and the engine ground. Does the voltage measure near 5 V? If yes, go to step 6 . If no, go to next step.
5. Does the voltage measure more than 5 V? If yes, go to step 9 . If no, go to step 7 .
6. Reconnect BARO sensor. Disconnect the APP sensor. Using a DMM, measure voltage between the 5-volt reference 2 circuit of APP 2 and the engine ground. Does the voltage measure near 5 V? If yes, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM. If no, go to step 10 .
7. Monitor DMM while disconnecting the following sensors: The APP sensor. The boost sensor. The EGR vacuum sensor, if applicable. If voltage changes when one of the sensors is disconnected, replace the component. Did you find and correct the condition? If yes, go to step 12 . If no, go to next step.
8. Turn OFF the ignition. Disconnect the ECM. Check the 5-volt reference circuit for the following conditions: A short to ground. A short to any low reference circuit. A short to the fuel pressure regulator control circuit. A short to the TCM MIL request circuit. A short to the ignition 1 relay control circuit. If a problem is found, repair as necessary. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 11 .
9. Turn OFF the ignition. Disconnect the ECM. Turn ON the ignition, with the engine OFF. Check the following circuits for a short to voltage: The 5-volt reference circuit. The boost sensor signal circuit. The BARO sensor signal circuit. The EGR vacuum sensor signal circuit, if applicable. If a problem is found, repair as necessary. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 11 .
10. Replace the BARO sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 12 .
11. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
12. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
13. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. The ignition is in the ON.
2. The ignition voltage is between 6-18 volts.

The voltage on the Wait To Start indicator circuit is high, near battery voltage, when the Wait To Start indicator is requested ON; or the voltage on the Wait To Start indicator control circuit is low, near 0 volts, when the Wait To Start indicator is requested OFF.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Ensure that the engine is not at full operating temperature. Observe the Wait to Start lamp while turning ON the ignition. Does the Wait to Start indicator turn ON and then turn OFF? If yes, go to next step. If no, go to step 4 .
3. The DTC is intermittent. If no additional DTCs are stored, see «DIAGNOSTIC AIDS»(ref-138411-S33505869142002050300000) . If additional DTCs were stored refer to those tables. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) .
4. Does the Wait to Start indicator stay ON? If yes, go to step 7 . If no, go to next step.
5. Disconnect the ECM connector containing the Wait to Start lamp control circuit. Turn ON the Ignition, with the engine OFF. Probe the Wait to Start indicator control circuit in the ECM harness connector with a fused jumper connected to a good ground. Does the Wait to Start lamp illuminate? If yes, go to next step. If no, go to step 8 .
6. Inspect for poor connections at ECM. Repair as necessary. Did you find and correct the condition? If yes, go to step 10 . If no, go to step 9 .
7. Inspect the control circuit of the Wait to Start indicator for a short to ground. Repair as necessary. Did you find and correct the condition? If yes, go to step 10 . If no, go to step 9 .
8. Check the Wait to Start indicator circuit for the following conditions: An open ignition 1 voltage circuit to the bulb. A malfunctioning bulb. The control circuit open or shorted to battery voltage. After repairs, go to step 10 .
9. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
10. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
11. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

A faulty bulb or the control circuit shorted to ground will cause a DTC P1643 to set.

1. DTCs U1800, U2104 or U2106 are not set.
2. The ignition is ON.

The FICM detects current through an internal driver when the driver is OFF.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Replace the FICM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
3. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
4. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

There is no external failure that can cause DTC P1658 to set. This DTC is an internal circuit failure. An intermittent or hard code will result in FICM replacement.

The ignition is ON.

The ECM is detecting an incorrect voltage level on the TCM MIL request circuit.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Connect a scan tool. Did DTC P1781 fail this ignition cycle? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
4. Turn OFF the ignition. Disconnect the TCM. Connect a Digital Multimeter (DMM) from the TCM MIL request circuit at the TCM harness connector to a good ground. Turn ON the ignition, with the engine OFF. Does the voltage measure near battery voltage? If yes, go to next step. If no, go to step 6 .
5. Test the TCM MIL request circuit for a short to voltage. Repair as necessary. Did you find and correct a condition? If yes, go to step 12 . If no, go to step 7 .
6. Test the TCM MIL request circuit for an open. Repair as necessary. Did you find and correct a condition? If yes, go to step 12 . If no, go to step 7 .
7. Leave the TCM disconnected. Connect a fused jumper wire from the TCM MIL request circuit in the TCM harness connector to a good ground. Clear the DTCs with a scan tool. Does DTC P0700 set, not setting P1781? If yes, go to next step. If no, go to step 10 .
8. Test the TCM connectors for a bad connection. Did you find and correct a condition? If yes, go to step 12 . If no, go to next step.
9. Replace the TCM. After repairs, go to step 12 .
10. Test the ECM connectors for a bad connection. Did you find and correct a condition? If yes, go to step 12 . If no, go to next step.
11. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
12. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
13. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. The ignition is ON for more than 0.5 second.
2. The EGR throttle valve vacuum control solenoid is commanded OFF.
3. The Ignition 1 Signal parameter is between 11-18 volts.

