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Engine Control System - 4.6l (lh2) - DTC p0420 to p0686 Cadillac SRX I

Testing & Diagnostics ~10327 words

Circuit Description

A three-way catalytic converter (TWC) controls emissions of hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx). The catalyst within the converter promotes a chemical reaction which oxidizes the HC and CO that are present in the exhaust gas. This process converts these chemicals into water vapor and carbon dioxide (CO2), and will reduce the NOx, converting the NOx into nitrogen.

The catalytic converter stores oxygen. The efficiency of the TWC is determined by the measurement of the oxygen storage capacity (OSC). The engine control module (ECM) measures the catalyst OSC by monitoring the heated oxygen sensor (HO2S) bank 1 sensor 2 and HO2S bank 2 sensor 2, during a steady state cruise. The ECM commands the air-to-fuel ratio lean and then rich for a calibrated number of cycles while monitoring the response time of the HO2S 2. The ECM then establishes an average response time from subsequent air-to-fuel ratio cycles. The difference of the average response time determines the OSC of the catalyst. If the ECM detects that this time difference is less than a calibrated value, DTC P0420 or DTC P0430 sets.

DTC Descriptors

This diagnostic procedure supports the following DTCs

  1. DTC P0420 Catalyst System Low Efficiency Bank 1
  2. DTC P0430 Catalyst System Low Efficiency Bank 2

Conditions for Running the DTC

  1. DTCs P0010, P0011, P0013, P0014, P0016, P0017, P0018, P0019, P0020, P0023, P0024, P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052, P0056, P0057, P0058, P0068, P0102, P0103, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0151, P0153, P0155, P0157, P0158, P0159, P0160, P0161, P0171, P0172, P0174, P0175, P0221, P0222, P0223, P0300-P0308, P0315, P0335, P0336, P0340, P0341, P0345, P0346, P0365, P0366, P0390, P0391, P0500, P0608, P1137, P1138, P1157, P1258, P1358, P1380, P1381, P2088, P2090-P2095, P2101, P2119, P2135, P2231, or P2234 are not set.
  2. The mass air flow (MAF) is between 11-80.3 grams per second.
  3. The engine speed is between 1,088-3,008 RPM.
  4. The engine has been running more than 10 minutes.
  5. The predicted catalyst temperature is between 644-902°C (1,191-1,656°F).
  6. The barometric pressure (BARO) is more than 74 kPa.
  7. The engine coolant temperature (ECT) is more than 62°C (143°F).
  8. The intake air temperature (IAT) is between -6°C and +200°C (+21°F and +392°F).
  9. The engine is in Closed Loop fuel control.
  10. The vehicle speed sensor (VSS) is more than 35 km/h (22 mph).
  11. The engine is at a steady cruise, a light load, with no load variation.
  12. DTC P0420 and P0430 run once within the above conditions are met for 24.8 seconds.

Conditions for Setting the DTC

  1. The powertrain control module (PCM) determines that the oxygen storage capability of the TWC has degraded to less than a calibrated threshold.
  2. The above condition exists for more than 1 second.

Action Taken When the DTC Sets

  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 the 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.

Diagnostic Aids

  1. The catalyst may have been temporarily contaminated with a chemical from an aftermarket fuel additive or fuel containing too much sulfur. The sulfur will coat the converter wash coat causing the converter performance to degrade temporarily. Driving the vehicle at highway speeds for 10 minutes will burn off the contamination. Retest the converter afterwards.
  2. Certain conditions may cause a catalytic converter to degrade. These conditions may include the following: An engine misfire High engine oil or high coolant consumption Retarded spark timing A weak spark A lean fuel mixture A rich fuel mixture A damaged oxygen sensor wiring harness
  3. Correct any condition that may cause an engine performance concern.
  4. If an intermittent condition cannot be duplicated, the information included in Freeze Frame data can be useful in determining the vehicle operating conditions when the DTC was set.
StepActionValuesYesNo
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Review the DTC information on the scan tool. Are any other DTCs set?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationGo to Step 3
3Allow the engine to reach operating temperature. Ensure Closed Loop is achieved. Increase the engine speed to 2,000 RPM for 2 minutes. Return the engine to a stabilized idle. Observe the catalyst monitor HO2S 2 voltage parameter on the scan tool for the applicable bank. Is the HO2S 2 parameter transitioning below the first specified value and above the second specified value?300 mV 650 mVGo to Step 5Go to Step 4
4CAUTION: Refer to Road Test Caution in Cautions and Notices. Clear the DTCs with a scan tool. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did DTC P0420 or P0430 set?Go to Step 5Go to Diagnostic Aids
5IMPORTANT: Verify that the three-way catalytic converter is a high quality part that meets the OEM specifications. Visually and physically inspect the three-way catalytic convertor for the following conditions: Any dents A severe discoloration caused by excessive temperatures Any internal rattles caused by loose catalyst substrate Did you find and correct the condition?Go to Step 10Go to Step 6
6Visually inspect the exhaust system for the following conditions: The exhaust system for leaks-Refer to Exhaust Leakage in Engine Exhaust. The exhaust system for a restriction-Refer to Restricted Exhaust in Engine Exhaust. Any physical damage Any loose or missing hardware The heated oxygen sensor (HO2S) 2 for the applicable bank for proper torque Did you find and correct the condition?Go to Step 10Go to Step 7
7Visually inspect the HO2S 2 at the applicable bank for the following conditions: The pigtail and the wiring harness making contact with the exhaust or any ground Any dents Did you find a condition?Go to Step 8Go to Step 9
8Replace the applicable HO2S 2 sensor. Refer to Heated Oxygen Sensor (HO2S) Replacement Bank 1 Sensor 2 or Heated Oxygen Sensor (HO2S) Replacement Bank 2 Sensor 2 . Did you complete the replacement?Go to Step 10
9NOTE: In order to avoid damaging the replacement three-way catalytic converter, correct the engine misfire or mechanical fault before replacing the three-way catalytic converter. Replace the three-way catalytic converter.Did you complete the replacement?Go to Step 10
10CAUTION: Refer to Road Test Caution in Cautions and Notices. IMPORTANT: A new catalyst may fail this test due to out-gassing of the internal matting. If this occurs, operate the vehicle at highway speeds for approximately one hour and retest. 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 the 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?Go to Step 2Go to Step 11
11Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK
CAUTION
Refer to Road Test Caution in Cautions and Notices.
IMPORTANT
Verify that the three-way catalytic converter is a high quality part that meets the OEM specifications.
NOTE
In order to avoid damaging the replacement three-way catalytic converter, correct the engine misfire or mechanical fault before replacing the three-way catalytic converter.
CAUTION
Refer to Road Test Caution in Cautions and Notices.
IMPORTANT
A new catalyst may fail this test due to out-gassing of the internal matting. If this occurs, operate the vehicle at highway speeds for approximately one hour and retest.

DTC P0420 or P0430

System Description

This diagnostic tests the evaporative emission (EVAP) system for a small leak when the key is turned OFF and the correct conditions are met.

Heat from the exhaust system is transferred into a vehicle fuel tank while the vehicle is operating. When the vehicle is turned OFF, a change in fuel tank vapor temperature occurs. In a sealed system this results in corresponding pressure changes in the fuel tank vapor space. This change is monitored by the control module using the fuel tank pressure (FTP) sensor input. The control module then makes a judgement on the integrity of the system. With a 0.51 millimeter (0.02 inches) leak in the system, the amount of pressure change observed is significantly less than that of a sealed system.

If the control module detects a pressure change less than a calibrated amount, DTC P0442 sets.

DTC Descriptor

This diagnostic procedure supports the following DTC

P0442 EVAP System Small Leak Detected

  1. DTCs P0030, P0031, P0032, P0050, P0051, P0052, P0068, P0101, P0102, P0103, P0111, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0151, P0152, P0153, P0154, P0155, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0221, P0222, P0223, P0261, P0262, P0264, P0265, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P0279, P0280, P0282, P0283, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308, P0313, P0443, P0446, P0449, P0452, P0453, P0454, P0458, P0459, P0496, P0498, P0499, P0500, P0722, P0723, P1111, P1112, P1114, P1115, P1791, P1795, P2100, P2101, P2108, P2119, P2122, P2123, P2127, P2128, P2135, P2138, P2234 are not set.
  2. The diagnostic runs once with 10-hour minimum between tests after a fail.
  3. DTC P0455 must run and PASS.
  4. The start-up intake air temperature (IAT) is between 4-30°C (39-86°F).
  5. The start-up engine coolant temperature (ECT) is less than 30°C (86°F).
  6. The start-up IAT and ECT are within 8°C (15°F).
  7. The barometric pressure (BARO) is more than 74 kPa.
  8. The ambient air temperature is between 2-32°C (36-90°F).
  9. The engine run time minimum is 10 minutes.
  10. The odometer displays more than 16 kilometers (10 miles).
  11. The vehicle has traveled more than 5 kilometers (3 miles) this trip.
  12. The ECT is more than 70°C (158°F).
  13. The fuel level is between 15-85 percent.
  14. The ignition is OFF.

The control module detects a pressure change that is less than a calibrated amount.

