Engine Control System Self-Diagnostics - 3.8l Buick Park Avenue II рестайлинг

MODEL IDENTIFICATION

Vehicle model is identified by fourth character of Vehicle Identification Number (VIN). VIN is stamped on metal pad on top of left end of instrument panel, near windshield. See MODEL IDENTIFICATION table.

MODEL IDENTIFICATION

INTRODUCTION

To properly diagnose and repair this vehicle, follow DIAGNOSTIC STARTING POINT - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM. If no Diagnostic Trouble Codes (DTC) are present and a no-start condition exists, proceed to appropriate NO-START DIAGNOSIS in BASIC DIAGNOSTIC PROCEDURES - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LE SABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no DTCs are present and a driveability condition exists, diagnose by symptom, see SYMPTOMS in TROUBLE SHOOTING - NO CODES - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.

ON-BOARD DIAGNOSTICS

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

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

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

Code Types

There are 4 types of DTC categories

1. Type "A" Emissions related. Illuminates MIL the first time DTC sets.
2. Type "B" Emissions related. Illuminates MIL if fault is active for 2 consecutive driving cycles.
3. Type "C" Non-emissions related. Does not illuminate MIL, but will illuminate SERVICE light.
4. Type "D" Non-emissions related. Does not illuminate MIL or SERVICE light.

Freeze Frame/Failure Records

PCM stores one freeze frame record (failure record "0") for the first failed test that sets a DTC and illuminates MIL. Freeze frame will not be overwritten unless a misfire or fuel trim DTC is set. Failure records are stored when any DTC is set. Six additional failure records can be stored in PCM. Failure records will be stored for all types of codes, whether or not the MIL is illuminated. If more than 6 DTCs are set, oldest DTC is deleted as newest DTC is stored. Typical failure record data includes

1. Air/fuel ratio.
2. Airflow rate.
3. Fuel trim.
4. Engine speed.
5. Engine load.
6. Engine coolant temperature.
7. Vehicle speed.
8. Throttle position angle.
9. Manifold absolute pressure.
10. Injector base pulse width.
11. Loop status.

Monitors

1. Comprehensive Component Monitor Monitors PCM systems for opens, shorts, grounds and out-of-range sensors. Also monitors rationality of sensors. Rationality is whether the sensor value is consistent with the operating conditions of the other sensors.
2. Misfire Monitor Monitors engine misfire using crankshaft sensor to determine location and severity of misfire. A catalyst damaging misfire will flash the MIL, and a non-catalyst damaging misfire is a normal type "B" code.
3. Fuel Trim Monitor Monitors short and long term fuel trim for being at maximum lean or rich limit.
4. Oxygen Sensor Monitor Monitors all oxygen sensors for maximum voltage level, minimum voltage level and lean rich/rich lean switching rate.
5. Oxygen Sensor Heater Monitor Monitors oxygen sensor heater by watching sensor's time-to-activity after a cold start.
6. Catalyst Monitor Monitors catalyst efficiency by comparing activity rate of pre-catalyst oxygen sensor and post-catalyst oxygen sensor.
7. EGR Monitor Monitors operation and flow rate of EGR system.
8. EVAP Monitor Monitors EVAP system for large leaks, small leaks and purge flow.
9. Secondary Air Monitor Monitors secondary air operation.

INTERMITTENT CONDITIONS

Note. Intermittent is a DTC or symptom, with a condition that cannot be duplicated.

Preliminary

Perform the Diagnostic System Check - Engine Controls before starting. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS .

Harness or Connector Intermittents

Many intermittent open or shorted circuits come and go with harness or connector movement caused by the following type conditions

1. Vibration.
2. Engine torque.
3. Bumps or rough pavement.

Test for intermittents by performing the applicable procedure from the following list

1. Move related connectors and wiring while monitoring the appropriate scan tool data.
2. Move related connectors and wiring with the component commanded ON and OFF, with the scan tool. Observe the component operation.
3. With engine running, move related connectors and wiring while monitoring engine operation.

Verify whether the harness or connector movement affects any of the following systems

1. Data displayed.
2. Component or system operation.
3. Engine operation.

Repair the components as necessary.

Electrical Connections or Wiring

1. Intermittents are usually caused by one or more of the following conditions: Poor electrical connections. Terminal tension. Wiring problems.
2. Carefully inspect the suspected circuit for the following conditions: Poor mating of the connector halves. Terminals backed out or not fully seated in the connector body. Improperly formed or damaged terminals. Test for poor terminal tension. Poor terminal-to-wire connections including terminals crimped over insulation. This requires removing the terminal from the connector body. Corrosion or water intrusion. Pierced or damaged insulation can allow moisture to enter the wiring. The conductor can corrode inside the insulation, with little visible evidence. Look for swollen and stiff sections of wire in the suspect circuits. Wires that are broken inside the insulation. Pinched, cut, or rubbed through wiring in the harness. Wiring that is in contact with hot exhaust components.
3. Repair the condition as necessary.

Control Module Power & Grounds, & Component Power & Grounds

Poor power or ground connections can cause widely varying symptoms.

1. Test all control module power circuits. Many vehicles have multiple circuits supplying power to the control module. Other components in the system may have separate power circuits that may also need to be tested. Inspect connections at the module or component connectors, fuses, and any intermediate connections between the power source and the module or component. A test light or a Digital Volt-Ohmmeter (DVOM) may indicate that voltage is present, but neither tests the ability of a circuit to carry sufficient current. Ensure that the circuit can carry the current necessary to operate the component. See «POWER DISTRIBUTION»(ref-154366-S38191361362003080900000) in SYSTEM WIRING DIAGRAMS article in WIRING DIAGRAMS.
2. Test all control module ground and system ground circuits. The control module may have multiple ground circuits. Other components in the system may have separate grounds that may also need to be tested. Inspect grounds for clean and tight connections at the grounding point. Inspect the connections at the component and in splice packs, where applicable. Ensure that the circuit can carry the current necessary to operate the component. See «WIRING DIAGRAMS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__wiring-diagrams) .

Temperature Sensitivity

1. An intermittent condition may occur when a component or connection reaches normal operating temperature. The condition may occur only when the component or connection is cold, or only when the connection is hot.
2. The following data may help to diagnose this type of intermittent condition: Freeze Frame/Failure Records. Scan tool snapshot. Vehicle data recorder.
3. If the intermittent is related to heat, review the following data: High ambient temperatures. Underhood or engine generated heat. Circuit generated heat due to a poor connection, or high electrical load. Higher than normal load conditions, such as towing.
4. If the intermittent is related to cold, review the following data: Low ambient temperatures. In extremely low temperatures, ice may form in a connection or component. Test for water intrusion. The condition only occurs on a cold start. The condition is not present after the vehicle warms up.
5. Information from the customer may help to determine if the trouble follows a pattern that is temperature related.

Electromagnetic Interference & Electrical Noise

Some electrical components or circuits are sensitive to Electromagnetic Interference (EMI) or other types of electrical noise. Perform the following procedures

1. Inspect for a misrouted harness that is too close to a high voltage or high current device. This condition may induce electrical noise on a circuit that could interfere with normal circuit operation. Inspect for wires that are too close to the following devices: Secondary ignition components. Motors. The generator.
2. Determine whether the electrical system interference is caused by a malfunctioning relay, PCM driven solenoid or switch. These components may cause a sharp electrical surge. Normally, the problem will occur when the malfunctioning component is operating.
3. Determine whether non-factory or aftermarket add-on accessories are installed in the vehicle. These accessories may lead to an emission related OBD-II failure. Determine if any of the following non-factory or aftermarket add-on accessories is causing the intermittent: Lights. 2-way radios. Amplifiers. Electric motors. Remote starters. Alarm systems. Cell phones.
4. Test for an open diode across the A/C compressor clutch and for other open diodes. Some relays may contain a clamping diode.
5. Test for proper performance of the generator. See ON-VEHICLE TESTING in appropriate GENERATORS & REGULATORS article in ELECTRICAL.
6. If a DTC is determined to be intermittent, and the tests do not reveal a problem, see «VEHICLE DATA RECORDER»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__vehicle-data-recorder) .

Incorrect PCM Programming

1. There are only a few situations when reprogramming a PCM is appropriate, such as the following: A new service PCM is installed. A PCM from another vehicle is installed. Revised software or calibration files have been released for this vehicle.
2. Verify that the PCM contains the correct software or calibration. If incorrect programming is found, reprogram the PCM with the most current software or calibration. See «POWERTRAIN CONTROL MODULE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under PROGRAMMING.

Duplicating Failure Conditions

1. If none of the previous tests are successful, attempt to duplicate or capture the failure conditions.
2. Freeze Frame/Failure Records data, where applicable, contains the conditions that were present when the DTC set. Perform the following procedure: Review and record Freeze Frame/Failure Records data. Clear the DTCs using the scan tool. Turn the key to OFF and wait 15 seconds. Operate the vehicle under the same conditions that were noted in Freeze Frame/Failure Records data, as closely as possible. The vehicle must also be operating within the Conditions for Running DTC. Monitor DTC Status for the DTC being tested. The scan tool will indicate Ran, when the enabling conditions have been satisfied long enough for the DTC to run. The scan tool will also indicate whether the DTC passed or failed.
3. An alternate method is to drive the vehicle with the DVOM connected to a suspected circuit. An abnormal reading on the DVOM when the problem occurs, may help you locate the problem.

Scan Tool Snapshot

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

Vehicle Data Recorder

The Vehicle Data Recorder (J 42598) is connected to the Data Link Connector (DLC) and sent with the customer. The Vehicle Data Recorder captures data for later retrieval and analysis by the technician. Refer to the vehicle data recorder user instructions for more information.

DIAGNOSTIC STARTING POINT - ENGINE CONTROLS

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

1. Ensure all engine systems not related to computer system are operating properly. DO NOT proceed with testing unless all other problems have been repaired. Diagnostic system check must be performed before using specific DTC testing procedure. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) .
2. If no DTCs are present and a driveability problem exists, refer to «SYMPTOMS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-troubleshooting-no-codes-38l__symptoms) in TROUBLE SHOOTING - NO CODES - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. Doing so will help identify proper system or component to check in «SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l) article.
3. After necessary repairs are made, clear DTCs, verify vehicle will enter "closed loop" operation and ensure DTC does not reset.

Description

The Diagnostic System Check is an organized approach to identifying a condition that is created by a malfunction in the powertrain control system. The Diagnostic System Check must be the starting point for any driveability concern. The Diagnostic System Check directs the service technician to the next logical step in order to diagnose the concern. Understanding and correctly using the diagnostic table reduces diagnostic time, and prevents the replacement of good parts.

Test Description

The numbers below refer to the step numbers in the diagnostic procedures.