1. A low voltage condition on the control circuit of the EGR throttle valve vacuum control solenoid is detected by the ECM when the EGR throttle valve vacuum control solenoid is commanded OFF.
2. The above conditions are met for more than 4 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Turn ON the ignition, with the engine OFF. Command the EGR throttle valve solenoid ON and OFF with a scan tool. Does the EGR throttle valve vacuum control solenoid click with each command? If yes, go to next step. If no, go to step 4 .
3. Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition cycle? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
4. Disconnect the EGR throttle valve vacuum control solenoid. Turn ON the ignition, with the engine OFF. Connect a test lamp between the ignition 1 voltage circuit of the EGR throttle valve vacuum control solenoid and a good ground. Does the test lamp illuminate? If yes, go to next step. If no, go to step 6 .
5. Connect a test lamp between the control circuit of the EGR throttle valve vacuum control solenoid and the ignition 1 voltage circuit of the EGR throttle valve vacuum control solenoid. Turn ON the ignition, with the engine OFF. Command the EGR throttle valve solenoid ON and OFF with a scan tool. Does the test lamp turn ON and OFF when command with a scan tool? If yes, go to step 10 . If no, go to step 7 .
6. Inspect the Fuel HT fuse for an open. If the fuse is open, test the ignition 1 voltage circuit for a short to ground. Replace the fuse if necessary. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 10 .
7. Does the test lamp remain illuminated with each command? If yes, go to step 9 . If no, go to next step.
8. Test the control circuit of the EGR throttle valve vacuum control solenoid for an open and for high resistance. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 11 .
9. Test the control circuit of the EGR throttle valve vacuum control solenoid for a short to ground. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 11 .
10. Test for an intermittent and for a poor connection at the EGR throttle valve vacuum control solenoid. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 12 .
11. Test for an intermittent and for a poor connection at the ECM. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 13 .
12. Replace the EGR throttle valve vacuum control solenoid. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Replace the Fuel HT fuse if necessary. After repairs, go to step 14 .
13. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
14. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
15. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. The ignition is ON for more than 0.5 seconds.
2. The EGR throttle valve vacuum control solenoid is commanded ON.
3. The Ignition 1 Signal parameter is between 11-18 volts.

1. A high voltage condition on the control circuit of the EGR throttle valve vacuum control solenoid is detected by the ECM when the EGR throttle valve vacuum control solenoid is commanded ON.
2. The above conditions are met for more than 4 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Start the engine Run the engine at 1000 RPM. Command the EGR throttle valve solenoid ON and OFF with a scan tool. Does the tone of the engine change when the EGR throttle valve solenoid is commanded ON and OFF with a scan tool? If yes, go to next step. If no, go to step 5 .
3. Turn OFF the ignition. Disconnect the ECM harness connector containing the EGR throttle valve vacuum solenoid control circuit. Connect a Digital Multimeter (DMM) between the EGR throttle valve vacuum solenoid control circuit and a good ground. Set the DMM to the 10 amp scale. Turn ON the ignition with the engine OFF. Observe the DMM for 2 minutes. Does the current measure less than 0.75 A for the entire 2 minutes? If yes, go to next step. If no, go to step 9 .
4. Turn OFF the ignition. Reconnect the ECM connector. Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition cycle? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
5. Connect a test lamp between the control circuit of the EGR throttle valve vacuum control solenoid and the ignition 1 voltage circuit of the EGR throttle valve vacuum control solenoid. Command the EGR throttle valve solenoid ON and OFF with a scan tool. Does the test lamp turn ON and OFF when commanded with a scan tool? If yes, go to step 7 . If no, go to next step.
6. Test the Control circuit of the EGR throttle valve vacuum control solenoid for a short to voltage. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 8 .
7. Test for an intermittent and for a poor connection at the EGR throttle valve vacuum control solenoid. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 9 .
8. Test for an intermittent and for a poor connection at the ECM. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 10 .
9. Replace the EGR throttle valve vacuum control solenoid. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 11 .
10. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
11. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
12. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. The ignition is ON.
2. The EGR vacuum vent solenoid is commanded OFF.
3. The Ignition 1 Signal parameter is between 11-18 volts.