  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. A condition may exist where a leak in the EVAP system only exists under a vacuum condition. By using the scan tool PURGE/SEAL function to create a vacuum, seal the system and observe the FTP parameter for vacuum decay. This type of leak may be detected.
  2. To help locate intermittent leaks, use the J 41413-200 Evaporative Emission System Tester (EEST) to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the J 41413-SPT High Intensity White Light.
  3. To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT .
  4. For intermittent conditions, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-46l-lh2-troubleshooting__intermittent-conditions) .
StepActionYesNo
Schematic Reference: Evaporative Emissions (EVAP) Hose Routing Diagram
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2IMPORTANT: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. Turn the nitrogen/smoke valve to NITROGEN. Connect the nitrogen/smoke hose to the 0.5 mm (0.02 in) test orifice on the bottom-front of the J 41413-200 Evaporative Emission System Tester (EEST). Use the remote switch to activate the J 41413-200 . Align the red flag on the flow meter with the floating indicator. Use the remote switch to de-activate the J 41413-200 . Install the J 41415-40 or GE-41415-50 Fuel Tank Cap Adapter to the fuel fill pipe. See Special Tools . Remove the nitrogen/smoke hose from the test orifice and install the hose onto the J 41415-40 or GE-41415-50 . See Special Tools . Turn ON the ignition, with the engine OFF. Command the evaporative emission (EVAP) vent solenoid closed with a scan tool. Use the remote switch to introduce nitrogen and fill the EVAP system until the floating stabilizes. Compare the flow meter stable floating indicator position to the red flag. is the floating indicator below the red flag?Go to Diagnostic AidsGo to Step 3
3IMPORTANT: Ensure that the vehicle underbody temperature is similar to the ambient temperature and allow the surrounding air to stabilize before starting the diagnostic procedure. System flow will be less with higher temperatures. Turn OFF the ignition. Connect the J 41413-200 power supply clips to a known good 12-volt source. Install the J 41415-40 or GE-41415-50 to the fuel fill pipe. See Special Tools . Connect the J 41413-200 nitrogen/smoke supply hose to the J 41415-40 or GE-41415-50 . See Special Tools . Turn ON the ignition, with the engine OFF. Command the EVAP vent solenoid valve closed with a scan tool. Turn the nitrogen/smoke valve on the J 41413-200 control panel to SMOKE. Use the remote switch to introduce smoke into the EVAP system. Use the J 41413-VLV EVAP Service Port Vent Fitting to open the EVAP service port. Remove the J 41413-VLV once smoke is observed. Continue to introduce smoke into the EVAP system for an additional 60 seconds. Inspect the entire EVAP system for exiting smoke with the J 41413-SPT High Intensity White Light. Continue to introduce smoke at 15-second intervals until the leak source has been located. Did you locate and repair a leak source?Go to Step 5Go to Step 4
4Disconnect the J 41415-40 or GE-41415-50 from the fuel fill pipe. See Special Tools . Install the fuel fill cap to the fuel fill pipe. Connect the J 41413-200 nitrogen/smoke supply hose to the EVAP service port. Use the remote switch to introduce smoke into the EVAP system. Inspect the entire EVAP system for exiting smoke with the J 41413-SPT . Continue to introduce smoke at 15-second intervals until the leak source has been located. Did you locate and repair a leak source?Go to Step 5Go to Diagnostic Aids
5IMPORTANT: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. Turn the nitrogen/smoke valve to NITROGEN. Connect the nitrogen/smoke hose to the 0.5 mm (0.02 in) test orifice on the bottom-front of the J 41413-200 . Use the remote switch to activate the J 41413-200 . Align the red flag on the flow meter with the floating indicator. Use the remote switch to de-activate the J 41413-200 . Install the J 41415-40 or GE-41415-50 to the fuel fill pipe. See Special Tools . Remove the nitrogen/smoke hose from the test orifice and install the hose onto the J 41415-40 or GE-41415-50 . See Special Tools . Turn ON the ignition, with the engine OFF. Command the EVAP vent solenoid valve closed with a scan tool. Use the remote switch to introduce nitrogen and fill the EVAP system until the floating indicator stabilizes. Compare the flow meter stable floating indicator position to the red flag. Is the floating indicator below the red flag?Go to Step 6Go to Step 2
6Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK
IMPORTANT
Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize.
IMPORTANT
Ensure that the vehicle underbody temperature is similar to the ambient temperature and allow the surrounding air to stabilize before starting the diagnostic procedure. System flow will be less with higher temperatures.
IMPORTANT
Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize.

DTC P0442

An ignition voltage is supplied directly to the evaporative emission (EVAP) canister purge solenoid valve. The EVAP canister purge solenoid valve is pulse width modulated (PWM). The scan tool displays the amount of ON time as a percentage. The control module controls the EVAP canister purge solenoid valve ON time by grounding the control circuit via an internal switch called a driver. The control module monitors the status of the driver. If the control module detects an open circuit on the control circuit while the driver is commanded OFF, this DTC sets.

This diagnostic procedure supports the following DTC

P0443 EVAP Purge Solenoid Control Circuit

  1. DTCs P0458, P0459 are not set.
  2. The ignition is ON.

The control module detects an open circuit on the EVAP purge solenoid valve control circuit with the driver commanded 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.

Test Description

The number below refers to the step number on the diagnostic table.

  1. 5: This step tests the control modules ability to supply a ground to the EVAP purge solenoid valve.
StepActionValuesYesNo
Schematic Reference Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Turn ON the ignition, with the engine OFF. Command the evaporative emission (EVAP) canister purge solenoid valve to 50 percent and then to 0 percent with a scan tool. Do you hear or feel a clicking from the EVAP purge solenoid valve when the valve is commanded to 50 percent?Go to Step 3Go to Step 4
3Observe 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 the 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?Go to Step 8Go to Intermittent Conditions
4Turn OFF the ignition. Disconnect the EVAP canister purge solenoid valve harness connector. Turn ON the ignition, with the engine OFF. Probe the ignition 1 voltage circuit of the EVAP canister purge solenoid valve with a test lamp connected to a good ground. Does the test lamp illuminate?Go to Step 5Go to Step 9
5Connect a test lamp between the control circuit of the EVAP canister purge solenoid valve and the ignition 1 voltage circuit of the EVAP canister purge solenoid valve. Command the EVAP canister purge solenoid valve to 50 percent with a scan tool. Does the test lamp illuminate or pulse when the EVAP purge solenoid valve is commanded to 50 percent?Go to Step 7Go to Step 6
6Test the control circuit of the EVAP canister purge solenoid valve for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 12Go to Step 8
7Test for an intermittent and for a poor connection at the EVAP canister purge solenoid valve. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 12Go to Step 10
8Test for an intermittent and for a poor connection at the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 12Go to Step 11
9Repair the open in the ignition 1 voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 12
10Replace the EVAP canister purge solenoid valve. Refer to Evaporative Emission (EVAP) Canister Purge Solenoid Valve Replacement . Did you complete the replacement?Go to Step 12
11Replace the engine control module (ECM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 12
12Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the 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?Go to Step 2Go to Step 13
13Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK

DTC P0443

This DTC tests the evaporative emission (EVAP) system for a restricted or blocked EVAP vent path. The control module commands the EVAP canister purge solenoid valve Open and the EVAP canister vent solenoid valve Closed. This allows vacuum to be applied to the EVAP system. Once a calibrated vacuum level has been reached, the control module commands the EVAP canister purge solenoid valve Closed and the EVAP canister vent solenoid valve Open. The control module monitors the fuel tank pressure (FTP) sensor for a decrease in vacuum. If the vacuum does not decrease to near 0 inches H2O in a calibrated time, this DTC sets.

The following table illustrates the relationship between the ON and OFF states, and the Open or Closed states of the EVAP canister purge and vent solenoid valves.

Control Module CommandEVAP Canister Purge Solenoid ValveEVAP Canister Vent Solenoid Valve
ONOpenClosed
OFFClosedOpen

DTC P0446

This diagnostic procedure supports the following DTC

DTC P0446 EVAP Vent System Performance

  1. DTC P0449, P0451, P0452, P0453, P0454, P0498, P0499 are not set.
  2. The EVAP canister purge solenoid valve must be active.
  3. The engine is running.

The fuel tank pressure is less than -7 inches H2O with the EVAP canister vent solenoid valve commanded 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. An intermittent condition could be caused by a damaged EVAP vent housing, a temporary blockage at the EVAP vent solenoid valve inlet, or a pinched vent hose. A blockage in the vent system will also cause a poor fuel fill problem.
  2. For intermittent conditions, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-46l-lh2-troubleshooting__intermittent-conditions) .
StepActionValuesYesNo
Schematic Reference: Evaporative Emissions (EVAP) Hose Routing Diagram
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Inspect the evaporative emission (EVAP) system for the following conditions: A damaged EVAP vent solenoid valve-Refer to Evaporative Emission (EVAP) Canister Vent Solenoid Valve Replacement . A pinched EVAP vent hose A damaged EVAP canister-Refer to Evaporative Emission (EVAP) Canister Replacement . Did you find and correct the condition?Go to Step 13Go to Step 3
3Turn OFF the ignition. Disconnect the purge line from the EVAP purge solenoid valve. Turn ON the ignition, with the engine OFF. Observe the Fuel Tank Pressure Sensor parameter with a scan tool. Is the fuel tank pressure sensor parameter within the specified range?1 to +1 in H2OGo to Step 4Go to Step 8
4IMPORTANT: DO NOT exceed the specified value in this step. Exceeding the specified value may produce incorrect test results. Turn OFF the ignition. Connect the EVAP purge pipe. Connect the J 41413-200 Evaporative Emission System Tester (EEST) power supply clips to a known good 12-volt source. Install the J 41415-40 or GE-41415-50 Fuel Tank Cap Adapter to the fuel fill pipe. See Special Tools . Connect the fuel fill cap to the J 41415-40 or GE-41415-50 . See Special Tools . Connect the J 41413-200 nitrogen/smoke supply hose to the J 41415-40 or GE-41415-50 . See Special Tools . Turn ON the ignition, with the engine OFF. Command the EVAP vent solenoid valve Closed with a scan tool. Turn the nitrogen/smoke valve on the J 41413-200 control panel to NITROGEN. Use the remote switch to pressurize the EVAP system to the first specified value. Observe the fuel tank pressure sensor in H2O with a scan tool. Command the EVAP vent solenoid valve Open with a scan tool. Is the fuel tank pressure sensor parameter less than the second specified value?5 in H2O 1 in H2OGo to Diagnostic AidsGo to Step 5
5Disconnect the EVAP vent hose from the EVAP vent solenoid valve. Is the fuel tank pressure sensor parameter less than the specified value?1 in H2OGo to Step 11Go to Step 6
6Disconnect the EVAP vent hose from the EVAP canister. Is the fuel tank pressure sensor parameter less than the specified value?1 in H2OGo to Step 7Go to Step 12
7Repair the pinched or restricted EVAP vent hose. Did you complete the repair?Go to Step 13
8Test for poor connections at the harness connector of the fuel tank pressure (FTP) sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 9
9Test the FTP sensor low reference circuit for an open or high resistance. Did you find and correct the condition?Go to Step 13Go to Step 10
10Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement . Did you complete the replacement?Go to Step 13
11Replace the EVAP vent solenoid valve. Refer to Evaporative Emission (EVAP) Canister Vent Solenoid Valve Replacement . Did you complete the replacement?Go to Step 13
12Replace the EVAP canister. Refer to Evaporative Emission (EVAP) Canister Replacement . Did you complete the replacement?Go to Step 13
13Turn OFF the ignition. Disconnect the purge line from the EVAP purge solenoid valve. Turn ON the ignition, with the engine OFF. Observe the Fuel Tank Pressure Sensor parameter with a scan tool. Is the fuel tank pressure sensor parameter within the specified range?1 to +1 in H2OGo to Step 14Go to Step 2
14IMPORTANT: DO NOT exceed the specified value in this step. Exceeding the specified value may produce incorrect test results. Turn OFF the ignition. Reconnect all disconnected components. Connect the J 41413-200 to the fuel fill pipe. Turn ON the ignition, with the engine OFF. Command the EVAP vent solenoid valve Closed with a scan tool. Turn the nitrogen/smoke valve on the J 41413-200 control panel to NITROGEN. Use the remote switch to pressurize the EVAP system to the first specified value. Observe the fuel tank pressure sensor in H2O with a scan tool. Command the EVAP vent solenoid valve Open with a scan tool. Is the fuel tank pressure sensor parameter less than the second specified value?5 in H2O 1 in H2OGo to Step 15Go to Step 2
15Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK
IMPORTANT
DO NOT exceed the specified value in this step. Exceeding the specified value may produce incorrect test results.
IMPORTANT
DO NOT exceed the specified value in this step. Exceeding the specified value may produce incorrect test results.

DTC P0446

An ignition voltage is supplied to the evaporative emission (EVAP) canister vent solenoid valve. The control module grounds the EVAP canister vent solenoid valve control circuit to close the valve by means of an internal switch called a driver. The scan tool displays the commanded state of the EVAP canister vent solenoid valve as ON or OFF. The control module monitors the status of the driver. If the control module detects an open circuit on the control circuit when the driver is commanded OFF, this DTC sets.