1. 2 Lack of communication may be caused by a partial or a total malfunction of the Class 2 serial data circuit. The specified procedure determines the particular condition.
2. 5 This step stores the Powertrain Control Module (PCM) Diagnostic Trouble Code (DTC) information into the scan tool's memory. After you complete the diagnostic procedure, review the captured information in order to catch the next DTC if the control module stores multiple DTCs. Review the Freeze Frame data and the Failure Records data. Use this information in order to determine how frequently and how recently the DTC set. This information may help diagnose an intermittent condition. Information about the operating conditions at the time that the DTC set may also help diagnose an intermittent condition. Capturing the stored information saves the data that the PCM loses during the following conditions: When a diagnostic procedures instructs you to clear the DTCs. When a diagnostic procedure instructs you to disconnect the PCM connectors. When a diagnostic procedure instructs you to replace the PCM. See «REMOVAL & INSTALLATION - BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL»(/buick/park-avenue/ii-2002-2005/remont/removal-installation/#engine-controls-removal-installation) article.
3. 6 The presence of DTCs which begin with "U", indicate that some other module is not communicating. Following the specified procedure will gather all the available information before you perform the tests.
4. 8 If there are other modules with DTCs set, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) . The DTC list directs you to the appropriate diagnostic procedure. If the control module stores multiple powertrain DTCs, diagnose the DTCs in the following order: Component level DTCs, such as sensor DTCs, solenoid DTCs, and relay DTCs. Diagnose the multiple DTCs within this category in numerical order. Begin with the lowest numbered DTC, unless the diagnostic procedure directs you otherwise. System level DTCs, for example, misfire DTCs, fuel trim DTCs, and catalyst DTCs.
5. 10 This step is for areas that have inspection and maintenance testing procedures for emissions testing. Use this step if the testing facility found one or more I/M system status that did not set.

Diagnostic Procedures

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

1. Install a scan tool. Does the scan tool turn ON? If yes, go to next step. If no, see SCAN TOOL DOES NOT POWER UP in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
2. Turn ON the ignition, with the engine OFF. Attempt to establish communication with the listed control modules. If you are using a Tech 2, obtain the information using the Class 2 Message Monitor feature: PCM. Vehicle Theft Deterrent (VTD). Instrument Panel (IP) cluster. Electronic Brake Control Module (EBCM). HVAC Does the scan tool communicate with all the listed control modules? If yes, go to next step. If no, see SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
3. Attempt to start the engine. Does the engine start and idle? If yes, go to next step. If no, see «NO-START DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__no-start-diagnosis) in BASIC DIAGNOSTIC PROCEDURES - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LE SABRE, MONTE CARLO, PARK AVENUE & REGAL.
4. Select the DTC display function for the following control modules: PCM, VTD, IP Cluster and EBCM. Does the scan tool display any DTCs? If yes, go to next step. If no, go to step 9 .
5. With a scan tool, select Captured Info in order to store the powertrain DTC information. When complete, go to next step.
6. Does the scan tool display DTCs which begin with a "U"? If yes, see appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If no, go to next step.
7. Does the scan tool display DTC P0601 or P0602? If yes, see «DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683 & P2610: PCM INTERNAL MICROPROCESSOR INTEGRITY»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__dtc-p0601-p0607-p1600-p1621-p1627-p1680) under DIAGNOSTIC TESTS. If no, go to next step.
8. Does the scan tool display DTC P0560? If yes, see appropriate GENERATORS & REGULATORS article in ELECTRICAL. If no, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) .
9. Is the customer's concern with the automatic transmission? If yes, see appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS. If no, go to next step.
10. Is the customer's concern with Inspection and Maintenance (I/M) testing? If yes, see «INSPECTION/MAINTENANCE SYSTEM CHECK»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under INSPECTION/MAINTENANCE PROCEDURES.
11. Review the following symptoms. Hard start, surges/chuggles, lack of power, sluggishness, sponginess, detonation/spark knock, hesitation, sag, stumble, cuts out, misses, poor fuel economy, poor fuel fill quality, rough, unstable, or incorrect idle and stalling, dieseling, run-on and backfire. See «SYMPTOMS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-troubleshooting-no-codes-38l__symptoms) TROUBLE SHOOTING - NO CODES - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. Did you find and correct the condition? If yes, system is okay. If no, see «INTERMITTENT CONDITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__intermittent-conditions) .

RETRIEVING DIAGNOSTIC TROUBLE CODES

DTCs are retrieved by performing Diagnostic System Check - Engine Controls with Tech 2 scan tool, or other OBD-II compatible scan tool connected to OBD-II 16-pin Data Link Connector (DLC). See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS . See CONNECTOR IDENTIFICATION . DLC is located below left side of dash.

CLEARING DIAGNOSTIC TROUBLE CODES

There are 3 methods to clear DTCs.

Scan Tool

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

Disconnect Battery

Note. On many OBD-II systems, PCM will retain memory for an extended period of time with battery disconnected. Memory may be retained for several days.

Disconnecting PCM power or battery ground will clear all PCM memory including DTCs, freeze frame, failure records, adaptive learning and system monitors.

Warm-up Cycles

If fault that caused DTC to set is repaired, PCM will begin to count warm-up cycles. After 40 consecutive warm-up cycles with no further faults, PCM will automatically clear DTC from memory.

SCAN TOOL USAGE

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

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

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

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

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

Scan Tool Display

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

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

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

POWERTRAIN CONTROL MODULE LOCATION

Powertrain control module is located inside air cleaner box. See COMPONENT LOCATIONS .

CKP SYSTEM VARIATION LEARN PROCEDURE

1. Install a scan tool.
2. With a scan tool, monitor the Powertrain Control Module (PCM) for DTCs. If other DTCs are set, except DTC P1336, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) .
3. With a scan tool, select the Crankshaft Position (CKP) variation learn procedure.
4. Observe the fuel cut-off for the engine that you are performing the learn procedure on.
5. The scan tool instructs you to perform the following: Block drive wheels. Apply the vehicle's parking brake. Cycle the ignition from off to on. Apply and hold brake pedal. Start and idle the engine. Turn off the A/C. Place transmission in Park (A/T) or Neutral (M/T). The scan tool monitors certain component signals to determine if all the conditions are met to continue with the procedure. The scan tool only displays the condition that inhibits the procedure. The scan tool monitors the following components: CKP sensors activity. If there is a CKP sensor condition, refer to the applicable DTC that set. Camshaft Position (CMP) sensor activity. If there is a CMP sensor condition, refer to the applicable DTC that set. Engine Coolant Temperature (ECT). If the ECT is not warm enough, idle the engine until the ECT reaches the correct temperature.
6. With the scan tool, enable the CKP system variation learn procedure.
7. Slowly increase the engine speed to the RPM that you observed.
8. Immediately release the throttle when fuel cut-off is reached.
9. The scan tool displays Learn Status: Learned this ignition. If the scan tool does not display this message and no additional DTCs set, repair engine mechanical problem. See appropriate article in ENGINES. If a DTC set, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) .
10. Turn off the ignition for 30 seconds after the learn procedure is completed successfully.

Bonneville, Impala & Monte Carlo

Using The Radio

1. Turn the ignition to ACC or ON, with the radio OFF.
2. Press and hold the TUNE DISP button on the radio for at least 5 seconds until SETTINGS is displayed.
3. Press the SEEK PTYPE or the SEEK PSCAN up or down arrow to scroll through the main menu.
4. Scroll until OIL LIFE appears on the display.
5. Press the 1 PREV or 2 NEXT button to enter the sub menu. RESET will be displayed.
6. Press the TUNE DISP button to reset. A chime will be heard to verify the new setting and DONE will be displayed for one second.
7. Once the message has been reset, scroll until EXIT appears on the display.
8. Press the TUNE DISP button to exit programming. A chime will be hear to verify the exit.

Using The Accelerator Pedal

1. Turn the ignition ON, with the engine OFF.
2. Fully press and release the accelerator pedal 3 times within 5 seconds. If the CHANGE ENGINE OIL message flashes, the system reset. However, if it stays on, it did not reset. Repeat the procedure.

Grand Prix

Without Trip Computer

1. Turn the ignition to RUN, with the engine OFF.
2. Fully press and release the accelerator pedal 3 times within 5 seconds.
3. If the CHANGE OIL SOON light flashes, the system is resetting.
4. Turn the key to OFF after the light has finished flashing, then start engine.
5. If the CHANGE OIL SOON light comes back on, the engine oil life system did not reset. Repeat the procedure.

With Trip Computer

1. Press the MODE button until the light appears next to OIL LIFE.
2. Press and hold the RESET button for 3 seconds. The oil life percentage should change to 10 percent.

LeSabre, Park Avenue & Regal

1. Display OIL LIFE INDEX on the DIC.
2. Press and hold the RESET button on the DIC for more than 5 seconds. The oil life will change to 100 percent.

Regal

Without Driver Information Center (DIC)

1. Turn ignition on, with engine off.
2. Fully press and release the accelerator pedal slowly 3 times within 5 seconds.
3. If the CHANGE OIL SOON light flashes, the system is resetting.
4. Turn ignition off.
5. Start vehicle.
6. The oil life will change to 100 percent.
7. If the CHANGE OIL SOON light comes back on, the system has not reset. Repeat reset procedure.

With Driver Information Center (DIC)

1. Put the oil life display on, with engine off.
2. Press the DIC RESET button for 5 seconds.

Remote Programming

The Remote SPS method is a 3 step process that involves the following procedures

1. Connecting the Tech 2® to the vehicle and obtaining the information from the module.
2. Connecting the Tech 2® to the terminal and downloading a new calibration file from the terminal into the Tech 2® memory.
3. Reconnecting the Tech 2® to the vehicle and uploading the new calibration file into the module.