1. A low voltage condition on the control circuit of the EGR vacuum vent solenoid is detected by the ECM when the EGR vacuum vent solenoid is commanded OFF.
2. The above conditions are met for more than 4 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Turn ON the ignition, with the engine OFF. Command the EGR Vent ON and OFF with a scan tool. Does the EGR vacuum vent solenoid click with each command? If yes, go to next step. If no, go to step 4 .
3. Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition cycle? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
4. Disconnect the EGR vacuum vent solenoid. Turn ON the ignition, with the engine OFF. Connect a test lamp between the ignition 1 voltage circuit of the EGR vacuum vent solenoid and a good ground. Does the test lamp illuminate? If yes, go to next step. If no, go to step 6 .
5. Connect a test lamp between the control circuit of the EGR vacuum vent solenoid and the ignition 1 voltage circuit of the EGR vacuum vent solenoid. Turn ON the ignition, with the engine OFF. Command the EGR Vent ON and OFF with a scan tool. Does the test lamp turn ON and OFF when command with a scan tool? If yes, go to step 12 . If no, go to step 7 .
6. Inspect the Fuel HT fuse for an open. Is the fuse open? If yes, go to step 11 . If no, go to step 10 .
7. Does the test lamp remain illuminated with each command? If yes, go to step 9 . If no, go to next step.
8. Test the control circuit of the EGR vacuum vent solenoid for an open and for high resistance. Did you find and correct the condition? If yes, go to step 16 . If no, go to step 13 .
9. Test the control circuit of the EGR vacuum vent solenoid for a short to ground. Did you find and correct the condition? If yes, go to step 16 . If no, go to step 12 .
10. Test the ignition 1 voltage circuit for an open or high resistance. Repair as necessary. After repairs, go to step 16 .
11. Test the ignition 1 voltage circuit for a short to ground. Did you find and correct the condition? If yes, go to step 16 . If no, go to next step.
12. Test for an intermittent and for a poor connection at the EGR vacuum vent solenoid. Did you find and correct the condition? If yes, go to step 16 . If no, go to step 14 .
13. Test for an intermittent and for a poor connection at the ECM. Did you find and correct the condition? If yes, go to step 16 . If no, go to step 15 .
14. Replace the EGR vacuum vent solenoid. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 16 .
15. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
16. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
17. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. The ignition is ON for more than 0.5 seconds.
2. The EGR vacuum vent solenoid is commanded ON.
3. The Ignition 1 Signal parameter is between 11-18 volts.

1. A high voltage condition on the control circuit of the EGR vacuum vent solenoid is detected by the ECM when the EGR vacuum vent solenoid is commanded ON.
2. The above conditions are met for more than 4 seconds.

1. The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM.
2. Turn the ignition ON, with the engine OFF. Command the EGR Vent ON and OFF with a scan tool. Does the EGR vacuum vent solenoid click when commanded ON and OFF? If yes, go to next step. If no, go to step 5 .
3. Turn OFF the ignition. Disconnect the ECM harness connector containing the EGR vacuum vent solenoid control circuit. Connect a Digital Multimeter (DMM) between the EGR vacuum vent solenoid control circuit and a good ground. Set the DMM to the 10 amp scale. Turn ON the ignition with the engine OFF. Observe the DMM for 2 minutes. Does the current measure less than 0.75 A for the entire 2 minutes? If yes, go to next step. If no, go to step 9 .
4. Turn OFF the ignition. Reconnect the ECM connector. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition cycle? If yes, go to next step. If no, see «INTERMITTENT CONDITIONS»(ref-138411-S25082006642002041200000) under SELF-DIAGNOSTIC SYSTEM.
5. Connect a test lamp between the control circuit of the EGR vacuum vent solenoid and the ignition 1 voltage circuit of the EGR vacuum vent solenoid. Command the EGR Vent ON and OFF with a scan tool. Does the test lamp turn ON and OFF when commanded with a scan tool? If yes, go to step 7 . If no, go to next step.
6. Test the Control circuit of the EGR vacuum vent solenoid for a short to voltage. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 8 .
7. Test for an intermittent and for a poor connection at the EGR vacuum vent solenoid. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 9 .
8. Test for an intermittent and for a poor connection at the ECM. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 10 .
9. Replace the EGR vacuum vent solenoid. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 11 .
10. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING. After repairs, go to next step.
11. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
12. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.