The following table illustrates the relationship between the ON and OFF states, and the OPEN or CLOSED states of the EVAP canister vent solenoid valve.

Control Module CommandEVAP Canister Vent Solenoid Valve Position
ONClosed
OFFOpen

DTC P0449

This diagnostic procedure supports the following DTC

DTC P0449 EVAP Vent Solenoid Control Circuit

  1. DTC P0443, P0446, P0449, P0455, P0458, P0459, P0496, P0499 are not set.
  2. The ignition is ON.

The control module detects an open condition on the control circuit when the driver is commanded 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.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Turn ON the ignition, with the engine OFF. Command the evaporative emission (EVAP) vent solenoid valve ON and OFF with a scan tool. Do you hear or feel a click from the EVAP canister vent solenoid valve when the valve is commanded ON and OFF?Go to Step 3Go to Step 4
3Observe 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 the 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?Go to Step 8Go to Intermittent Conditions
4Turn OFF the ignition. Disconnect the EVAP vent solenoid valve. Turn ON the ignition, with the engine OFF. Probe the battery positive voltage circuit of the EVAP vent solenoid valve with a test lamp connected to a good ground. Does the test lamp illuminate?Go to Step 5Go to Step 9
5Connect a test lamp between the control circuit of the EVAP vent solenoid valve and battery positive voltage circuit of the EVAP vent solenoid valve. Command the EVAP vent solenoid valve ON with a scan tool. Does the test lamp illuminate?Go to Step 7Go to Step 6
6Test the control circuit of the EVAP canister vent solenoid valve for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 12Go to Step 8
7Test for an intermittent and for a poor connection at the EVAP vent solenoid valve. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 12Go to Step 10
8Test for an intermittent and for a poor connection at the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 12Go to Step 11
9Repair the open in the battery positive voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 12
10Replace the EVAP canister vent solenoid valve. Refer to Evaporative Emission (EVAP) Canister Vent Solenoid Valve Replacement . Did you complete the replacement?Go to Step 12
11Replace the engine control module (ECM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 12
12Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the 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?Go to Step 2Go to Step 13
13Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK

DTC P0449

The fuel tank pressure (FTP) sensor measures the difference between the air pressure or vacuum in the evaporative emission (EVAP) system and the outside air pressure. The control module supplies a 5-volt reference and a low reference circuit to the FTP sensor. The FTP sensor signal circuit voltage varies depending on EVAP system pressure or vacuum. If the FTP sensor signal voltage becomes fixed while driving, or fluctuates more than a calibrated amount at idle, this DTC sets.

The following table illustrates the relationship between the FTP sensor signal voltage and the EVAP system pressure/vacuum.

FTP Sensor Signal VoltageFuel Tank Pressure
High, Approximately 1.5 Volts or MoreNegative Pressure/Vacuum
Low, Approximately 1.5 Volts or LessPositive Pressure

DTC P0451

This diagnostic procedure supports the following DTC

DTC P0451 Fuel Tank Pressure (FTP) Sensor Performance

  1. DTCs P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052, P0056, P0057, P0058, P0068, P0101, P0102, P0103, P0111, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0136, P0137, P0138, P0139, P0140, P0141, P0150, P0151, P0152, P0153, P0154, P0155, P0156, P0157, P0158, P0159, P0160, P0161, P0201, P0202, P0203, P0204, P0205, P0206, P0221, P0222, P0223, P0308, P0313, P0443, P0446, P0449, P0452, P0453, P0454, P0458, P0459, P0496, P0498, P0499, P0506, P0507, P1271, P1277, P1278, P1282, P1283, P1511, P1516, P1519, P1523, P1526, P1530, P1551, P2100, P2101, P2107, P2119, P2122, P2123, P2127, P2128, P2138, P2176 are not set.
  2. The engine is idling.
  3. The FTP has varied at least once before idling. OR
  4. The vehicle speed is more than 45 km/h (28 mph).
  5. The canister is purging.
  6. The FTP is more than 0.02 volts.
  1. The FTP varies more than 0.37 mm Hg (0.2 in H2O) for 5 seconds at idle. OR
  2. The FTP varies less than 0.02 volts for 5 seconds while driving.
  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.
StepActionValue(s)YesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Idle the engine for 1 minute. Monitor the DTC information using the scan tool. Did DTC P0651 fail this ignition?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationGo to Step 3
3Turn ON the ignition, with the engine OFF. Disconnect the fuel tank pressure (FTP) sensor. Measure the voltage from the 5-volt reference circuit of the FTP sensor to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems. Is the voltage within the specified value?4.9-5.1 VGo to Step 4Go to Step 6
4Turn OFF the ignition. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the FTP sensor and the signal circuit of the FTP sensor. Turn ON the ignition, with the engine OFF. Observe the FTP sensor voltage with a scan tool. Is the Fuel Tank Pressure sensor parameter within the specified value?4.9-5.1 VGo to Step 5Go to Step 8
5Measure the voltage from the 5-volt reference circuit to the low reference circuit with a DMM. Is the voltage within the specified value?4.9-5.1 VGo to Step 9Go to Step 7
6Test the 5-volt reference circuit for an open circuit or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 10
7Test the low reference circuit of the FTP sensor for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 10
8Test the signal circuit for the following conditions: High resistance Damage Corrosion Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 10
9Test for an intermittent and for a poor connection at the FTP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 11
10Test for an intermittent and for a poor connection at the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 12
11Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement . Did you complete the replacement?Go to Step 13
12Replace the engine control module (ECM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 13
13IMPORTANT: DO NOT exceed the specified value in this step. Exceeding this specified value may produce incorrect test results. Connect the J 41413-200 Evaporative Emission System Tester (EEST) to the fuel fill pipe. Turn the nitrogen/smoke valve to NITROGEN. Seal the EVAP Purge/Seal function with a scan tool. Pressurize the evaporative emission (EVAP) system to the specified value. Observe the fuel tank pressure sensor parameter with a scan tool. Does the fuel tank pressure sensor parameter remain constant?5 in H2OGo to Step 14Go to Step 2
14Observe the fuel tank pressure sensor parameter with a scan tool. Is the difference between the scan tool fuel tank pressure sensor parameter and the J 41413-200 gage within the specified value?1 in H2OGo to Step 15Go to Step 2
15Observe the fuel tank pressure parameter with the engine OFF. Increase the EVAP purge solenoid valve to 100 percent. Does the pressure decrease?Go to Step 16Go to Step 2
16Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the 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?Go to Step 2Go to Step 17
17Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK
IMPORTANT
DO NOT exceed the specified value in this step. Exceeding this specified value may produce incorrect test results.

DTC P0451

The fuel tank pressure (FTP) sensor measures the difference between the air pressure or vacuum in the evaporative emission (EVAP) system, and the outside air pressure. The control module supplies a 5-volt reference and a low reference circuit to the FTP sensor. The FTP sensor signal circuit voltage varies depending on EVAP system pressure or vacuum. If the FTP sensor signal voltage goes below a calibrated value, this DTC sets.

The following table illustrates the relationship between the FTP sensor signal voltage and the EVAP system pressure/vacuum.

FTP Sensor Signal VoltageFuel Tank Pressure
High, Approximately 1.5 Volts or MoreNegative Pressure/Vacuum
Low, Approximately 1.5 Volts or LessPositive Pressure

DTC P0452

This diagnostic procedure supports the following DTC

DTC P0452 FTP Sensor Circuit Low Voltage

The engine is running.

The FTP sensor voltage variation is less than 0.02 volts for 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.

The number below refers to the step number on the diagnostic table.

  1. 2: If DTC P0651 is set, the 5-volt reference circuit may be shorted to ground.
StepActionValue(s)YesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Idle the engine for 1 minute. Monitor the DTC information using the scan tool. Did DTC P0651 fail this ignition?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationGo to Step 3
3Observe the Fuel Tank Pressure sensor parameter with a scan tool. Is the Fuel Tank Pressure sensor parameter less than the specified value?0.1 VGo to Step 5Go to Step 4
4Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the 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?Go to Step 5Go to Intermittent Conditions
5Turn OFF the ignition. Disconnect the fuel tank pressure (FTP) sensor harness connector. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the FTP sensor and the signal circuit of the FTP sensor. Turn ON the ignition, with the engine OFF. Observe the FTP voltage with a scan tool. Is the Fuel Tank Pressure sensor parameter within the specified value?4.9-5.1 VGo to Step 8Go to Step 6
6Test the 5-volt reference circuit for an open circuit or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 12Go to Step 7
7Test the FTP signal circuit for the following conditions: A short to ground An open High resistance Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 12Go to Step 9
8Test for an intermittent and for a poor connection at the FTP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 12Go to Step 10
9Test for an intermittent and for a poor connection at the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 12Go to Step 11
10Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement . Did you complete the replacement?Go to Step 12
11Replace the engine control module (ECM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 12
12Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the 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?Go to Step 2Go to Step 13
13Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK

DTC P0452

The fuel tank pressure (FTP) sensor measures the difference between the air pressure or vacuum in the evaporative emission (EVAP) system, and the outside air pressure. The control module supplies a 5-volt reference and a low reference circuit to the FTP sensor. The FTP sensor signal circuit voltage varies depending on EVAP system pressure or vacuum. If the FTP sensor signal voltage increases above a calibrated value, this DTC sets.

The following table illustrates the relationship between the FTP sensor signal voltage and the EVAP system pressure/vacuum.

FTP Sensor Signal VoltageFuel Tank Pressure
High, Approximately 1.5 Volts or MoreNegative Pressure/Vacuum
Low, Approximately 1.5 Volts or LessPositive Pressure

DTC P0453

This diagnostic procedure supports the following DTC

DTC P0453 FTP Sensor Circuit High Voltage

The engine is running.

The FTP sensor voltage is more than 4.9 volts 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.

The number below refers to the step number on the diagnostic table.

  1. 2: If DTC P0651 is set, the 5-volt reference circuit may be shorted to a voltage.
StepActionValue(s)YesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Idle the engine for 1 minute. Monitor the DTC information using the scan tool. Did DTC P0651 fail this ignition?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationGo to Step 3
3Turn ON the ignition, with the engine OFF. Observe the Fuel Tank Pressure sensor parameter with a scan tool. Is the Fuel Tank Pressure sensor parameter more than the specified value?4.3 VGo to Step 5Go to Step 4
4Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the 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?Go to Step 5Go to Intermittent Conditions
5Turn OFF the ignition. Disconnect the fuel tank pressure (FTP) sensor harness connector. Turn ON the ignition, with the engine OFF. Observe the Fuel Tank Pressure sensor parameter with a scan tool. Did the scan tool indicate that the FTP sensor voltage is more than the specified value?4.3 VGo to Step 6Go to Step 7
6Test the signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 10
7Test the low reference circuit of the FTP sensor for a short to voltage, with a DMM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 8
8Test the low reference circuit for an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 9
9Test for an intermittent and for a poor connection at the FTP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 11
10Test for an intermittent and for a poor connection at the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 12
11Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement . Did you complete the replacement?Go to Step 13
12Replace the engine control module (ECM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 13
13Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the 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?Go to Step 2Go to Step 14
14Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK

DTC P0453

The fuel tank pressure (FTP) sensor measures the difference between the air pressure or vacuum in the evaporative emission (EVAP) system and the outside air pressure. The control module supplies a 5-volt reference and a low reference circuit to the FTP sensor. The FTP sensor signal circuit voltage varies depending on EVAP system pressure or vacuum. If the FTP sensor signal voltage goes above or below a calibrated value, this DTC sets.