Performing Remote Procedure

1. Connect the Tech 2® to the vehicle and obtain the module information using the following: NOTE: Ensure the control module is installed in the vehicle and the battery is fully charged before programming. Connect the Tech 2® to the vehicle DLC, with engine and Tech 2® OFF. Turn ON the Tech 2®. Press ENTER at the title screen. Turn ignition on, with engine off. Select SERVICE PROGRAMMING at the Main Menu. NOTE: Select REQUEST INFO AGAIN if a Vehicle Identification Number (VIN) was previously stored in the Tech 2®. Select REQUEST INFO. Enter the vehicle description by following the on-screen instructions. Turn OFF all accessories and select CONTINUE. NOTE: Select NO and write down the VIN if the VIN is incorrect. Verify that the correct VIN is entered on the Tech 2® and select YES.
2. Turn OFF the Tech 2®.
3. Disconnect the Tech 2® from the vehicle.
4. Turn OFF the ignition.
5. Transfer the data from the terminal to the Tech 2® using the following procedure: Connect the Tech 2® to the terminal. NOTE: The TIS supports service programming with the Tech 2® scan tool only. Launch the TIS application at the terminal. Select the SERVICE PROGRAMMING SYSTEM at the Main Screen. Highlight the following information on the Select Diagnostic Tool and Programming Process Screen: Select Diagnostic Tool, select Tech 2®. Select Programming Process, identify whether an existing module is being reprogrammed or a module is being replaced with a new one. Select ECU, select vehicle. Select Next. Verify the connections and select Next. NOTE: You may receive a message stating that the control module could be a service control module if you selected NO to the VIN being correct. Click OK. Verify the VIN and select Next. Select the appropriate controller for the vehicle being serviced. NOTE: When selecting the Vehicle Configuration Index (VCI) programming type, a valid VCI number for the vehicle must be entered. This number may be obtained from the Techline® Customer Support. Select the type of programming to be performed from the following categories: Normal Used for updating an existing calibration or programming a new controller. Vehicle Configuration Index (VCI) Used for updating an existing controller or programming a new controller for newer vehicles whose VINs are not yet in the database. Reconfigure Used to reconfigure a vehicle for changes in tire size and axle ratios. Select Next. NOTE: Refer to service bulletins before service programming is performed if the bulletins are listed along with calibration files. Select the appropriate calibration file for the vehicle being serviced. Select Next. NOTE: Select Cancel if you receive a message stating that the calibration selected is already the current calibration in the control module and reprogramming with the same download is not allowed. Verify your selection on the Summary screen. Select Next.
6. Perform the «CKP SYSTEM VARIATION LEARN PROCEDURE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__ckp-system-variation-learn-procedure) using the Special Functions feature, if applicable.
7. Close the application and return to the TIS application selection screen after the download is complete.
8. Turn OFF the Tech 2®.
9. Disconnect the Tech 2® from the terminal.
10. Transfer the data from the Tech 2® to the control module using the following procedure: Connect the Tech 2® to the vehicle DLC, with the engine and the Tech 2® OFF. Turn ON the Tech 2®. Press ENTER at the Title screen. Turn ignition on, with engine off. Select Service Programming System. Select the Program ECU function on the Tech 2®. Verify the VIN and calibration numbers, select Continue. Follow the on-screen instructions and select Continue. Select continue and exit the program after the Tech 2® displays Programming Was Successful.
11. Turn OFF the ignition.
12. Turn OFF the Tech 2®.
13. Disconnect the Tech 2® from the vehicle.

Some vehicles will require that the Idle Learn, TP Learn, Theft Relearn, or Crankshaft Variation Learn procedures be performed after programming. Consult the appropriate service information for these procedures. Verify the control module programming was successful using the following procedure

1. Turn OFF the ignition for 30 seconds.
2. Start engine.

Off-Board Remote Programming Procedure

Note. Ensure the Tech 2® and the terminal are both equipped with the latest software before performing SPS.

The Off-Board Programming Adapter Kit (J 41207) is required when a module must be programmed without having the vehicle present. The adapter allows the module to be turned ON and communicate with the scan tool.

Performing Off Board Remote Procedure

1. Obtain the Vehicle Identification Number (VIN) of the vehicle for which the module is being programmed.
2. Launch the TIS application at the terminal.
3. Select the Service Programming System.
4. Highlight the following information on the Select Diagnostic Tool and Programming Process screen: Select Diagnostic Tool, select Tech 2®. Select Programming Process, identify whether an existing module is being reprogrammed or replaced with a new one. Select ECU location, select Off-Board Programming Adapter.
5. Select, Next.
6. Follow the directions on the Preparing For Communication screen for connecting the following components: The control module. The Off-Board Programming Request Information function on the Tech 2®. The Tech 2®.
7. Select the Service Programming Request Information function on the Tech 2®.
8. Follow the Tech 2® instructions to obtain the module data and security information.
9. After the Tech 2® has received the data from the module, exit the Request Info mode.
10. Disconnect the Tech 2® from the OBPA.
11. Turn Off the Tech 2®.
12. Connect the Tech 2® to the terminal.
13. Turn ON the Tech 2®.
14. Select Next at the terminal after the Tech 2® start-up screen appears.
15. Enter the VIN of the vehicle that will be receiving the control module.
16. Select Next.
17. Select the type of programming to be performed from the following categories: Normal Used for updating an existing calibration or programming a new controller. Vehicle Configuration Index (VCI) Used for updating an existing controller or programming a new controller for newer vehicles whose VINs are not yet in the database. Reconfigure Used to reconfigure a vehicle for changes in tire size and axle ratios.
18. Select Next.
19. Select a calibration on the Calibration Selection screen, if necessary.
20. Ensure all the desired folder tabs have a Green check mark.
21. Select Next.
22. Verify the current and the selected calibration of the control module on the Summary screen.
23. Select Next.
24. Select OK.
25. On model year 1996 and newer controllers, a Crankshaft Position (CKP) relearn procedure box may appear. Select OK.
26. Follow the on-screen instructions, if any, when the Program Controller/Programming Complete screen appears.
27. Select Close.
28. Turn OFF the Tech 2®.
29. Disconnect the Tech 2® from the terminal.
30. Connect the Tech 2® to the OBPA.
31. Turn ON the Tech 2®.
32. Select ENTER at the Title screen.
33. Select the Service Programming System at the Main Menu.
34. Select the Program ECU function.
35. Select Continue.
36. Follow the on-screen instructions.
37. Select Continue.
38. Select Exit when the Programming is complete.
39. Turn OFF the OBPA.
40. Turn OFF the Tech 2®.
41. Disconnect the OBPA from the Tech 2® and the control module.

Pass-Thru Procedure

Note. The TIS supports service programming with the Tech 2® scan tool only.

Pass-Thru programming allows the scan tool to remain connected to the terminals and to the vehicle throughout the programming process. The vehicle must be in close proximity to the terminal while using Pass-Thru.

1. Launch the TIS application at the terminal.
2. Select the Service Programming System.
3. Highlight the following information on the Select Diagnostic Tool Programming Process screen: Select Diagnostic Tool, select Pass-Thru. Select Programming Process, identify whether an existing module is being reprogrammed or a module is being replaced with a new one. Select ECU location, select vehicle.
4. Select Next.
5. Complete all terminal-directed data on the Preparing for Communication/Determine Vehicle screen until Next is highlighted.
6. Select Next.
7. Follow the instructions on the Preparing for Communication screen.
8. Select Next.
9. Verify the VIN on the Validate Vehicle Identification Number screen.
10. Select Next.
11. If an option screen appears, verify the vehicle configuration and/or RPO information.
12. Select Next.
13. Highlight the appropriate control module and programming type on the Supported Controllers screen.
14. Select Next.
15. Select the proper calibrations on the Calibration Selection screen.
16. Ensure all the folder tabs have a Green check mark.
17. Select Next.
18. Verify the current calibrations with the selected calibrations.
19. Select Next.
20. The Transfer Data screen will appear until the process bar reaches 100 percent. This may take up to 30 minutes.
21. Complete all of the terminal-directed data on the Programming Complete screen.
22. Turn OFF the Tech 2®.
23. Disconnect the Tech 2® from the vehicle.

Off-Board Pass-Thru Procedure

Note. Ensure the Tech 2® and the terminal are both equipped with the latest software before performing SPS.

The Off-Board Programming Adapter Kit (J 41207-C) is required when a module must be programmed without having the vehicle present. The adapter allows the module to be turned ON and communicate with the Tech 2®.

Performing Off-Board Pass-Thru Procedure

1. Launch the TIS application in the terminal.
2. Select the Service Programming System.
3. Highlight the following information on the Select Diagnostic Tool and Programming Process Screen: Select Diagnostic Tool Select Pass-Thru. Select Programming Process Identify whether an existing module is being reprogrammed, or a module is being replaced with a new one. Select ECU Location Select Off-Board Programming Adapter.
4. Select Next.
5. Complete all terminal-directed data at the Preparing for Communication/Determine Vehicle screen until Next is highlighted.
6. Select Next.
7. Follow the on-screen instructions for connecting the following components: The control module. The Off-Board Programming Adapter (OBPA), refer to the TIS Users Guide for a listing of OBPA. The Tech 2®.
8. Select Next.
9. Pass-Thru displays the VIN stored in the control module. If a new control module is being programmed, enter the correct VIN of the vehicle.
10. Select Next.
11. Select the appropriate options if the Options screen appears.
12. Select Next.
13. Select the type of programming to be performed from the following categories: Normal Used for updating an existing calibration or programming a new controller. Vehicle Configuration Index (VCI) Used for updating an existing controller or programming a new controller for newer vehicles whose VINs are not yet in the database. Reconfigure Used to reconfigure a vehicle for changes in tire size and axle ratios.
14. Select Next.
15. Select a calibration selection on the Calibration Selection screen, if necessary.
16. Ensure all the desired calibration folder tabs have a Green check mark.
17. Select Next.
18. Verify the current and selected calibration of the control module on the Summary screen.
19. Select Next.
20. Select OK.
21. Select OK.
22. When programming is complete, a Program Controller/Programming Complete screen appears. Follow the on-screen instructions, if any.
23. Select Close.
24. Turn OFF the OBPA.
25. Turn OFF the scan tool.
26. Disconnect the OBPA from the Tech 2 and the control module.

Note. The Body Control Module (BCM) must be programmed with the proper RPO configurations before performing learn procedures. See appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If replacing the BCM with a GM Service Parts Operations (SPO) replacement part, the module will learn Passlock® sensor data code immediately. The existing PCM however, must learn the new fuel continue password when the BCM is replaced. If replacing a PCM with a GM Service Parts Operations (SPO) replacement part, after programming, these modules will learn the incoming fuel continue password immediately upon receipt of a password message. Once a password message is received, and a password is learned, a learn procedure must be performed to change this password again. A PCM which has been previously installed in another vehicle will have learned the other vehicle's fuel continue password and will require a learn procedure after programming to learn the current vehicle's password.

10-Minute Learn Procedure

1. Connect the Tech 2 to the vehicle.
2. Select REQUEST INFORMATION under SERVICE PROGRAMMING.
3. Disconnect the Tech 2 from the vehicle and connect it to a Techline® terminal.
4. On the Techline® terminal, select THEFT MODULE RE-LEARN under SERVICE PROGRAMMING.
5. Disconnect the Tech 2 from the Techline® terminal and connect it to the vehicle.
6. Turn ignition on, with engine off.
7. Select VTD RE-LEARN under SERVICE PROGRAMMING.
8. Attempt to start the engine, then release the key to on (vehicle will not start).
9. Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn off (the vehicle is now ready to relearn the Passlock® Sensor Data Code and/or password on the next ignition switch transition from off to crank).
10. Turn off the ignition, and wait 5 seconds.
11. Start engine (the vehicle has now learned the password).
12. With scan tool, clear any DTCs.

30-Minute Learn Procedure

1. Turn ignition on, with engine off.
2. Attempt to start the engine, then release the key to on (vehicle will not start).
3. Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn off.
4. Turn off the ignition, and wait 5 seconds.
5. Repeat procedure 2 more times for a total of 3 cycles/30 minutes (the vehicle is now ready to relearn the Passlock® Sensor Data Code and/or passwords on the next ignition switch transition from off to crank).
6. Start the engine (the vehicle has now learned the Passlock® Sensor Data Code and/or password).
7. With a scan tool, clear any DTCs if needed (history DTCs will self clear after 100 ignition cycles).

Note. When replacing a theft deterrent control module with a GM SPO replacement part, the theft deterrent control module will learn the keys immediately. The PCM uses a common fuel enable signal which is received from the theft deterrent control module. Therefore, the 10-minute relearn procedure or the 30-minute relearn procedure is not required.

Set Up A New Theft Deterrent Control Module

1. With a master Passkey III key, start engine. The theft deterrent control module has now learned the key transponder information.
2. With a second master PK3 key, start engine. The theft deterrent control module has now learned the second master PK3 transponder information.
3. When additional keys are required to be learned, see ADDING KEYS in appropriate ANTI-THEFT SYSTEMS article under ACCESSORIES & EQUIPMENT.
4. Connect scan tool to vehicle.
5. Turn ignition on, with engine off.
6. With a scan tool, select Setup New VTD Module in the Vehicle Theft Deterrent, Special Functions data list.
7. Follow the scan tool on-screen instructions.

Note. When replacing a theft deterrent control module with a GM Service Parts Operation (SPO) Replacement Part, set up the control module prior to the 10-minute relearn procedure or the 30-minute relearn procedure has been performed. When replacing a theft deterrent control module with a GM SPO Replacement Part, the theft deterrent control module will learn the keys immediately. The Powertrain Control Module (PCM) uses a common fuel enable signal which is received from the theft deterrent control module. Therefore, the 10-minute relearn procedure or the 30-minute relearn procedure is not required. When replacing PCM with a GM SPO Replacement Part, the new PCM will learn the incoming fuel enable signal immediately upon receipt. When performing either relearn procedure, all previously learned keys will be erased from the theft deterrent control module's memory. Use only a master PK3 key when performing the first relearn procedure. If you use a valet key first, the theft deterrent control module will now allow additional keys to be learned.

10-Minute Relearn Procedure

1. Connect a scan tool to the vehicle.
2. Turn ON the ignition, with the engine OFF.
3. Insure that all power consuming devices are turned OFF on the vehicle.
4. With a scan tool, select Request Info. under Service Programming System and follow the scan tool on-screen instructions.
5. Disconnect the scan tool from the vehicle and connect the scan tool to a Techline Terminal with the current Service Programming System (SPS) software.
6. On the Techline Terminal, select Service Programming System and follow the Techline Terminal on-screen instructions.
7. Disconnect the scan tool from the Techline Terminal and re-connect the scan tool to the vehicle.
8. With a master passkey III key, turn ignition on, with engine off.
9. With a scan tool, select Program ECU under Service Programming System.
10. At this point the scan tool must remain connected for the duration of the 10-minute relearn procedure.
11. Observe the scan tool, after approximately 10 minutes the scan tool will display "Programming Successful, Turn OFF Ignition". The vehicle is now ready to relearn the key information on the next ignition switch transition from OFF to CRANK.
12. Turn OFF the ignition and wait 5 seconds.
13. With a master PK3 key, start engine. The theft deterrent control module has now learned the key transponder information.
14. Turn OFF the ignition and wait 15 seconds minimum.
15. With a second master passkey III key, start engine. The theft deterrent control module has now learned the second master Passkey III key transponder information
16. When additional keys are required to be learned, see ADDING KEYS in appropriate ANTI-THEFT SYSTEMS article under ACCESSORIES & EQUIPMENT.
17. With a scan tool, clear any DTCs.

Use this procedure is replacing the Passkey III (PK3) keys.

30-Minute Relearn Procedure

1. With a master passkey III key, turn ON the ignition, with the engine OFF.
2. Observe the Security telltale, after approximately 10 minutes the telltale will turn off.
3. Turn OFF the ignition, and wait 5 seconds.
4. Repeat steps 1-3 two more times for a total of 3 cycles or 30 minutes.
5. With a master passkey III key, start engine. The vehicle has now learned the key transponder information and the PCM has now learned the fuel continue password.
6. When additional keys are required to be learned, see ADDING KEYS in appropriate ANTI-THEFT SYSTEMS article under ACCESSORIES & EQUIPMENT.
7. With a scan tool, clear any DTCs.

LeSabre & Park Avenue

Note. When replacing a theft deterrent control module with an GM Service Parts Operation (SPO) Replacement Part, set up the control module prior to the 10-minute relearn procedure or the 30-minute relearn procedure.

Set Up A New Theft Deterrent Control Module

1. Connect a scan tool to the vehicle.
2. Turn ON the ignition, with the engine OFF.
3. With a scan tool, select Setup New VTD Module in the Vehicle Theft Deterrent, Special Functions data list.
4. Follow the scan tool on-screen instructions.

Note. When replacing a theft deterrent control module with an GM SPO Replacement Part, the module will learn the keys immediately. The existing Powertrain Control Module (PCM) must learn the new fuel continue password when you replace the theft deterrent control module. When replacing a PCM with a GM SPO Replacement Part, the new PCM will learn the incoming fuel continue password immediately after programming and upon receipt of a password message. Once a password message is received and a password is learned, perform the learn procedure to change this password again. A PCM which had been installed in another vehicle will have learned the fuel continue password of the other vehicle's theft deterrent control module. Perform either the 10-minute relearn procedure or the 30-minute relearn procedure after programming to learn the fuel continue password of the current vehicle's theft deterrent control modules. When performing either relearn procedure, all previously learned keys will be erased from the theft deterrent control module's memory. Additional keys may be learned immediately after the first relearn procedure by inserting the additional key and turning the ignition to RUN within 10 seconds of removing the previously learned key. Use only a master key when performing the first relearn procedure. If you use a valet key first, the theft deterrent control module will not allow additional keys to be learned.

10-Minute Relearn Procedure

1. Connect a scan tool to the vehicle.
2. Turn ignition on, with engine off.
3. Insure that all power consuming devices are turned off on the vehicle.
4. With a scan tool, select Request Info. under Service Programming System and follow the scan tool on-screen instructions.
5. Disconnect the scan tool from the vehicle and connect the scan tool to a Techline® Terminal with the current Service Programming System (SPS) software.
6. On the Techline® Terminal, select Service Programming System and follow the Techline® Terminal on-screen instructions.
7. Disconnect the scan tool from the Techline® Terminal and re-connect the scan tool to the vehicle.
8. With a master Passkey® III key, turn ignition on, with engine off.
9. With a scan tool, select Program ECU under Service Programming System.
10. At this point the scan tool must remain connected for the duration of the 10-minute relearn procedure.
11. Observe the scan tool, after approximately 10 minutes the scan tool will display "Programming Successful, Turn off Ignition". The vehicle is now ready to relearn the key information and/or the passwords on the next ignition switch transition from off to on.
12. Turn off the ignition and wait 5 seconds.
13. With a master Passkey® III key, start engine. The theft deterrent control module has now learned the key transponder information and the PCM has now learned the fuel continue password.
14. Turn off the ignition and wait 15 seconds minimum.
15. With a second master Passkey® III key, start engine. The theft deterrent control module has now learned the second master Passkey® III key transponder information.
16. With a scan tool, clear any DTCs.

Note. Use this procedure after replacement of Passkey® III keys, theft deterrent control module or PCM.

30-Minute Relearn Procedure

1. With a master Passkey® III key (Black), turn on the ignition, with the engine off.
2. Observe the Security telltale, after approximately 10 minutes the telltale will turn off.
3. Turn off the ignition, and wait 5 seconds.
4. Repeat procedure 2 more times for a total of 3 cycles or 30 minutes.
5. With a master Passkey® III key, start engine. The vehicle has now learned the key transponder information and the PCM has now learned the fuel continue password.
6. With a scan tool, clear any DTCs.

Note. The Body Control Module (BCM) must be programmed with the proper RPO configurations before performing learn procedures. See appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If replacing the BCM with a GM Service Parts Operations (SPO) replacement part, the module will learn Passlock® sensor data code immediately. The existing PCM however, must learn the new fuel continue password when the BCM is replaced. If replacing a PCM with a GM Service Parts Operations (SPO) replacement part, after programming, these modules will learn the incoming fuel continue password immediately upon receipt of a password message. Once a password message is received, and a password is learned, a learn procedure must be performed to change this password again. A PCM which has been previously installed in another vehicle will have learned the other vehicle's fuel continue password and will require a learn procedure after programming to learn the current vehicle's password.

10-Minute Learn Procedure

1. Connect the Tech 2® to the vehicle.
2. Select "REQUEST INFORMATION" under "SERVICE PROGRAMMING".
3. Disconnect the Tech 2® from the vehicle and connect it to a Techline® terminal.
4. On the Techline® terminal, select "THEFT MODULE RE-LEARN" under "SERVICE PROGRAMMING".
5. Disconnect the Tech 2® from the Techline® terminal and connect it to the vehicle.
6. Turn ON the ignition, with the engine OFF.
7. Select "VTD RE-LEARN" under "SERVICE PROGRAMMING".
8. Attempt to start the engine, then release the key to ON (vehicle will not start).
9. Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF (the vehicle is now ready to relearn the password on the next ignition switch transition from OFF to CRANK).
10. Turn OFF the ignition, and wait 5 seconds.
11. Start the engine (the vehicle has now learned the password).
12. With the Tech 2® (scan tool), clear any DTCs.

30-Minute Learn Procedure

1. Turn ON the ignition, with the engine OFF.
2. Attempt to start the engine, then release the key to ON (vehicle will not start).
3. Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF.
4. Turn OFF the ignition, and wait 5 seconds.
5. Repeat steps 1 - 4 2 more times for a total of 3 cycles/30 minutes (the vehicle is now ready to relearn the password on the next ignition switch transition from OFF to CRANK).
6. Start the engine (vehicle has now learned the password).
7. With a scan tool, clear any DTCs if needed (history DTCs will self clear after 100 ignition cycles).

DRIVE CYCLES

See INSPECTION/MAINTENANCE SYSTEM CHECK .

Several states require that a vehicle pass On-Board Diagnostic (OBD) system tests and the I/M emission inspection in order to renew license plates. This is accomplished by viewing the I/M system status display on a scan tool. Using a scan tool, the technician can observe the I/M system status in order to verify that the vehicle meets the criteria that complies with the local area requirements.

Conditions for Updating I/M System Status

Each system requires at least one, and sometimes several, diagnostic tests. The results of these tests are reported by a Diagnostic Trouble Code (DTC). A system monitor is complete when either all of the DTCs comprising the monitor have run and passed, or any one of the DTCs comprising the monitor have illuminated the MIL. Once all of the tests are completed, the I/M System Status display will indicate YES in the COMPLETED column. For example, when the HO2S Heater Test indicates YES, all of the oxygen sensor heaters have been diagnosed. If the vehicle has four heated oxygen sensors, all four heater circuits have been diagnosed. The I/M System Status will indicate NO under the Completed column when any of the required tests for that system have not run. The following is a list of conditions that would set the I/M system status indicator to NO

1. Vehicle is new from the factory and has not yet been driven through the necessary drive conditions to complete the tests.
2. Battery has been disconnected or discharged below operating voltage.
3. Control module power or ground has been interrupted.
4. Control module has been reprogrammed.
5. The control module DTCs have been cleared as part of a service procedure.