The following table illustrates the relationship between the FTP sensor signal voltage and the EVAP system pressure/vacuum.

FTP Sensor Signal VoltageFuel Tank Pressure
High, Approximately 1.5 Volts or MoreNegative Pressure/Vacuum
Low, Approximately 1.5 Volts or LessPositive Pressure

DTC P0454

This diagnostic procedure supports the following DTC

P0454 Fuel Tank Pressure (FTP) Sensor Circuit Intermittent

The engine is running.

The fuel tank pressure sensor voltage is more than 4.95 or less than 0.045 volts for one 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.

Conditions for Clearing the 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. Clear the DTC with a scan tool.

The DTC is designed to detect an intermittent short to ground or a short to voltage on the FTP signal circuit. An open circuit on the 5-volt reference, the signal circuit or the low reference circuit may also set this DTC.

StepActionValuesYesNo
Schematic Reference: Evaporative Emissions (EVAP) Hose Routing Diagram
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Are DTCs P0452, P0453 or P0651 also set?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationGo to Diagnostic Aids

DTC P0454

The control module tests the evaporative emission (EVAP) system for a large leak. The control module monitors the fuel tank pressure (FTP) sensor signal to determine the EVAP system vacuum level. When the conditions for running are met, the control module commands the EVAP canister purge solenoid valve OPEN and the EVAP canister vent solenoid valve CLOSED. This allows engine vacuum to enter the EVAP system. At a calibrated time, or vacuum level, the control module commands the EVAP canister purge solenoid valve closed, sealing the system, and monitors the FTP sensor input in order to determine the EVAP system vacuum level. If the system is unable to achieve the calibrated vacuum level, or the vacuum level decreases too rapidly, this DTC sets.

The following table illustrates the relationship between the ON and OFF states, and the OPEN or CLOSED states of the EVAP canister purge and vent solenoid valves.

Control Module CommandEVAP Canister Purge Solenoid ValveEVAP Canister Vent Solenoid Valve
ONOpenClosed
OFFClosedOpen

DTC P0455

This diagnostic procedure supports the following DTC

P0455 EVAP System Large Leak Detected

  1. DTCs P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052, P0056, P0057, P0058, P0068, P0101, P0102, P0103, P0111, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0136, P0137, P0138, P0139, P0140, P0141, P0150, P0151, P0152, P0153, P0154, P0155, P0156, P0157, P0158, P0159, P0160, P0161, P0201, P0202, P0203, P0204, P0205, P0206, P0221, P0222, P0223, P0308, P0313, P0443, P0446, P0449, P0452, P0453, P0454, P0458, P0459, P0496, P0498, P0499, P0506, P0507, P1271, P1277, P1278, P1282, P1283, P1511, P1516, P1519, P1523, P1526, P1530, P1551, P2107, P2108, P2100, P2101, P2119, P2122, P2123, P2127, P2128, P2138, P2176 are not set.
  2. The engine run time is more than 2 minutes.
  3. The ignition voltage is between 10-18 volts.
  4. The barometric pressure (BARO) is more than 70 kPa.
  5. The fuel level is between 15-85 percent.
  6. The engine coolant temperature (ECT) is more than 75°C (167°F).
  7. The vehicle speed is less than 8 km/h (5 mph).
  8. The FTP is between -1.7 and +0.1 kPa (-7.0 and +0.4 in H2O).
  9. The FTP must have varied at least once.
  10. The vehicle is operating in Closed Loop.

The EVAP system is not able to achieve or maintain vacuum during the diagnostic test.

  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. To help locate intermittent leaks, use the J 41413-200 Evaporative Emissions System Tester (EEST) to introduce smoke into the EVAP System. Move all EVAP components while observing smoke with the J 41413-SPT High Intensity White Light. Introducing smoke in 15-second intervals will allow less pressure into the EVAP System. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.
  2. A loose, incorrect, missing, or damaged fuel fill cap may cause this DTC to set.
  3. A temporary blockage in the EVAP purge solenoid valve, purge pipe or EVAP canister could cause an intermittent condition. Inspect and repair any restriction in the EVAP system.
  4. A condition may exist where a leak in the EVAP system only exists under a vacuum condition. By using the scan tool Purge/Seal function to create a vacuum, sealing the system and observing the FTP parameter for vacuum decay, this type of leak may be detected.
  5. To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT .
  6. Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.
  7. For intermittent conditions, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-46l-lh2-troubleshooting__intermittent-conditions) .

The number below refers to the step number on the diagnostic table.

  1. 7: A normal operating FTP sensor should increase above 5, and stop between 6-7 inches of H2O.
StepActionValuesYesNo
Schematic Reference: Evaporative Emissions (EVAP) Hose Routing Diagram
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Inspect the evaporative emission (EVAP) system for the following conditions: A loose, missing, or damaged service port Schrader valve A loose, incorrect, missing, or damaged fuel fill cap A damaged EVAP purge solenoid valve Raise the vehicle on a hoist. Refer to Lifting and Jacking the Vehicle in General Information. Inspect the EVAP system for the following conditions: Any disconnected, improperly routed, kinked, or damaged EVAP pipes and hoses A damaged EVAP canister vent solenoid valve or EVAP canister Did you find and correct the condition?Go to Step 16Go to Step 3
3IMPORTANT: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. Turn OFF the ignition. Connect the J 41413-200 Evaporative Emissions System Tester (EEST) power supply clips to a known good 12-volt source. Turn the nitrogen/smoke valve to nitrogen. Connect the nitrogen/smoke hose to the 0.5 mm (0.02 in) test orifice on the bottom-front of the J 41413-200 . Use the remote switch to activate the J 41413-200 . Align the red flag on the flow meter with the floating indicator. Use the remote switch to de-activate the J 41413-200 . Install the J 41415-40 or GE-41415-50 Fuel Tank Cap Adapter to the fuel fill pipe. See Special Tools . Install the fuel fill cap to the J 41415-40 or GE-41415-50 . See Special Tools . Remove the nitrogen/smoke hose from the test orifice and install the hose onto the J 41415-40 or GE-41415-50 . See Special Tools . Turn ON the ignition, with the engine OFF. Command the EVAP canister vent solenoid valve closed with a scan tool. Use the remote switch to introduce nitrogen and fill the EVAP System until the floating indicator stabilizes. Compare the flow meter stable floating indicator position to the red flag. Is the floating indicator below the red flag?Go to Step 6Go to Step 4
4IMPORTANT: Ensure that the vehicle underbody temperature is similar to the ambient temperature, and allow the surrounding air to stabilize before starting the diagnostic procedure. System flow will be less with higher temperatures. Turn OFF the ignition. Connect the J 41413-200 power supply clips to a known good 12-volt source. Install the J 41415-40 or GE-41415-50 to the fuel fill pipe. See Special Tools . Connect the J 41413-200 nitrogen/smoke supply hose to the J 41415-40 or GE-41415-50 . See Special Tools . Turn ON the ignition, with the engine OFF. Command the EVAP canister vent solenoid valve Closed with a scan tool. Turn the nitrogen/smoke valve on the J 41413-200 control panel to SMOKE. Use the remote switch to introduce smoke into the EVAP system. Use the J 41413-VLV EVAP Service Port Vent Fitting to open the EVAP service port. Remove the J 41413-VLV once smoke is observed. Continue to introduce smoke into the EVAP System for an additional 60 seconds. Inspect the entire EVAP System for exiting smoke with the J 41413-SPT High Intensity White Light. Continue to introduce smoke at 15-second intervals until the leak source has been located. Did you locate and repair a leak source?Go to Step 16Go to Step 5
5Disconnect the J 41415-40 or GE-41415-50 from the fuel fill pipe. See Special Tools . Install the fuel fill cap to the fuel fill pipe. Connect the J 41413-200 nitrogen/smoke supply hose to the EVAP service port. Use the remote switch to introduce smoke into the EVAP System. Inspect the entire EVAP System for exiting smoke with the J 41413-SPT . Continue to introduce smoke at 15-second intervals until the leak source has been located Did you locate and repair a leak source?Go to Step 16Go to Step 6
6Use the remote switch to stop introducing smoke. Install the J 41415-40 or GE-41415-50 to the fuel fill pipe. See Special Tools . Connect the J 41413-200 nitrogen/smoke supply hose and vehicle fuel fill cap to the J 41415-40 or GE-41415-50 . See Special Tools . Command the EVAP canister vent solenoid valve Open with a scan tool. Compare the fuel tank pressure sensor parameter with a scan tool to the J 41413-200 pressure/vacuum gage. Is the difference between the scan tool fuel tank pressure sensor parameter and the pressure/vacuum gage on the J 41413-200 within the specified value?1 in H2OGo to Step 7Go to DTC P0451
7Seal the EVAP system using the EVAP Purge/Seal function with a scan tool. Turn the nitrogen/smoke valve on the J 41413-200 control panel to NITROGEN. Use the J 41413-200 to pressurize the EVAP system to the first specified value. Observe the fuel tank pressure sensor parameter with a scan tool. Is the fuel tank pressure sensor parameter more than the second specified value?10 in H2O 5 in H2OGo to Step 8Go to DTC P0451
8Use the remote switch to stop introducing nitrogen into the EVAP system. Increase the EVAP canister purge solenoid valve to 100 percent. Is the fuel tank pressure sensor parameter less than the specified value?1 in H2OGo to Diagnostic AidsGo to Step 9
9Disconnect the EVAP canister purge pipe from the EVAP purge solenoid valve. Is the fuel tank pressure sensor parameter less than the specified value?1 in H2OGo to Step 13Go to Step 10
10Disconnect the EVAP purge pipe at the EVAP canister. Is the fuel tank pressure sensor parameter less than the specified value?1 in H2OGo to Step 14Go to Step 11
11Disconnect the EVAP vapor pipe at the EVAP canister. Is the fuel tank pressure sensor parameter less than the specified value?1 in H2OGo to Step 15Go to Step 12
12Repair the pinched or obstructed EVAP vapor pipe. Did you complete the repair?Go to Step 16
13Replace the EVAP canister purge solenoid valve. Refer to Evaporative Emission (EVAP) Canister Purge Solenoid Valve Replacement . Did you complete the replacement?Go to Step 16
14Repair the restriction in the EVAP purge pipe. Did you complete the repair?Go to Step 16
15Replace the EVAP canister. Refer to Evaporative Emission (EVAP) Canister Replacement . Did you complete the replacement?Go to Step 16
16IMPORTANT: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. Turn the nitrogen/smoke valve to NITROGEN. Connect the nitrogen/smoke hose to the 0.5 mm (0.02 in) test orifice on the bottom-front of the J 41413-200 . Use the remote switch to activate the J 41413-200 . Align the red flag on the flow meter with the floating indicator. Use the remote switch to de-activate the J 41413-200 . Install the J 41415-40 or GE-41415-50 to the fuel fill pipe. See Special Tools . Remove the nitrogen/smoke hose from the test orifice and install the hose onto the J 41415-40 or GE-41415-50 . See Special Tools . Turn ON the ignition, with the engine OFF. Command the EVAP vent solenoid valve Closed with a scan tool. Use the remote switch to introduce nitrogen and fill the EVAP system until the floating stabilizes. Compare the flow meter stable floating indicator position to the red flag. Is the floating indicator below the red flag?5 in H2OGo to Step 17Go to Step 3
17Observe the J 41413-200 pressure/vacuum gage. Increase the EVAP canister purge solenoid valve to 100 percent. Does the pressure decrease?Go to Step 18Go to Step 9
18Compare the fuel tank pressure sensor parameter with a scan tool to the J 41413-200 . Is the difference between the scan tool fuel tank pressure sensor parameter and the pressure/vacuum gage on the J 41413-200 within the specified value?1 in H2OGo to Step 19Go to DTC P0451
19Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK
IMPORTANT
Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize.
IMPORTANT
Ensure that the vehicle underbody temperature is similar to the ambient temperature, and allow the surrounding air to stabilize before starting the diagnostic procedure. System flow will be less with higher temperatures.
IMPORTANT
Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize.