Monitored Emission Control Systems

The OBD-II System monitors all emission control systems that are on-board. Not all vehicles have a full complement of emission control systems. For example, a vehicle may not be equipped with Secondary Air Injection (AIR) or Exhaust Gas Recirculation (EGR). The OBD-II regulations require monitoring of the following

1. Air conditioning system.
2. Catalytic converter efficiency.
3. Comprehensive component monitoring. Emission related inputs and outputs.
4. Evaporative (EVAP) emissions system.
5. Exhaust Gas Recirculation (EGR) system.
6. Fuel delivery system.
7. Heated catalyst monitoring.
8. Misfire monitoring.
9. Oxygen Sensor (O2S) system.
10. Heated Oxygen Sensor (HO2S) heater system.
11. Secondary Air Injection (AIR) system.

For the specific DTCs required for each system, see INSPECTION/MAINTENANCE SYSTEM DTCS table. Systems such as fuel delivery, misfire, and comprehensive components may not be listed in a system status list. These tests run continuously on some vehicles and may not require an indicator.

Diagnostic Aids

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

The numbers below refer to the step numbers in the procedure.

1. 1 Any DTCs set, even those that are not listed in the Inspection/Maintenance System DTC Table, may prevent the required DTCs from running. If there is any question as to whether a set DTC is disabling the required I/M diagnostic, review the Conditions for Running in the diagnostic procedures for the DTC required by the I/M diagnostic. A list of disabling DTCs, if applicable, is contained in the supporting text for that DTC.
2. 2 Anytime a control module is reprogrammed or the diagnostic trouble codes are cleared as part of a repair procedure, all the I/M system status indicators will reset to NO.
3. 3 Use discretion when determining whether the entire system set procedure needs to be performed. For example, if the only tests that have not run are those that require the engine to be at operating temperature, then only those individual tests need to be run. There is no need to allow the engine to completely cool in order to run these tests.

Procedure

1. Perform «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM. If DTC or driveability problems were repaired using Diagnostic System Check - Engine Controls, go to step 3 . If no DTC or driveability problems were repaired using Diagnostic System Check - Engine Controls, go to next step.
2. Check for applicable Technical Service Bulletins (TSB) for software updates that may prevent Inspection/Maintenance (I/M) readiness. Perform any reprogramming or repairs indicated by TSBs. If reprogramming or repair service was required, see «INSPECTION/MAINTENANCE COMPLETE SYSTEM SET PROCEDURE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) . If reprogramming or repair service is not required, go to next step.
3. Using scan tool, observe I/M SYSTEM STATUS display. If more than one test indicates a NO status, see «INSPECTION/MAINTENANCE COMPLETE SYSTEM SET PROCEDURE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) . If only one test indicates a NO status, go to appropriate I/M system set procedure for indicated system.

This procedure satisfies enable criteria necessary to execute all monitor diagnostics, and complete trips for those particular diagnostics. When all diagnostic tests have been completed, I/M SYSTEM STATUS indicators are set to YES. Perform this test when more than one or all I/M SYSTEM STATUS indicators are set to NO.

Conditions For Running

1. Barometric (BARO) pressure is more than 74 kPa.
2. Engine Coolant Temperature (ECT) is less than 95°F (35°C).
3. Intake Air Temperature (IAT) is less than 95°F (35°C).
4. Difference between IAT and ECT is less than 11°F (6°C).
5. Battery voltage is 9-18 volts.
6. Fuel level is 1/4-3/4.

Rough road conditions may prevent some tests from running. Extreme high or low ambient temperatures may prevent tests such as Heated Oxygen Sensor (HO2S) heater and Evaporative Emission (EVAP) system from initiating. If a step is interrupted before completion, perform remaining portion of set procedure. Any portion of set procedure that requires engine at operating temperature may be repeated. This allows most diagnostics to run and remaining tests can be performed using individual system set procedure.

If vehicle has recently run, start this procedure at step 3 . This will allow tests that require the engine at operating temperature to run. Using this method allows shorter cool down periods if tests requiring a cold start do not initiate.

Scan tool can be used to monitor each I/M SYSTEM STATUS indicator during I/M complete system set procedure. When all indicators for a test step have updated to YES, testing can move on to next step even if remaining portion of test is not complete. For example, step 3 is designed to run the EVAP, secondary Air Injection (AIR), and HO2S tests. Procedure instructs technician to operate vehicle in enable conditions for 6 minutes. If all 3 tests have updated to YES within 4 minutes, it is not necessary to continue with enable conditions and testing can advance to next step.

INSPECTION/MAINTENANCE SYSTEM DTCS

The numbers below refer to the step numbers in the diagnostic procedures.

1. 1 Ensure you perform the I/M System Check before performing this test. See «INSPECTION/MAINTENANCE SYSTEM CHECK»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) . Failure to do so may result in difficulty updating the status to YES.
2. 2 This step is to run the HO2S Heater Tests and initiate the EVAP System Test. Preprogramming the scan tool will reduce the amount of time the oxygen sensor heaters operate while verifying the enable criteria. The engine control module considers the engine to be cold if the following conditions are met: ECT less than 95°F (35°C). ECT and IAT are within 11°F (6°C) of each other at start up.
3. 3 This step is to run the EVAP, AIR and the oxygen sensor tests. The EVAP test begins once the engine coolant reaches a calibrated temperature. The AIR test, if equipped, begins shortly after closed loop and the indicated speed is achieved. The oxygen sensor tests begin once the engine is at operating temperature, in closed loop fuel control, and a calibrated amount of time has elapsed.
4. 4 This step is to run the Exhaust Gas Recirculation (EGR) tests. The EGR tests are run during a gradual deceleration with a closed throttle. The vehicle speed is required in order to maintain a high, steady Manifold Absolute Pressure (MAP) signal.
5. 5 This step is to run the catalyst tests. This test runs during the idle period immediately following a cruise period that meets a minimum calibrated RPM and time period.
6. 6 Perform the individual system test for any of the systems that do not update to YES.
7. 7 The I/M System Status only reports on whether or not a diagnostic has run, not what the outcome of the test was. If any emission related DTC sets after the tests are complete, the DTC will require diagnosis.

1. Perform «INSPECTION/MAINTENANCE SYSTEM CHECK»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) . After performing inspection/maintenance system check, go to next step.
2. Preprogram scan tool with vehicle information before ignition is turned on. Ensure vehicle meets conditions under «CONDITIONS FOR RUNNING»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__conditions-for-running) . Turn off all accessories, such as A/C, blower fan, etc. Set parking brake. Ensure transmission is in Park. Start engine. Allow engine to idle for 2 minutes. Go to next step.
3. Acceleration at part throttle to 55 MPH with this speed maintained until engine reaches operating temperature. This may be up to 8-10 minutes depending on start-up coolant temperature. Continue operation under these conditions for an additional 6 minutes. Go to next step.
4. Reduce vehicle speed to 45 MPH with this speed maintained for one additional minute. Perform 4 decelerations of 25 seconds each from 45 MPH while the following criteria is maintained: Throttle is closed. No brake application on either M/T or A/T. No clutch actuation on M/T. No manual downshift. Vehicle speed remains more than 25 MPH. After each deceleration period, vehicle is returned to 45 MPH under part throttle acceleration and speed is maintained for 15 seconds. When complete, go to next step.
5. Accelerate at part throttle to 45-55 MPH. Maintain this speed for 2 minutes. Decelerate to zero MPH. Allow engine to idle for 2 minutes while the following criteria is maintained: Service brake depressed. Transmission in Drive (A/T). Transmission in Neutral (M/T) with clutch pedal depressed. When complete, go to next step.
6. Using scan tool, observe I/M SYSTEM STATUS display. If all I/M SYSTEM STATUS indicators update to YES, go to next step. If all I/M SYSTEM STATUS indicators do not update to YES, see INSPECTION/MAINTENANCE SET PROCEDURE for indicated systems.
7. Using scan tool, observe emission related DTC portion of I/M SYSTEM STATUS display. If scan tool indicates any emission related DTCs, see «DIAGNOSTIC TROUBLE CODE INDEX»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. If scan tool does not indicate emission related DTCs, system is okay.

This test satisfies the enable criteria necessary to execute I/M readiness diagnostics for the Catalyst System. The test may be used to set the I/M System Status indicators to YES. Ensure that the vehicle meets the requirements listed in Conditions for Running before performing this test. Failure to meet the necessary requirements may produce inaccurate test results.

1. Barometric (BARO) pressure is more than 74 kPa.
2. Engine coolant is 176-248°F (80-120°C).
3. Intake Air Temperature (IAT) is 5-167°F (-15-75°C).
4. Engine is in Closed Loop.
5. Engine has run for 6-8 minutes off idle.
6. Battery voltage is 9-16 volts.

The control module runs a maximum of 6 tests per trip until the CATALYST SYSTEM STATUS updates to YES. If the status does not update, the test outlined in this procedure can be repeated until the I/M SYSTEM STATUS updates to YES.

I/M SYSTEM STATUS does not indicate whether test has passed or failed, only that a decision was made. When all diagnostics for a specific system have run and passed, I/M SYSTEM STATUS will update to YES. If a test for a specific system has failed, I/M SYSTEM STATUS will update to YES, indicating a determination was made, even if all required tests have not run. When a failure occurs, emission related DTC portion of I/M SYSTEM STATUS display will indicate MIL is requested. I/M SYSTEM STATUS also registers number of DTCs.

First failure of a type "B" DTC does not constitute a final determination of pass or fail, and will not update I/M SYSTEM STATUS to YES. A second trip is required, and all conditions to run must be met in order for test to run again. These conditions may include a partial to complete engine cool down. I/M SYSTEM STATUS will update only when an emission related DTC fails second time, or when all tests pass.

If there is an impending failure, system may require more time to run diagnostic than was allotted in set procedure. If test does not run after numerous attempts and no DTC is set, review appropriate scan tool data list and service information for an indication of why test does not complete. Some tests may abort due to changes in conditions while test is running. For example, changes in engine load, such as a cooling fan or an A/C compressor clutch turning on, may cause the test to abort. If a diagnostic test is difficult to run, observe I/M SYSTEM STATUS display while maintaining necessary enable conditions until system status updates to YES.

The numbers below refer to the step numbers in the diagnostic procedures.

1. 1 Ensure you perform the I/M System Check before performing this test. See «INSPECTION/MAINTENANCE SYSTEM CHECK»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) . Failure to do so may result in difficulty updating the status to YES.
2. 2 The catalyst test runs during the idle period immediately following the cruise period.
3. 3 This step is to identify a first failure of a type "B" DTC. A DTC only appears on the I/M System Status display when the DTC becomes a Malfunction Indicator Light (MIL) illuminating DTC. This occurs on the second failure of a type "B" DTC. A first failure of a type "B" DTC will not allow the I/M System Status to update to YES. See «DIAGNOSTIC AIDS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) .
4. 4 This step is to help identify any unique or unusual criteria required to run the diagnostic test in the event the universal set procedure does not. This information is located in the service information under Conditions for Running DTC.
5. 5 The I/M System Status only reports on whether or not a diagnostic has run, not what the outcome of the test was. If any emission related DTC sets after the tests are complete, the DTC will require diagnosis.

1. Perform «INSPECTION/MAINTENANCE SYSTEM CHECK»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) . After performing inspection/maintenance system check, go to next step.
2. Ensure vehicle is operating within Conditions for Running. Turn all accessories off. Start engine and allow to idle. Operate vehicle in the following manor: Accelerate at part throttle to 55 MPH and maintain speed for 5 minutes. Decelerate to zero MPH and allow engine to idle for 2 minutes while service brake is depressed, A/T in Drive and M/T in Neutral with clutch pedal depressed. Using scan tool, monitor I/M SYSTEM STATUS. If CATALYST SYSTEM STATUS is YES, go to step 5 . If CATALYST SYSTEM STATUS is not YES, go to next step.
3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, see «DIAGNOSTIC TROUBLE CODE INDEX»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. If scan tool does not indicate any failed DTCs, go to next step.
4. Refer to «INSPECTION/MAINTENANCE SYSTEM DTCS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) to determine which DTCs are required to run in order to complete this test. Use the scan tool in order to observe the NOT RAN SINCE CODE CLEARED display. Determine which of the DTCs required for a YES status has not run. Enter the DTC number in the Specific DTC Menu of the scan tool. Operate the vehicle within «CONDITIONS FOR RUNNING»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) . Repeat the procedure until the scan tool indicates the diagnostic test has run. Repeat for any additional required DTCs that have not run. Use the scan tool in order to observe the I/M System Status Display. Did the catalyst system status update to YES? If YES, go to next step. If NO, see «DIAGNOSTIC AIDS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) .
5. Use a scan tool, in order to observe the Emission Related DTC portion of the I/M System Status display. Does the scan tool indicate any Emission Related DTCs set? If YES, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) . If NO, system is okay.

This test satisfies the enable criteria necessary to execute I/M readiness diagnostics for the exhaust gas recirculation (EGR) system. The test may be used to set the I/M System Status indicators to YES. Ensure that the vehicle meets the requirements listed in Conditions for Running before performing this test. Failure to meet the necessary requirements may produce inaccurate test results.

Conditions For Running DTC

1. Barometric (BARO) pressure is more than 70 kPa.
2. Engine Coolant Temperature (ECT) is more than 167°F (75°C).
3. System voltage is 10-18 volts.

Control module only runs EGR active tests during a gradual deceleration with a closed throttle and a vehicle speed more than 25 MPH. Several deceleration cycles may be necessary in order to accumulate a sufficient number of EGR flow samples. Procedure outlined in procedure is for a clear, flat road. If procedure is performed on a road with a slight down hill grade, test may acquire necessary sample counters in one or 2 decel trips. If test is interrupted during procedure, you may need to take more than 3 deceleration cycles to complete test. If status does not update, test outlined in this procedure can be repeated until I/M SYSTEM STATUS updates to YES.

I/M SYSTEM STATUS does not indicate whether test has passed or failed, only that a decision was made. When all of diagnostics for a specific system have run and passed, I/M SYSTEM STATUS will update to YES. If a test for a specific system has failed, I/M SYSTEM STATUS will update to YES, indicating a determination was made, even if all of the required tests have not run. When a failure occurs, emission related DTC portion of I/M SYSTEM STATUS display will indicate Malfunction Indicator Light (MIL) is requested. I/M SYSTEM STATUS also registers number of DTCs.

First failure of a type "B" DTC does not constitute a final determination of pass or fail, and will not update I/M SYSTEM STATUS to YES. A second trip is required, and all conditions to run must be met in order for test to run again. These conditions may include a partial to complete engine cool down. I/M SYSTEM STATUS will update only when an emission related DTC fails second time, or when all of tests pass.

If there is an impending failure, system may require more time to run diagnostic than was allotted in set procedure. If test does not run after numerous attempts and no DTC is set, review appropriate scan tool data list and service information for an indication of why test does not complete. Some tests may abort due to changes in conditions while test is running. For example, changes in engine load, such as a cooling fan or an A/C compressor clutch turning on, may cause test to abort. If a diagnostic test is difficult to run, observe I/M SYSTEM STATUS display while maintaining necessary enable conditions until system status updates to YES.

The numbers below refer to the step numbers in the diagnostic procedures.

1. 1 Ensure you perform the I/M System Check before performing this test. See «INSPECTION/MAINTENANCE SYSTEM CHECK»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) . Failure to do so may result in difficulty updating the status to YES.
2. 2 The EGR Active Tests are run during a gradual deceleration with a closed throttle. The vehicle speed is required in order to maintain a high, steady Manifold Absolute Pressure (MAP) signal.
3. 3 This step is to identify a first failure of a type "B" DTC. A DTC only appears on the I/M System Status display when the DTC becomes a Malfunction Indicator Light (MIL) illuminating DTC. This occurs on the second failure of a type "B" DTC. A first failure of a type "B" DTC will not allow the I/M System Status to update to YES. See «DIAGNOSTIC AIDS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) .
4. 4 This step is to help identify any unique or unusual criteria required to run the diagnostic test in the event the universal set procedure does not. See «CONDITIONS FOR RUNNING DTC»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__conditions-for-running-dtc) .
5. 5 The I/M SYSTEM STATUS only reports on whether or not a diagnostic has run, not what the outcome of the test was. If any Emission Related DTC sets after the tests are complete, the DTC will require diagnosis.

1. Perform «INSPECTION/MAINTENANCE SYSTEM CHECK»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) . After performing inspection/maintenance system check, go to next step.
2. Ensure vehicle is operating within Conditions for Running. Turn off all of accessories. Start engine and allow to idle. Accelerate at part throttle to 45 MPH and maintain speed for one minute. Perform 4 decelerations of 25 seconds each from 45 MPH while following criteria is maintained: Throttle is closed. NO brake application on either manual or automatic transmission. NO clutch actuation on a manual transmission. NO manual downshift. Vehicle speed remains more than 25 MPH. After each deceleration period, vehicle is returned to 45 MPH under part throttle acceleration and speed is maintained for 15 seconds. Using scan tool, observe I/M SYSTEM STATUS display. If EGR system status updates to YES, go to step 5 . If EGR system status did not update to YES, go to next step.
3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, see «DIAGNOSTIC TROUBLE CODE INDEX»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. If scan tool does not indicate any failed DTCs, go to next step.
4. Using scan tool, observe NOT RAN SINCE CODE CLEARED display to determine which DTCs are required to run in order to complete this test. Determine which of the DTCs required for a YES status has not run. Enter the DTC number in the Specific DTC menu of the scan tool. Operate the vehicle within «CONDITIONS FOR RUNNING DTC»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__conditions-for-running-dtc) . Repeat the procedure until the scan tool indicates the diagnostic test has run. Repeat the procedure until the scan tool indicates the diagnostic test has run. Repeat for any additional required DTCs that have not run. With the scan tool, observe the I/M System Status display. Did the EGR System Status update the EGR? If YES, go to the next step. If NO, see «DIAGNOSTIC AIDS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) .
5. Using scan tool, check for DTCs. If scan tool indicates any Emission Related DTCs are set, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) . If no codes are set system is okay.

Purpose of this test is to satisfy enable criteria necessary to execute I/M readiness diagnostics for Evaporative (EVAP) emission system. Test may be used to set I/M SYSTEM STATUS indicators to YES. Service Bay Tests are included on scan tool for some systems depending upon vehicle make and model. Test is designed to allow EVAP diagnostic tests to run in service bay conditions. Ensure vehicle meets requirements listed in enable criteria before performing either EVAP system test. Failure to meet necessary requirements may produce inaccurate test results.

Non Scan Tool Service Bay Test

1. Barometric (BARO) pressure is more than 75 kPa.
2. Fuel level is 15-85 percent.
3. Battery voltage is 10-18 volts.
4. Engine Coolant Temperature (ECT) is 39-86°F (4-30°C).
5. Intake Air Temperature (IAT) is 39-86°F (4-30°C).
6. Difference between ECT and IAT is less than 14°F (8°C).

Scan Tool Service Bay Test

1. Barometric Pressure is more than 25 kPa.
2. Engine Coolant Temperature (ECT) is less than 158°F (70°C).
3. Fuel level is 15-85 percent.
4. Battery voltage is 9-18 volts.

Extreme high or low ambient temperatures may prevent EVAP system tests from initiating. Performing a visual inspection prior to running EVAP Service Bay Test may prevent having to repeat test. A loose fuel cap may cause a Service Bay Test to abort or fail and prevent I/M SYSTEM STATUS from updating. A failed or aborted test will require vehicle to cool down in order to meet enable criteria to run another test.

I/M SYSTEM STATUS does not indicate whether test has passed or failed, only that a decision was made. When all diagnostics for a specific system have run and passed, I/M SYSTEM STATUS will update to YES. If a test for a specific system has failed, I/M SYSTEM STATUS will update to YES, indicating a determination was made, even if all required tests have not run. When a failure occurs, emission related DTC portion of I/M SYSTEM STATUS display will indicate MIL is requested. I/M SYSTEM STATUS also registers number of DTCs.

First failure of a type "B" DTC does not constitute a final determination of pass or fail, and will not update I/M SYSTEM STATUS to YES. A second trip is required, and all conditions to run must be met in order for test to run again. These conditions may include a partial to complete engine cool down. I/M SYSTEM STATUS will update only when an emission related DTC fails second time, or when all tests pass.

If there is an impending failure, system may require more time to run diagnostic than was allotted in set procedure. If test does not run after numerous attempts and no DTC is set, review appropriate scan tool data list and service information for an indication of why test does not complete. Some tests may abort due to changes in conditions while test is running. For example, changes in engine load, such as a cooling fan or an A/C compressor clutch turning on, may cause the test to abort. If a diagnostic test is difficult to run, observe I/M SYSTEM STATUS display while maintaining necessary enable conditions until system status updates to YES.

The numbers below refer to the step numbers in the diagnostic procedures.