DTC P0455

An ignition voltage is supplied directly to the evaporative emission (EVAP) canister purge solenoid valve. The EVAP canister purge solenoid valve is pulse width modulated (PWM). The scan tool displays the amount of ON time as a percentage. The control module controls the EVAP canister purge solenoid valve ON time by grounding the control circuit via an internal switch called a driver. The control module monitors the status of the driver. If the control module detects low voltage on the control circuit when the driver is commanded OFF, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0458 Evaporative Emission (EVAP) Purge Solenoid Control Circuit Low Voltage

  1. DTCs P0443, P0459 are not set.
  2. The ignition is ON.

The control module detects low voltage on the control circuit of the EVAP canister purge solenoid valve when the driver is commanded 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.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Turn ON the ignition, with the engine OFF. Command the evaporative emission (EVAP) canister purge solenoid valve to 50 percent and then to 0 percent with a scan tool. Do you hear or feel a clicking from the EVAP purge solenoid valve when the valve is commanded to 50 percent?Go to Step 3Go to Step 4
3Observe 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 the 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?Go to Step 4Go to Intermittent Conditions
4Test the control circuit of the EVAP canister purge solenoid valve for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 7Go to Step 5
5Test for an intermittent and for a poor connection at the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 7Go to Step 6
6Replace the engine control module (ECM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 7
7Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the 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?Go to Step 2Go to Step 8
8Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK

DTC P0458

An ignition voltage is supplied directly to the evaporative emission (EVAP) canister purge solenoid valve. The EVAP canister purge solenoid valve is pulse width modulated (PWM). The scan tool displays the amount of ON time as a percentage. The control module monitors the status of the driver. The control module controls the EVAP canister purge solenoid valve ON time by grounding the control circuit via an internal switch called a driver. If the control module detects voltage on the control circuit when the driver is commanded ON, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0459 Evaporative Emission (EVAP) Purge Solenoid Control Circuit High Voltage

  1. DTCs P0443, P0458 are not set.
  2. The ignition is ON.

The actual state of the control circuit does not match the commanded 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.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Turn ON the ignition, with the engine OFF. Command the evaporative emission (EVAP) canister purge solenoid valve to 50 percent and then to 0 percent with a scan tool. Do you hear or feel a clicking from the EVAP canister purge solenoid valve when the valve is commanded to 50 percent?Go to Step 3Go to Step 4
3Review 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 the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze/Frame Failure Records. Does the DTC fail this ignition?Go to Step 7Go to Intermittent Conditions
4Turn OFF the ignition. Disconnect the EVAP canister purge solenoid valve. Turn ON the ignition, with the engine OFF Probe the control circuit of the EVAP canister purge solenoid valve with a test lamp that is connected to a good ground. Does the test lamp illuminate?Go to Step 5Go to Step 6
5Test the control circuit of the EVAP canister purge solenoid valve for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 10Go to Step 7
6Inspect for an intermittent and for a poor connection at the EVAP canister purge solenoid valve. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 10Go to Step 8
7Inspect for an intermittent and for a poor connection at the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 10Go to Step 9
8Replace the EVAP canister purge solenoid valve. Refer to Evaporative Emission (EVAP) Canister Purge Solenoid Valve Replacement . Did you complete the replacement?Go to Step 10
9Replace the engine control module (ECM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 10
10Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the 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?Go to Step 2Go to Step 11
11Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK

DTC P0459

This DTC tests for undesired intake manifold vacuum flow to the evaporative emission (EVAP) system. The control module seals the EVAP system by commanding the EVAP canister purge solenoid valve Closed and the EVAP canister vent solenoid valve Closed. The control module monitors the fuel tank pressure (FTP) sensor to determine if a vacuum is being drawn on the EVAP system. If vacuum in the EVAP system is more than a predetermined value within a predetermined time, this DTC sets.

The following table illustrates the relationship between the ON and OFF states, and the Open or Closed states of the EVAP canister purge solenoid and vent solenoid valves.

Control Module CommandEVAP Canister Purge Solenoid ValveEVAP Canister Vent Solenoid Valve
ONOpenClosed
OFFClosedOpen

DTC P0496

This diagnostic procedure supports the following DTC

DTC P0496 EVAP System Flow During Non-Purge

  1. DTCs P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052, P0056, P0057, P0058, P0068, P0101, P0102, P0103, P0111, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0136, P0137, P0138, P0139, P0140, P0141, P0150, P0151, P0152, P0153, P0154, P0155, P0156, P0157, P0158, P0159, P0160, P0161, P0201, P0202, P0203, P0204, P0205, P0206, P0221, P0222, P0223, P0308, P0313, P0443, P0446, P0449, P0452, P0453, P0454, P0458, P0459, P0496, P0498, P0499, P0506, P0507, P1271, P1277, P1278, P1282, P1283, P1511, P1516, P1519, P1523, P1526, P1530, P1551, P2107, P2108, P2100, P2101, P2119, P2122, P2123, P2127, P2128, 2138, P2176 are not set.
  2. The ignition voltage is between 10-18 volts.
  3. The fuel tank level is between 15-85 percent.
  4. The barometric pressure (BARO) is more than 70 kPa.
  5. The vehicle speed sensor (VSS) is less than 8 km/h (5 mph).
  6. The engine run time is more than 10 minutes.
  7. The engine coolant temperature (ECT) is more than 70°C (158°F).
  8. The intake air temperature (IAT) is more than 3°C (38°F).

The control module detects vacuum during a non-purge condition.

  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.

An intermittent condition could be caused by an improperly installed or damaged EVAP canister purge solenoid valve or a temporary sticking of the EVAP canister purge solenoid valve. Inspect for debris in the EVAP system. For intermittent conditions refer to Intermittent Conditions .

StepActionValuesYesNo
Schematic Reference: Evaporative Emissions (EVAP) Hose Routing Diagram
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Start the engine. Seal the evaporative emission (EVAP) system using the Purge/Seal function with a scan tool. Observe the fuel tank pressure (FTP) sensor parameter with a scan tool. Is the FTP sensor parameter within the specified value?1 to +1 H2OGo to Diagnostic AidsGo to Step 3
3Is DTC P0651 also set?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationGo to Step 4
4Turn OFF the ignition. Disconnect the EVAP purge pipe from the EVAP canister purge solenoid valve. Turn ON the ignition, with the engine OFF. Observe the FTP sensor parameter with a scan tool. Is the FTP sensor parameter within the specified range?1 to +1 H2OGo to Step 5Go to Diagnostic Aids
5Replace the EVAP canister purge solenoid valve. Refer to Evaporative Emission (EVAP) Canister Purge Solenoid Valve Replacement . Did you complete the replacement?Go to Step 6
6Connect all EVAP hardware that was previously disconnected. Start and idle the engine. Seal the EVAP system using the Purge/Seal function with a scan tool. Observe the fuel tank pressure sensor parameter with a scan tool. Is the fuel tank pressure sensor parameter within the specified range?1 to +1 H2OGo to Step 7Go to Step 2
7Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK

DTC P0496

Battery voltage is supplied directly to the evaporative emission (EVAP) canister vent solenoid valve. The control module grounds the EVAP canister vent solenoid valve control circuit to close the valve by means of an internal switch called a driver. The scan tool displays the commanded state of the EVAP canister vent solenoid valve as ON or OFF. The control module monitors the status of the driver. If the control module detects low voltage on the control circuit when the driver is commanded OFF, this DTC sets.

The following table illustrates the relationship between the ON and OFF states, and the OPEN or CLOSED states of the EVAP canister vent solenoid valve.

Control Module CommandEVAP Canister Vent Solenoid Valve Position
ONClosed
OFFOpen

DTC P0498

This diagnostic procedure supports the following DTC

DTC P0498 Evaporative Emission (EVAP) Vent Solenoid Control Circuit Low Voltage

  1. DTC P0443, P0446, P0449, P0455, P0458, P0459, P0496, P0499 are not set.
  2. The ignition is ON.

The control module detects low voltage on the control circuit when the driver is commanded 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.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Turn ON the ignition, with the engine OFF. Command the evaporative emission (EVAP) canister vent solenoid valve ON and OFF with a scan tool. Do you hear or feel a click from the EVAP canister vent solenoid valve when the valve is commanded ON and OFF?Go to Step 3Go to Step 4
3Observe 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 the 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?Go to Step 4Go to Intermittent Conditions
4Turn OFF the ignition. Disconnect the EVAP canister vent solenoid valve. Turn ON the ignition, with the engine OFF. Probe the battery positive voltage circuit of the EVAP canister vent solenoid valve with a test lamp connected to a good ground. Does the test lamp illuminate?Go to Step 5Go to Step 7
5Test the control circuit of the EVAP canister vent solenoid valve for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 9Go to Step 6
6Test for an intermittent and for a poor connection at the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 9Go to Step 8
7Repair the battery positive voltage circuit of the EVAP vent solenoid valve for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Replace the fuse as necessary. Did you complete the repair?Go to Step 9
8Replace the engine control module (ECM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 9
9Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the 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?Go to Step 2Go to Step 10
10Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK

DTC P0498

Battery voltage is supplied to the evaporative emission (EVAP) canister vent solenoid valve. The control module grounds the EVAP canister vent solenoid valve control circuit to close the valve by means of an internal switch called a driver. The scan tool displays the commanded state of the EVAP canister vent solenoid valve as ON or OFF. The control module monitors the status of the driver. If the control module detects voltage on the control circuit when the driver is commanded ON, this DTC sets.

The following table illustrates the relationship between the ON and OFF states, and the OPEN or CLOSED states of the EVAP canister vent solenoid valve.