1. 1 Perform the I/M System Check before performing this test. See «INSPECTION/MAINTENANCE SYSTEM CHECK»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) . Failure to do so may result in difficulty updating the status to YES.
2. 3 This step is to determine whether or not the EVAP System Test has passed. If the system is operating correctly, the scan tool indicates that the system has passed and the I/M SYSTEM STATUS updates to YES. If the EVAP Service Bay Test aborts because of lost enable conditions, the test can be repeated once the enable criteria is met.
3. 4 A failed DTC during the EVAP service bay test may not appear in the DTC Information display on some vehicles. The service bay test displays an indication of which test failed as a directive to the appropriate service information. Some vehicles will display the test as aborted and the first failure of type "B" DTC appears in the DTC Information.
4. 5 The EVAP System Test usually begins when the engine coolant temperature is 39-86°F (4-30°C). The vehicle should be operated moderately until this temperature is reached. The engine coolant temperature can be monitored using the scan tool.
5. 6 This step is to identify a first failure of a type "B" DTC. A DTC only appears on the I/M System Status display when the DTC becomes a Malfunction Indicator Light (MIL) illuminating DTC. This occurs on the second failure of a type "B" DTC. A first failure of a type "B" DTC will not allow the I/M System Status to update to YES. See «DIAGNOSTIC AIDS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) .
6. 7 This step is to help identify any unique or unusual criteria required to run the diagnostic test in the event the universal set procedure does not. See «CONDITIONS FOR RUNNING DTC»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) .
7. 8 The I/M System Status only reports on whether or not a diagnostic has run, not what the outcome of the test was. If any emission related DTC sets after the tests are complete, the DTC will require diagnosis.

1. Perform «INSPECTION/MAINTENANCE SYSTEM CHECK»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) . After performing inspection/maintenance system check, go to next step.
2. Using scan tool, select SPECIAL FUNCTIONS. Determine if vehicle is equipped with a Service Bay Test for EVAP system. If vehicle is equipped with EVAP Service Bay Test, go to next step. If vehicle is not equipped with EVAP Service Bay Test, go to step 5 .
3. Ensure vehicle is operating within Conditions for Running. Turn off all accessories. Following directions on scan tool, perform EVAP Service Bay Test. If EVAP system passed Service Bay Test, go to step 8 . If EVAP system did not pass Service Bay Test, go to next step.
4. Observe scan tool Service Bay Test for an indication of why test did not pass (e.g., failed DTC, test aborted, etc.). Diagnose and repair condition as necessary. After repairs, see «INSPECTION/MAINTENANCE COMPLETE SYSTEM SET PROCEDURE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) .
5. Ensure vehicle is operating within Conditions for Running. Turn off all of accessories. Once engine is started, DO NOT turn engine off for remainder of procedure until test is complete. Start and idle engine. Operate vehicle in following manner: Accelerate at part throttle to 45 MPH. Maintain speed until engine reaches operating temperature (8-10 minutes). Continue operating conditions for an additional 3 minutes after engine reaches operating temperature, or until I/M SYSTEM STATUS indicator updates to YES. If EVAP SYSTEM STATUS updates to YES, go to step 8 . If EVAP SYSTEM STATUS does not update to YES, go to next step.
6. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, see «DIAGNOSTIC TROUBLE CODE INDEX»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. If scan tool does not indicate any failed DTCs, go to next step.
7. Using scan tool, observe NOT RAN SINCE CODE CLEARED display to determine if DTCs P0440, P0442, P0446 and P1441 have run. For those DTCs that have not run, see Conditions for Running DTC in appropriate DTC under DIAGNOSTIC TESTS. Operate vehicle to meet code enable criteria until DTC(s) runs. Using scan tool, observe I/M SYSTEM STATUS display. If EVAP SYSTEM STATUS updated to YES, go to next step. If EVAP SYSTEM STATUS did not update to YES, see «DIAGNOSTIC AIDS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) .
8. Using scan tool, check for DTCs. If scan tool indicates any DTCs are set, see «DIAGNOSTIC TROUBLE CODE INDEX»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS.

Purpose of this test is to satisfy enable criteria necessary to execute I/M readiness diagnostics for oxygen sensor (O2S, HO2S) system. Test may be used to set I/M SYSTEM STATUS to YES. Ensure vehicle meets requirements listed in Conditions for Running before performing this test. Failure to meet necessary requirements may produce inaccurate test results.

1. Engine Coolant Temperature (ECT) is more than 165°F (75°C).
2. Engine is running in closed loop.
3. Engine has been running for more than 4 minutes.
4. Battery voltage is 9-18 volts.

If status does not update, repeat this test until I/M SYSTEM STATUS updates to YES.

I/M SYSTEM STATUS does not indicate whether test has passed or failed, only that a decision was made. When all diagnostics for a specific system have run and passed, I/M SYSTEM STATUS will update to YES. If a test for a specific system has failed, I/M SYSTEM STATUS will update to YES, indicating a determination was made, even if all required tests have not run. When a failure occurs, emission related DTC portion of I/M SYSTEM STATUS display will indicate MIL is requested. I/M SYSTEM STATUS also registers number of DTCs.

First failure of a type "B" DTC does not constitute a final determination of pass or fail, and will not update I/M SYSTEM STATUS to YES. A second trip is required, and all conditions to run must be met in order for test to run again. These conditions may include a partial to complete engine cool down. I/M SYSTEM STATUS will update only when an emission related DTC fails second time, or when all tests pass.

If there is an impending failure, system may require more time to run diagnostic than was allotted in set procedure. If test does not run after numerous attempts and no DTC is set, review appropriate scan tool data list and service information for an indication of why test does not complete. Some tests may abort due to changes in conditions while test is running. For example, changes in engine load, such as a cooling fan or an A/C compressor clutch turning on, may cause the test to abort. If a diagnostic test is difficult to run, observe I/M SYSTEM STATUS display while maintaining necessary enable conditions until system status updates to YES.

The numbers below refer to the step numbers in the diagnostic procedures.

1. 1 Ensure you perform the I/M System Check before performing this test. See «INSPECTION/MAINTENANCE SYSTEM CHECK»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) . Failure to do so may result in difficulty updating the status to YES.
2. 2 The oxygen sensor tests begin shortly after the indicated speed is achieved. The engine RPM may be too low in Overdrive on manual transmission vehicles. If difficulty is encountered updating the status, operate the vehicle in the recommended gear during the test.
3. 3 This step is to identify a first failure of a type "B" DTC. A DTC only appears on the I/M SYSTEM STATUS display when the DTC becomes a Malfunction Indicator Light (MIL) illuminating DTC. This occurs on the second failure of a type "B" DTC. A first failure of a type "B" DTC will not allow the I/M SYSTEM STATUS to update to YES. See «DIAGNOSTIC AIDS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) .
4. 4 This step is to help identify any unique or unusual criteria required to run the diagnostic test in the event the universal set procedure does not. See «CONDITIONS FOR RUNNING»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) .
5. 5 The I/M System Status only reports on whether or not a diagnostic has run, not what the outcome of the test was. If any Emission Related DTC sets after the tests are complete, the DTC will require diagnosis.

1. Perform «INSPECTION/MAINTENANCE SYSTEM CHECK»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) . After performing inspection/maintenance system check, go to next step.
2. Verify vehicle is operating within Conditions for Running. Turn off all accessories. Start and idle engine. Accelerate at part throttle to 45-55 MPH. Maintain this speed for 6 minutes or until I/M SYSTEM STATUS updates to YES. M/T may require operation in 4th or 5th gear. Using scan tool, review I/M SYSTEM STATUS display. If HO2S SYSTEM STATUS update to YES, go to step 5 . If HO2S SYSTEM STATUS does not update to YES, go to next step.
3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, see «DIAGNOSTIC TROUBLE CODE INDEX»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. If scan tool does not indicate any failed DTCs, go to next step.
4. Refer to «DIAGNOSTIC TROUBLE CODE INDEX»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) to determine which DTCs are required to run in order to complete this test. Use the scan tool in order to observe the NOT RAN SINCE CODE CLEARED display. Determine which of the DTCs required for a YES status has not run. Enter the DTC number in the Specific DTC menu of the scan tool. Operate the vehicle within the «CONDITIONS FOR RUNNING»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) . Repeat the procedure until the scan tool indicates the diagnostic test has run. Repeat the procedure until the scan tool indicates the diagnostic test has run. Repeat for any additional required DTCs that have not run. Use a scan tool in order to observe the I/M System Status display. Did the HO2S/O2S System Status update to YES? If YES, go to next step. If NO, see «DIAGNOSTIC AIDS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) .
5. Using scan tool, check for DTCs. If scan tool indicates any DTCs are set, see «DIAGNOSTIC TROUBLE CODE INDEX»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS.

Purpose of this test is to satisfy enable criteria necessary to execute I/M readiness diagnostics for heated oxygen sensor (HO2S) system. The test may be used to set I/M SYSTEM STATUS to YES. Ensure vehicle meets enable criteria before performing this test. Failure to meet necessary requirements may produce inaccurate test results.

1. Engine Coolant Temperature (ECT) is less than 95°F (35°C).
2. Intake Air Temperature (IAT) is less than 95°F (35°C).
3. Difference between IAT and ECT is less than 11°F (6°C).
4. Battery voltage is 9-18 volts.

HO2S heater tests will normally run within 2 minutes allotted in procedure. If there is an indeterminate condition, test may take up to 8 minutes on some vehicles before a decision of pass or fail is made. If the test does not update within allotted period of time, continue operation within enable conditions until test updates to YES. If test does not update to YES, it may have failed or aborted due to loss of enabling conditions. Extremely high ambient temperatures may prevent HO2S heater test from initiating.

I/M SYSTEM STATUS does not indicate whether test has passed or failed, only that a decision was made. When all diagnostics for a specific system have run and passed, I/M SYSTEM STATUS will update to YES. If a test for a specific system has failed, I/M SYSTEM STATUS will update to YES, indicating a determination was made, even if all required tests have not run. When a failure occurs, emission related DTC portion of I/M SYSTEM STATUS display will indicate MIL is requested. I/M SYSTEM STATUS also registers number of DTCs.

First failure of a type "B" DTC does not constitute a final determination of pass or fail, and will not update I/M SYSTEM STATUS to YES. A second trip is required, and all conditions to run must be met in order for test to run again. These conditions may include a partial to complete engine cool down. I/M SYSTEM STATUS will update only when an emission related DTC fails second time, or when all tests pass.

If there is an impending failure, system may require more time to run diagnostic than was allotted in set procedure. If test does not run after numerous attempts and no DTC is set, review appropriate scan tool data list and service information for an indication of why test does not complete. Some tests may abort due to changes in conditions while test is running. For example, changes in engine load, such as a cooling fan or an A/C compressor clutch turning on, may cause the test to abort. If a diagnostic test is difficult to run, observe I/M SYSTEM STATUS display while maintaining necessary enable conditions until system status updates to YES.

The numbers below refer to the step numbers in the diagnostic procedures.

1. 1 Ensure you perform the I/M System Check before performing this test. See «INSPECTION/MAINTENANCE SYSTEM CHECK»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) . Failure to do so may result in difficulty updating the status to YES.
2. 2 Preprogramming the scan tool will reduce the amount of time the oxygen sensor heaters operate while verifying the enable criteria.
3. 3 This step is to identify a first failure of a type "B" DTC. A DTC only appears on the I/M System Status display when the DTC becomes a Malfunction Indicator Light (MIL) illuminating DTC. This occurs on the second failure of a type "B" DTC. A first failure of a type "B" DTC will not allow the I/M System Status to update to YES. See «DIAGNOSTIC AIDS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) .
4. 4 This step is to help identify any unique or unusual criteria required to run the diagnostic test in the event the universal set procedure does not. This information is located in the service information under Conditions for Running DTC.
5. 5 The I/M SYSTEM STATUS only reports on whether or not a diagnostic has run, not what the outcome of the test was. If any emission related DTC sets after the tests are complete, the DTC will require diagnosis.