Control Module CommandEVAP Canister Vent Solenoid Valve Position
ONClosed
OFFOpen

DTC P0499

This diagnostic procedure supports the following DTC

DTC P0499 Evaporative Emission (EVAP) Vent Solenoid Control Circuit High Voltage

  1. DTC P0443, P0446, P0449, P0455, P0458, P0459, P0496, P0498 are not set.
  2. The ignition is ON.

The actual state of the control circuit does not match the commanded 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.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Turn ON the ignition, with the engine OFF. Command the evaporative emission (EVAP) canister vent solenoid valve ON and OFF with a scan tool. Do you hear or feel a click from the EVAP canister vent solenoid valve when the valve is commanded ON and OFF?Go to Step 3Go to Step 4
3Observe 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 the 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?Go to Step 4Go to Intermittent Conditions
4Turn OFF the ignition. Disconnect the EVAP canister vent solenoid valve. Turn ON the ignition, with the engine OFF. Probe the EVAP canister vent solenoid valve control circuit of the EVAP canister vent solenoid valve with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors in Wiring Systems. Does the test lamp illuminate?Go to Step 5Go to Step 6
5Test the control circuit of the EVAP canister vent solenoid valve for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 10Go to Step 7
6Test for an intermittent and for a poor connection at the EVAP canister vent solenoid valve. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 10Go to Step 8
7Test for an intermittent and for a poor connection at the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 10Go to Step 9
8Replace the EVAP canister vent solenoid valve. Refer to Evaporative Emission (EVAP) Canister Purge Solenoid Valve Replacement . Did you complete the replacement?Go to Step 10
9Replace the engine control module (ECM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 10
10Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the 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?Go to Step 2Go to Step 11
11Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK

DTC P0499

The throttle actuator control (TAC) motor is controlled by the engine control module (ECM). The DC motor located in the throttle body drives the throttle plate. In order to decrease idle speed, the ECM commands the throttle closed, which reduces air flow into the engine. In order to increase idle speed, the ECM commands the throttle plate open, which allows more air flow into the engine. If the actual idle RPM does not match the desired idle RPM within a calibrated time, DTC P0506 sets.

This diagnostic procedure supports the following DTC

DTC P0506 Idle Speed Low

  1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0122, P0123, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0270, P0271, P0273, P0274, P0276, P0277, P0279, P0280, P0282, P0283, P0351, P0352, P0353, P0354, P0355, P0356, P0357, P0358, P0638, P1106, P1107, P2100, P2101, P2108, P2119, P2122, P2123, P2127, P2128, P2135, P2138, or P2176 are not set.
  2. The engine is operating.
  3. The engine coolant temperature (ECT) is more than -7°C (+19°F).
  4. The ECT is less than 120°C (248°F).
  5. The vehicle speed is 0 km/h (0 mph).
  6. DTC P0506 runs continuously once the above conditions are met.
  1. The actual idle speed is 100 RPM lower than the desired idle speed.
  2. The above condition is present for more 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.

The number below refers to the step number on the diagnostic table.

  1. 2: This test determines whether the engine can achieve the commanded RPM.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Start the engine. With a scan tool, command the engine speed up to 1,500 RPM, down to 500 RPM, and up to 1,500 RPM. Exit the RPM control function. Does the actual engine speed correspond to the desired engine speed, within 100 RPM, with each command?Go to Intermittent ConditionsGo to Step 3
3Inspect for any condition that can reduce idle speed by increasing engine load. Examples include: Incorrect torque converter clutch (TCC) operation Accessories that require additional torque to operate Restricted exhaust Mechanical conditions that limit engine speed Did you complete the action?Go to Step 4
4Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the 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?Go to Step 2Go to Step 5
5Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK

DTC P0506

The throttle actuator control (TAC) motor is controlled by the engine control module (ECM). The DC motor located in the throttle body drives the throttle plate. In order to decrease idle speed, the ECM commands the throttle closed, which reduces air flow into the engine. In order to increase idle speed, the ECM commands the throttle plate open, which allows more air flow into the engine. If the actual idle RPM does not match the desired idle RPM within a calibrated time, DTC P0507 sets.

This diagnostic procedure supports the following DTC

DTC P0507 Idle Speed High

  1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0122, P0123, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0270, P0271, P0273, P0274, P0276, P0277, P0279, P0280, P0282, P0283, P0351, P0352, P0353, P0354, P0355, P0356, P0357, P0358, P0638, P1106, P1107, P2100, P2101, P2108, P2119, P2122, P2123, P2127, P2128, P2135, P2138, or P2176 are not set.
  2. The engine is operating.
  3. The engine coolant temperature (ECT) is more than -7°C (+19°F).
  4. The ECT is less than 120°C (248°F).
  5. The vehicle speed is 0 km/h (0 mph).
  6. DTC P0507 runs continuously once the above conditions are met.
  1. The actual idle speed is 200 RPM greater than the desired idle speed.
  2. The above condition is present for more than 11 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.

The number below refers to the step number on the diagnostic table.

  1. 2: This test determines whether the engine can achieve the commanded RPM.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Start the engine. Command the engine speed up to 1,500 RPM, down to 500 RPM, and up to 1,500 RPM with a scan tool. Exit the RPM control function. Does the actual engine speed correspond to the desired engine speed, within 100 RPM with each command?Go to Intermittent ConditionsGo to Step 3
3Inspect for the following conditions: Vacuum leaks Excessive deposits in the throttle body A faulty positive crankcase ventilation (PCV) valve Did you find and correct the condition?Go to Step 4
4Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the 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?Go to Step 2Go to Step 5
5Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK

DTC P0507

Description

This diagnostic applies to internal microprocessor integrity conditions within the engine control module (ECM). This diagnostic also addresses if the ECM is not programmed.

This diagnostic procedure supports the following DTCs

  1. DTC P0601 Control Module Read Only Memory (ROM)
  2. DTC P0602 Control Module Not Programmed
  3. DTC P0604 Control Module Random Access Memory (RAM)
  4. DTC P0606 Control Module Internal Performance
  1. DTC P0601 The ignition is ON. DTC P0601 runs continuously.
  2. DTC P0602 runs continuously.
  3. DTC P0604 The ignition is ON. DTC P0604 runs once per ignition cycle.
  4. DTC P0606 The ignition is ON. DTC P0606 runs continuously.
  1. DTC P0601-The ECM detects read only memory (ROM) errors for more than 1 second.
  2. DTC P0602-The ECM detects that programming is incomplete for more than 1 second.
  3. DTC P0604-The ECM detects that random access memory (RAM) errors for more than 1 second.
  4. DTC P0606-The ECM detects an internal condition for more than 1 second.

Actions Taken When the 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.
  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.

The numbers below refer to the step numbers on the diagnostic table.

  1. 3: A DTC P0602 indicates the ECM is not programmed.
  2. 5: Attempt to program the ECM. If the ECM fails to program a second time, replace the ECM.
StepActionYesNo
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 3Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Turn ON the ignition, with the engine OFF. Observe the DTC information with a scan tool. Does the scan tool display DTC P0686, P0687, P0689, or P0690?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationGo to Step 3
3Is DTC P0602 set?Go to Step 4Go to Step 6
4Program the engine control module (ECM). Refer to Service Programming System (SPS) in Programming and Setup. Does DTC P0602 reset?Go to Step 5Go to Step 7
5Ensure that all tool connections are secure. Ensure the programming equipment is operating correctly. Ensure the correct software and the correct calibration is used. Attempt to program the ECM. Refer to Service Programming System (SPS) in Programming and Setup. Does DTC P0602 reset?Go to Step 6Go to Step 7
6Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 7
7Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC run and pass?Go to Step 8Go to Step 3
8Observe the Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK

DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610

The engine control module (ECM) provides ignition voltage to the coil side of the fuel pump relay whenever the engine is cranking or running. The control module enables the fuel pump relay as long as the engine is cranking or running, and crankshaft reference pulses are received. If no crankshaft reference pulses are received, the control module de-energizes the fuel pump.

The fuel pump relay control circuit is pulled up to 2.5 volts within the ECM using a bypass resistor that is connected internally to ignition voltage. This resistor allows the ECM to detect a high voltage condition if the fuel pump control circuit is open when the pump relay is not commanded ON. The control module monitors the voltage on the fuel pump relay control circuit. If the ECM detects a low voltage condition on the control circuit with the engine cranking or running, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0628 Fuel Pump Relay Control Circuit Low Voltage

  1. The engine speed is more than 80 RPM.
  2. The engine controls ignition relay voltage is between 10-18 volts.
  3. The ECM has commanded the fuel pump relay ON and OFF at least once during the ignition cycle.
  4. DTC P0628 runs continuously once the above conditions have been met.
  1. The ECM detects the voltage on the fuel pump relay control circuit is less than 2.21 volts.
  2. The condition exists for less than 1 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. The circuit status parameter changes from OK to Fault if there is a condition with the circuit or a connection.
  2. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-46l-lh2-troubleshooting__intermittent-conditions) .

The number below refers to the step number on the diagnostic table.

  1. 4: This step verifies that the control module is providing voltage to the fuel pump relay.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Turn ON the ignition, with the engine OFF. Command the fuel pump ON and OFF with a scan tool. Does the fuel pump relay turn ON and OFF with each command?Go to Step 3Go to Step 4
3Observe 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 the 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?Go to Step 4Go to Intermittent Conditions
4Turn OFF the ignition. Disconnect the fuel pump relay. Turn ON the ignition, with the engine OFF. Probe the control circuit of the fuel pump relay with a test lamp connected to the engine control module (ECM) housing. Command the fuel pump ON and OFF with a scan tool. Does the test lamp turn ON and OFF?Go to Step 6Go to Step 5
5Test the control circuit of the fuel pump relay for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 8Go to Step 7
6Replace the fuel pump relay. Did you complete the replacement?Go to Step 8
7Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 8
8Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the 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?Go to Step 2Go to Step 9
9Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK

DTC P0628

The engine control module (ECM) provides ignition voltage to the coil side of the fuel pump relay whenever the engine is cranking or running. The control module enables the fuel pump relay as long as the engine is cranking or running, and crankshaft reference pulses are received. If no crankshaft reference pulses are received, the control module turns OFF the fuel pump.

The fuel pump relay control circuit is pulled up to 2.5 volts within the ECM using a bypass resistor that is connected internally to ignition voltage. This resistor allows the ECM to detect a high voltage condition if the fuel pump control circuit is open when the pump relay is not commanded ON. The control module monitors the voltage on the fuel pump relay control circuit. If the ECM detects a high voltage condition on the fuel pump relay control circuit, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0629 Fuel Pump Relay Control Circuit High Voltage

  1. The engine speed is 0 RPM.
  2. The ignition is ON, with the engine OFF.
  3. The engine controls ignition relay voltage is more than 10.5 volts.
  4. The above conditions are met for more than 1 second.

OR

  1. The engine speed is more than 80 RPM.
  2. The engine controls ignition relay voltage is more than 10.5 volts.
  3. The above conditions are met for more than 1 second.
  4. DTC P0629 runs continuously once the above conditions have been met.
  1. The ECM detects the voltage on the fuel pump relay control circuit is more than 2.79 volts with the ignition ON and the engine OFF.
  2. The condition exists for less than 1 second.

OR

  1. The ECM detects the voltage on the fuel pump relay control circuit is more than 2.79 volts when the following occurs: The engine is cranking or running. The ECM commands the fuel pump relay OFF. The ECM turns OFF the fuel pump relay control circuit for 8 ms and monitors the fuel pump relay control circuit for voltage. The ECM performs this test up to 5 times an ignition cycle.
  2. The condition exists for less than 0.5 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. The circuit status parameter changes from OK to Fault if there is a condition with the circuit or a connection.
  2. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-46l-lh2-troubleshooting__intermittent-conditions) .

The numbers below refer to the step numbers on the diagnostic table.

  1. 4: This step verifies that the control module is providing voltage to the fuel pump relay.
  2. 5: This step tests for an open in the ground circuit to the fuel pump relay.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Turn ON the ignition, with the engine OFF. Command the fuel pump ON and OFF with a scan tool. Does the fuel pump relay turn ON and OFF with each command?Go to Step 3Go to Step 4
3Observe 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 the 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?Go to Step 4Go to Intermittent Conditions
4Turn OFF the ignition. Disconnect the fuel pump relay. Turn ON the ignition, with the engine OFF. Probe the control circuit of the fuel pump relay with a test lamp connected to the engine control module (ECM) housing. Command the fuel pump ON and OFF with a scan tool. Does the test lamp turn ON and OFF when commanded?Go to Step 5Go to Step 6
5Connect a test lamp between the control circuit of the fuel pump relay and the ground circuit of the fuel pump relay. Command the fuel pump ON and OFF with a scan tool. Does the test lamp turn ON and OFF when commanded?Go to Step 7Go to Step 9
6Test the control circuit of the fuel pump relay for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 12Go to Step 8
7Test for an intermittent and for a poor connection at the fuel pump relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 12Go to Step 10
8Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 12Go to Step 11
9Repair the open ground circuit of the fuel pump relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 12
10Replace the fuel pump relay. Did you complete the replacement?Go to Step 12
11Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 12
12Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the 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?Go to Step 2Go to Step 13
13Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK

DTC P0629

The engine control module (ECM) opens the throttle blades by applying a pulse width modulated voltage to the throttle valve motor. The ECM reverses the polarity on the throttle valve motor control circuits in order to close the throttle blades. The ECM increases the pulse width as necessary to open the throttle blades. The ECM monitors the throttle position (TP) sensors 1 and 2 to determine the actual blade position. If the ECM detects the required pulse width modulation (PWM) to move the throttle blade exceeds a predetermined value, DTC P0638 sets.

This diagnostic procedure supports the following DTC

DTC P0638 Throttle Actuator Control (TAC) Command Performance

  1. The ignition is ON.
  2. The reduced engine power is active.
  3. DTC P0638 runs continuously once the above conditions are met.

The required PWM to move the throttle blade is at 100 percent for more than 1.2 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 and/or the Failure Records.
  3. The control module commands the TAC system to operate in the Reduced Engine Power mode.
  4. A message center or an indicator displays Reduced Engine Power.
  5. Under certain conditions the control module commands the engine OFF.
  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. Inspect for a condition in which the throttle valves may have been held open.
  2. Inspect for conditions in which ice may have formed in the throttle bore.
  3. The throttle valves are spring loaded to a slightly open position. This is referred to as the rest position.
  4. The throttle valves should move to the open and closed position without binding under the normal spring pressure.
  5. The throttle should NOT be free to move open or closed WITHOUT spring pressure.
  6. The scan tool has the ability to operate the throttle control system using the TP function located in the TAC System menu. This function will operate the throttle valve through the entire range in order to determine if the throttle body and system operate correctly.
  7. For intermittent conditions, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-46l-lh2-troubleshooting__intermittent-conditions) .
StepActionValue(s)YesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Observe the DTC information. Is DTC P0689 also set?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationGo to Step 3
3Observe the DTC information. Are DTCs P0122, P0123, P0222, P0223 also set?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationGo to Step 4
4IMPORTANT: The throttle valves are spring loaded in a slightly open position and should move in either direction without binding. The throttle valves should always be under spring pressure. Turn OFF the ignition. Visually inspect the throttle body for the following conditions: Throttle valves that are NOT in the rest position Throttle valves that are binding open or closed Throttle valves that are free to move open or closed WITHOUT spring pressure Did you find any of these conditions with the throttle body?Go to Step 15Go to Step 5
5IMPORTANT: Disconnecting the throttle body connector will cause additional codes to set. Disconnect the throttle body harness connector. Turn ON the ignition, with the engine OFF. Measure the voltage of the throttle actuator control (TAC) motor control 1 and TAC motor control 2 circuits of the throttle actuator motor with a DMM connected to ground. Is the voltage less than the specified value for both circuits?2 VGo to Step 6Go to Step 8
6Turn OFF the ignition. Allow the engine control module (ECM) to completely power down. This may take several minutes and can be verified by the loss of communication with the scan tool. Connect the DMM between the TAC motor control 1 circuit and a good ground. Using the min/max function, select the proper voltage range and record the maximum voltage with a DMM. Turn ON the ignition. Does the DMM indicate maximum voltage above the specified value?2 VGo to Step 7Go to Step 9
7Turn OFF the ignition. Allow the ECM to completely power down. This may take several minutes and can be verified by the loss of communication with the scan tool. Connect the DMM between the TAC motor control 2 circuit and a good ground. Using the min/max function, select the proper voltage range and record the maximum voltage with a DMM. Turn ON the ignition. Does the DMM indicate maximum voltage above the specified value?2 VGo to Step 11Go to Step 10
8Test the TAC motor control circuit that measured above the specified value for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 17Go to Step 16
9Test the TAC motor control 1 circuit for an open or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 17Go to Step 13
10Test the TAC motor control 2 circuit for an open or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 17Go to Step 13
11IMPORTANT: The DMM and test leads must be calibrated to 0 ohms to prevent misdiagnosis. Refer to the DMM User Manual for the calibration procedure. Turn OFF the ignition. Disconnect the ECM connector containing the TAC motor control circuits. Measure the resistance of the TAC motor control 1 and TAC motor control 2 circuits between the ECM connector and the throttle body connector. Refer to Circuit Testing in Wiring Systems. Is the resistance less than the specified value?4 ohmsGo to Step 13Go to Step 14
12Test for an intermittent and for a poor connection at the throttle body connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 17Go to Step 15
13Test for an intermittent and for a poor connection at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 17Go to Step 16
14Repair the TAC motor control circuit with the high resistance. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 17
15Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement . Did you complete the replacement?Go to Step 17
16Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 17
17Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the 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?Go to Step 2Go to Step 18
18Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK
IMPORTANT
The throttle valves are spring loaded in a slightly open position and should move in either direction without binding. The throttle valves should always be under spring pressure.
IMPORTANT
Disconnecting the throttle body connector will cause additional codes to set.
IMPORTANT
The DMM and test leads must be calibrated to 0 ohms to prevent misdiagnosis. Refer to the DMM User Manual for the calibration procedure.

DTC P0638

The engine control module (ECM) provides a 5-volt reference to the following sensors

  1. The manifold absolute pressure (MAP) sensor
  2. The accelerator pedal position (APP) sensor 1
  3. The fuel level sensor 2

The ECM monitors voltage on the 5-volt reference circuit. If the ECM detects that the voltage on the 5-volt reference circuit is outside a calibrated range, DTC P0641 will set.

This diagnostic procedure supports the following DTC

DTC P0641 5-Volt Reference 1 Circuit

  1. The ignition is ON.
  2. DTC P0641 runs continuously once the above condition is met.

The ECM detects a voltage that is out of range on the 5-volt reference circuit for more than 1 second.

  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.

The number below refers to the step number on the diagnostic table.

  1. 5: This step will determine if the APP sensor 1 is at fault, or if another device or circuit condition is at fault.
StepActionValuesYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Observe 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 the 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?Go to Step 3Go to Intermittent Conditions
3Turn OFF the ignition. Disconnect the accelerated pedal position (APP) sensor electrical connector. Turn ON the ignition, with the engine OFF. Measure the voltage from the 5-volt reference circuit of the APP sensor 1 harness connector to a good ground with a DMM. Is the voltage within the specified range?4.8-5.2 VGo to Step 5Go to Step 4
4Is the voltage more than the specified value?5.2 VGo to Step 8Go to Step 6
5Connect the APP sensor electrical connector. Disconnect the manifold absolute pressure (MAP) sensor. Measure the voltage from the 5-volt reference circuit of the MAP sensor harness connector to a good ground with a DMM. Is the voltage within the specified range?4.8-5.2 VGo to Intermittent ConditionsGo to Step 9
6Monitor the DMM while disconnecting all other devices connected to this 5-volt reference circuit one at a time. If the voltage changes when one of the components is disconnected, replace the component. Refer to the appropriate replacement procedure. Was a component replaced?Go to Step 11Go to Step 7
7Test this 5-volt reference circuit for a short to ground or a short to any sensor low reference circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct a condition?Go to Step 11Go to Step 10
8Turn ON the ignition, with the engine OFF. Test the following circuits for a short to voltage: All circuits on this 5-volt reference circuit The MAP sensor signal circuit Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct a condition?Go to Step 11Go to Step 10
9Replace the APP sensor. Refer to Accelerator Pedal Assembly Replacement in Adjustable Pedals Assembly. Did you complete the replacement?Go to Step 11
10Replace the engine control module (ECM). Refer to Control Module References in Computer/Integrating System for replacement, setup, and programming. Did you complete the replacement?Go to Step 11
11Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the 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?Go to Step 2Go to Step 12
12Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK

DTC P0641

The malfunction indicator lamp (MIL) is located on the instrument panel cluster (IPC). The MIL informs the driver that an emission system fault has occurred and that the engine control system requires service. The control module monitors the MIL control circuit for conditions that are incorrect for the commanded state of the MIL. If the control module detects an improper voltage on the MIL control circuit, DTC P0650 will set.

This diagnostic procedure supports the following DTC

DTC P0650 Malfunction Indicator Lamp (MIL) Control Circuit

The engine is running.

The control module detects that the commanded state of the MIL driver and the actual state of the control circuit do not match 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.

The numbers below refer to the step numbers on the diagnostic table.

  1. 6: This step tests for a short to ground in the MIL control circuit. With the engine control module (ECM) disconnected and the ignition ON, the MIL should be OFF.
  2. 7: This step tests for a short to voltage on the MIL control circuit. With the fuse removed, there should be less than 1 volt on the MIL control circuit.
StepActionValuesYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Engine Control Module (ECM) Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Turn ON the ignition, with the engine OFF. Is the instrument cluster completely inoperative?Go to Symptoms - Instrument Panel, Gages and Console in Instrument Panel, Gages, and ConsoleGo to Step 3
3Turn ON the ignition, with the engine OFF. Command the malfunction indicator lamp (MIL) ON and OFF with a scan tool. Does the MIL turn ON and OFF when commanded with a scan tool?Go to Step 4Go to Step 5
4Observe 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 the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Does the DTC fail this ignition?Go to Step 6Go to Intermittent Conditions
5Inspect the fuse that supplies voltage to the cluster. Is the fuse open?Go to Step 13Go to Step 6
6Turn OFF the ignition. Disconnect the engine control module (ECM). Turn ON the ignition. Is the MIL OFF?Go to Step 7Go to Step 12
7Remove the fuse that supplies voltage to the instrument panel cluster (IPC). Measure the voltage from the MIL control circuit to a good ground. Is the voltage less than the specified value?1 VGo to Step 8Go to Step 14
8Turn OFF the ignition. Install the fuse that supplies voltage to the IPC. Turn ON the ignition, with the engine OFF. Connect a 3-amp fused jumper wire between the MIL control circuit of the ECM and a good ground. Is the MIL illuminated?Go to Step 11Go to Step 9
9Test the MIL control circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct a condition?Go to Step 17Go to Step 10
10Test for an intermittent and for a poor connection at the IPC. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 17Go to Step 15
11Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 17Go to Step 16
12Test for a short to ground in the MIL control circuit. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 17Go to Step 15
13Test all circuits and components that use this voltage supply for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 17Go to Step 15
14Repair the short to voltage in the MIL control circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 17
15Replace the IPC. Refer to Instrument Panel Cluster (IPC) Replacement in Instrument Panel, Gages, and Console. Did you complete the replacement?Go to Step 17
16Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 17
17Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the 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?Go to Step 2Go to Step 18
18Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK

DTC P0650

The engine control module (ECM) provides a 5-volt reference to the following sensors

  1. The throttle position (TP) sensors 1 and 2
  2. The accelerator pedal position (APP) sensor 2
  3. The fuel level sensor 1
  4. The air conditioning (A/C) refrigerant
  5. The fuel tank pressure (FTP) sensor
  6. The engine oil pressure (EOP) sensor

The ECM monitors voltage on the 5-volt reference circuit. If the ECM detects that the voltage on the 5-volt reference circuit is outside a calibrated range, DTC P0651 will set.

This diagnostic procedure supports the following DTC

DTC P0651 5-Volt Reference 2 Circuit

The ignition is ON.

The ECM detects a voltage that is out of range on the 5-volt reference circuit for more than 1 second.

  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.

The number below refers to the step number on the diagnostic table.

  1. 5: This step will determine if the throttle body is at fault, or if another device or circuit condition is at fault.
StepActionValuesYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Observe 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 the 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?Go to Step 3Go to Intermittent Conditions
3Turn OFF the ignition. Disconnect the throttle body electrical connector. Turn ON the ignition, with the engine OFF. Measure the voltage from the 5-volt reference circuit of the throttle position (TP) sensors 1 and 2 of the throttle body harness connector to a good ground with a DMM. Is the voltage within the specified range?4.8-5.2 VGo to Step 5Go to Step 4
4Is the voltage more than the specified value?5.2 VGo to Step 8Go to Step 6
5Connect the throttle body electrical connector. Disconnect the A/C refrigerant pressure sensor. Measure the voltage from the 5-volt reference circuit of the A/C refrigerant pressure sensor to a good ground with a DMM. Is the voltage within the specified range?4.8-5.2 VGo to Step 9Go to Step 10
6Monitor the DMM while disconnecting all other devices connected to this 5-volt reference circuit one at a time. If voltage changes when one of the above components are disconnected, replace the component. Refer to the appropriate replacement procedure. Was a component replaced?Go to Step 12Go to Step 7
7Test the 5-volt reference circuit for a short to ground or for a short to any sensor low reference circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct a condition?Go to Step 12Go to Step 9
8Turn ON the ignition, with the engine OFF. Test the following circuits for a short to voltage: All circuits on this 5-volt reference circuit The fuel tank pressure (FTP) sensor signal circuit Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct a condition?Go to Step 12Go to Step 9
9Test this 5-volt reference circuit for a short to the throttle actuator control (TAC) motor control 1 or 2 circuits. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct a condition?Go to Step 12Go to Step 11
10Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement . Did you complete the replacement?Go to Step 12
11Replace the engine control module (ECM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 12
12Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the 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?Go to Step 2Go to Step 13
13Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK

DTC P0651

The main relay is a normally open relay. The relay armature is held in the open position by spring tension. Battery positive voltage is supplied directly to the relay coil and the armature contact at all times. The engine control module (ECM) supplies the ground path to the relay coil control circuit via an internal integrated circuit, called an output driver module (ODM). One ODM output control is configured to operate as a low side driver for the main relay. The low side driver for the main relay also incorporates a fault detection circuit, which is continuously monitored by the ECM. DTC P0686 indicates an open, high resistance, or a short to ground in the main relay coil control circuit. If the fault detection circuit measures a low voltage condition, DTC P0686 will set.

This diagnostic procedure supports the following DTC

DTC P0686 Engine Controls Ignition Relay Control Circuit

  1. The battery voltage is between 9-16 volts.
  2. The ignition switch is turned ON.
  3. DTC P0686 runs continuously once the above conditions are met.
  1. The ECM detects a lower than expected voltage on the relay coil control circuit.
  2. The condition is present for more than 200 milliseconds.
  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. The main relay will remain powered up for 15 seconds after the ignition switch is turned OFF.
  2. This DTC diagnostic table assumes that the vehicle battery is fully charged. Refer to «Battery Inspection/Test»(/cadillac/srx/i-2003-2009/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.

The numbers below refer to the step numbers on the diagnostic table.

  1. 3: The engine will crank and run, with a short to ground on the main relay coil control circuit. This condition could result in a discharged battery.
  2. 5: The engine will crank but will not run, with a high resistance or an open on the main relay coil control circuit.
StepActionValuesYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views and Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the 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?Go to Step 3Go to Intermittent Conditions
3Attempt to start the engine. Does the engine start and run?Go to Step 6Go to Step 4
4Turn OFF the ignition. Remove the main relay from the underhood fuse block with the J 43244 Relay Puller Pliers. Refer to Relay Replacement (Within an Electrical Center) in Wiring Systems. NOTE: Refer to Test Probe Notice in Cautions and Notices. Probe the battery positive voltage terminal for the main relay coil at the underhood fuse block with a test lamp that is connected to a good ground. Refer to Troubleshooting with a Test Lamp in Wiring Systems. Does the test lamp illuminate?Go to Step 5Go to Step 10
5Turn ON the ignition, with the engine OFF. Probe the main relay coil control circuit terminal at the underhood fuse block with a test lamp that is connected to battery positive voltage. Does the test lamp illuminate?Go to Step 9Go to Step 17
6Turn OFF the ignition. Remove the main relay from the underhood fuse block with the J 43244 . Refer to Relay Replacement (Within an Electrical Center) in Wiring Systems. NOTE: Refer to Test Probe Notice in Cautions and Notices. Probe the main relay coil control circuit terminal at the underhood fuse block with a test lamp that is connected to battery positive voltage. Does the test lamp illuminate?Go to Step 7Go to Step 11
7Turn OFF the ignition. Disconnect the engine control module (ECM) electrical connector that contains the main relay coil control circuit. Refer to Engine Control Module (ECM) Replacement . NOTE: Refer to Test Probe Notice in Cautions and Notices. Probe the main relay coil control circuit terminal at the underhood fuse block with a test lamp that is connected to battery positive voltage. Does the test lamp illuminate?Go to Step 8Go to Step 13
8Turn OFF the ignition. Disconnect the negative battery cable at the battery. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical. Disconnect the underhood fuse block electrical connector that contains the main relay coil control circuit. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems. Connect the negative battery cable at the battery. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical. Probe the main relay coil control circuit terminal at the underhood fuse block electrical connector with a test lamp that is connected to battery positive voltage. Does the test lamp illuminate?Go to Step 14Go to Step 19
9Turn OFF the ignition. Disconnect the negative battery cable at the battery. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical. Disconnect the underhood fuse block electrical connector that contains the main relay coil control circuit. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems. Disconnect the ECM electrical connector that contains the main relay coil control circuit. Refer to Engine Control Module (ECM) Replacement . Measure the resistance of the main relay coil control circuit from the underhood fuse block electrical connector to the ECM electrical connector with a DMM. Refer to Troubleshooting with a Digital Multimeter in Wiring Systems. Does the resistance measure greater than the specified value?5 ohmsGo to Step 17Go to Step 11
10Probe the mounting stud for the battery positive cable at the underhood fuse block with a test lamp that is connected to a good ground. Does the test lamp illuminate?Go to Step 19Go to Step 15
11Measure the resistance from terminal #85 of the main relay to terminal #86 with a DMM. Refer to Troubleshooting with a Digital Multimeter in Wiring Systems. Does the resistance measure within the specified range?70-110 ohmsGo to Step 12Go to Step 18
12Test for an intermittent and for a poor connection at the main relay location of the underhood fuse block. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you find a condition?Go to Step 19Go to Step 13
13Test for shorted terminals and poor connections at the ECM electrical connectors. Refer to Testing for Intermittent Conditions and Poor Connections and Micro .64 Connectors in Wiring Systems. Did you find and correct the condition?Go to Step 21Go to Step 20
14Repair the short to ground in the main relay coil control circuit between the underhood fuse block electrical connector and the ECM electrical connector. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 21
15Test for an intermittent and for a poor connection in the battery positive cable between the underhood fuse block and the battery. Did you find and correct the condition?Go to Step 21Go to Step 16
16Replace the battery positive cable to the underhood fuse block. Refer to Battery Positive Cable Replacement (LY7) or Battery Positive Cable Replacement (LH2) in Engine Electrical. Did you complete the replacement?Go to Step 21
17Repair the high resistance or an open in the main relay coil control circuit between the underhood fuse block electrical connector and the ECM electrical connector. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 21
18Replace the main relay. Refer to Relay Replacement (Within an Electrical Center) in Wiring Systems. Did you complete the replacement?Go to Step 21
19Replace the underhood fuse block. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems. Did you complete the replacement?Go to Step 21
20Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 21
21Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the 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?Go to Step 3Go to Step 22
22Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK
NOTE
Refer to Test Probe Notice in Cautions and Notices.
NOTE
Refer to Test Probe Notice in Cautions and Notices.
NOTE
Refer to Test Probe Notice in Cautions and Notices.

DTC P0686

See also:
• Diagnostic System Check - Vehicle
• Diagnostic Trouble Code (DTC) List - Vehicle
• Road Test Caution
• Exhaust Leakage
• Restricted Exhaust
• Heated Oxygen Sensor (HO2S) Replacement Bank 1 Sensor 2
• Intermittent Conditions
• Special Tools
• Engine Control Module (ECM) Connector End Views
• Engine Controls Connector End Views
• Circuit Testing
• Wiring Repairs
• Testing for Intermittent Conditions and Poor Connections
• Connector Repairs
• Control Module References
• Evaporative Emission (EVAP) Canister Replacement
• Testing for Continuity
• Lifting and Jacking the Vehicle
• Testing for Short to Ground
• Probing Electrical Connectors
• Service Programming System (SPS)
• Accelerator Pedal Assembly Replacement
• Symptoms - Instrument Panel, Gages and Console
• Battery Inspection/Test
• Relay Replacement (Within an Electrical Center)
• Test Probe Notice
• Troubleshooting with a Test Lamp
• Troubleshooting with a Digital Multimeter
• DTC P0451

More articles — Engine Performance