1. Perform «INSPECTION/MAINTENANCE SYSTEM CHECK»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) . After performing inspection/maintenance system check, go to next step.
2. Preprogram scan tool with vehicle information before ignition is turned on. Verify vehicle is operating within Conditions for Running. Set vehicle parking brake. Ensure transmission is in Park. Turn off all of accessories. Start the engine. Allow engine to idle for 2 minutes or until I/M SYSTEM STATUS indicator updates to YES. Using scan tool, observe I/M SYSTEM STATUS display. If HO2S HEATER SYSTEM STATUS updated to YES, go to step 5 . If HO2S HEATER SYSTEM STATUS did not update to YES, go to next step.
3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, see «DIAGNOSTIC TROUBLE CODE INDEX»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. If scan tool does not indicate any failed DTCs, go to next step.
4. Refer to «DIAGNOSTIC TROUBLE CODE INDEX»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) to determine which DTCs are required to run in order to complete this test. Use the scan tool in order to observe the NOT RAN SINCE CODE CLEARED display. Determine «DIAGNOSTIC AIDS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) .
5. Using scan tool, check for DTCs. If scan tool indicates any DTCs are set, see «DIAGNOSTIC TROUBLE CODE INDEX»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS.

SUMMARY

If no hard fault codes are present, driveability symptoms exist or intermittent DTC(s) exist, proceed to TROUBLE SHOOTING - NO CODES - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article for diagnosis by symptom (i.e., ROUGH IDLE, NO-START, etc.) or intermittent diagnostic procedures.

If no Diagnostic Trouble Codes (DTCs) are present and a no-start condition exists, proceed to NO-START DIAGNOSIS in BASIC DIAGNOSTIC PROCEDURES - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LE SABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no DTCs are present and a driveability condition exists, diagnosis by symptom (i.e., ROUGH IDLE, ENGINE STALLS, etc.). See SYMPTOMS in TROUBLE SHOOTING - NO CODES - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.

DIAGNOSTIC TROUBLE CODE DEFINITIONS

Note. Use of a Tech 2 or generic OBD-II scan tool is required to retrieve DTCs. Refer to user reference manual supplied with scan tool.

DIAGNOSTIC TROUBLE CODE INDEX

Scheme 1

Scheme 2

Scheme 3

Scheme 4

Scheme 5

Scheme 6

Scheme 7

Scheme 8

Scheme 9

Scheme 10

Scheme 11

Scheme 12

Scheme 13

Scheme 14

Scheme 15

Scheme 16

Scheme 17

Scheme 18

Scheme 19

Scheme 20

Scheme 21

Scheme 22

Scheme 23

Scheme 24

Scheme 25

Scheme 26

Scheme 27

Scheme 28

Scheme 29

Scheme 30

Scheme 31

Scheme 32

Scheme 33

Scheme 34

Scheme 35

Scheme 36

Scheme 37

Scheme 38

Scheme 39

Scheme 40

Scheme 41

Scheme 42

Scheme 43

Scheme 44

Scheme 45

Scheme 46

Scheme 47

Scheme 48

Scheme 49

Scheme 50

Scheme 51

Scheme 52

Scheme 53

Scheme 54

Scheme 55

Scheme 56

Scheme 57

Scheme 58

Scheme 59

Scheme 60

Scheme 61

Scheme 62

Scheme 63

Scheme 64

Scheme 65

Scheme 66

Scheme 67

Scheme 68

Scheme 69

Scheme 70

Scheme 71

Scheme 72

Scheme 73

Scheme 74

Scheme 75

Scheme 76

Scheme 77

Scheme 78

Scheme 79

Scheme 80

Scheme 81

Scheme 82

Scheme 83

Scheme 84

Scheme 85

Scheme 86

Scheme 87

Scheme 88

Scheme 89

Scheme 90

Scheme 91

Scheme 92

Scheme 93

Scheme 94

Scheme 95

Scheme 96

Scheme 97

Scheme 98

Scheme 99

Scheme 100

Scheme 101

Scheme 102

Scheme 103

Scheme 104

Scheme 105

Scheme 106

Scheme 107

Scheme 108

Scheme 109

Scheme 110

Scheme 111

Scheme 112

Scheme 113

Scheme 114

Scheme 115

Scheme 116

Scheme 117

Scheme 118

Scheme 119

Scheme 120

Scheme 121

Scheme 122

Scheme 123

Scheme 124

Scheme 125

Scheme 126

Scheme 127

Scheme 128

Scheme 129

Scheme 130

Scheme 131

Scheme 132

Scheme 133

Scheme 134

Scheme 135

Scheme 136

Scheme 137

Scheme 138

Scheme 139

Scheme 140

Scheme 141

Scheme 142

Scheme 143

Scheme 144

Scheme 145

Scheme 146

Scheme 147

Scheme 148

Scheme 149

Scheme 150

Scheme 151

Scheme 152

Scheme 153

Scheme 154

Scheme 155

Scheme 156

Scheme 157

Scheme 158

Scheme 159

Scheme 160

Scheme 161

Scheme 162

Scheme 163

Scheme 164

Scheme 165

Scheme 166

Scheme 167

Scheme 168

Scheme 169

Scheme 170

Scheme 171

Scheme 172

Scheme 173

Scheme 174

Scheme 175

Scheme 176

Scheme 177

Scheme 178

Scheme 179

Scheme 180

Scheme 181

Scheme 182

Scheme 183

Scheme 184

Scheme 185

Scheme 186

Scheme 187

Scheme 188

Scheme 189

Scheme 190

Scheme 191

Scheme 192

Scheme 193

Scheme 194

Scheme 195

Scheme 196

Scheme 197

Scheme 198

Scheme 199

Scheme 200

Scheme 201

Scheme 202

Scheme 203

Scheme 204

Scheme 205

Scheme 206

Scheme 207

Scheme 208

Scheme 209

Scheme 210

Scheme 211

Scheme 212

Scheme 213

Scheme 214

Scheme 215

Scheme 216

Scheme 217

Scheme 218

Scheme 219

Scheme 220

Scheme 221

Scheme 222

Scheme 223

Scheme 224

Scheme 225

Scheme 226

Scheme 227

Scheme 228

Scheme 229

Scheme 230

Scheme 231

Scheme 232

Scheme 233

Scheme 234

Scheme 235

Scheme 236

Scheme 237

Scheme 238

Scheme 239

Scheme 240

Scheme 241

Scheme 242

Scheme 243

Scheme 244

Scheme 245

Scheme 246

Scheme 247

Scheme 248

Scheme 249

Scheme 250

Scheme 251

Scheme 252

MIL INOPERATIVE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM.

Ignition voltage is supplied to the Malfunction Indicator Light (MIL). The Powertrain Control Module (PCM) turns the MIL ON by grounding the MIL control circuit. There should be a steady MIL with ignition ON and engine OFF.

MIL Operation

The MIL is located on the instrument panel.

MIL Function

1. The MIL informs the driver that a malfunction has occurred and the vehicle should be taken in for service as soon as possible.
2. The MIL illuminates during a bulb test and a system test.
3. A Diagnostic Trouble Code (DTC) will be stored if a MIL is requested by the PCM.

MIL Illumination

1. The MIL will illuminate with ignition switch on and the engine not running.
2. The MIL will turn off when the engine is started.
3. The MIL will remain ON if the self-diagnostic system has detected a malfunction.
4. The MIL may turn OFF if the malfunction is not present.
5. If the MIL is illuminated and then the engine stalls, the MIL will remain illuminated so long as the ignition switch is ON.
6. If the MIL is not illuminated and the engine stalls, the MIL will not illuminate until the ignition switch is cycled OFF, then ON.

The numbers below refer to the step numbers in the diagnostic procedures.

1. 4 This step tests for a short to voltage on the MIL control circuit. With the fuse removed there should be no voltage on the MIL control circuit.

Scheme 253

Scheme 254

IPC TERMINAL IDENTIFICATION

MIL IGNITION VOLTAGE FEED

MIL ALWAYS ON

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM.

The battery positive voltage is supplied directly to the Malfunction Indicator Light (MIL). The Powertrain Control Module (PCM) turns the MIL ON by grounding the MIL control circuit.

The MIL is located on the instrument panel.

MIL Function

1. The MIL informs the driver that a malfunction has occurred and the vehicle should be taken in for service as soon as possible.
2. The MIL illuminates during a bulb test and a system test.
3. A Diagnostic Trouble Code (DTC) will be stored if a MIL is requested by the diagnostic.

MIL Illumination

1. The MIL will illuminate with ignition switch on and the engine not running.
2. The MIL will turn OFF when the engine is started.
3. The MIL will remain on if the self-diagnostic system has detected a malfunction.
4. The MIL may turn OFF if the malfunction is not present.
5. If the MIL is illuminated and then the engine stalls, the MIL will remain illuminated so long as the ignition switch is ON.
6. If the MIL is not illuminated and the engine stalls, the MIL will not illuminate until the ignition switch is cycled OFF, then ON.

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

The numbers below refer to the step numbers in the diagnostic procedures.

1. 2 The step determines if the condition is with the MIL control circuit or the PCM.

Scheme 255

DIAGNOSTIC TESTS

Note. Before clearing DTCs, perform Diagnostic System Check - Engine Controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS . Record FREEZE FRAME and FAILURE RECORDS for reference during testing. Data will be erased when DTCs are cleared.

DTC P0101: MAF SYSTEM PERFORMANCE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

The Mass Airflow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The Powertrain Control Module (PCM) uses the MAF sensor signal to provide the correct fuel delivery for all engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle condition. A large quantity of air entering the engine indicates an acceleration or high load condition. The MAF sensor has the following circuits

1. An ignition 1 voltage circuit.
2. A ground circuit.
3. A signal circuit.

The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage in order to produce a frequency based on inlet air flow through the sensor bore. The frequency varies within a range of around 2,000 Hertz at idle to about 10,000 Hertz at maximum engine load. The PCM uses the following sensor inputs in order to calculate a predicted MAF value

1. The Barometric (BARO) pressure at key on.
2. The Manifold Absolute Pressure (MAP).
3. The Intake Air Temperature (IAT).
4. The Engine Coolant Temperature (ECT).
5. The Throttle Position (TP).
6. The engine speed (RPM).

The PCM compares the actual MAF sensor frequency signal to the predicted MAF value. This comparison will determine if the signal is stuck based on a lack of variation, or is too low or too high for a given operating condition. DTC P0101 sets if the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value. If the PCM detects the actual value is not within a predetermined range of the calculated MAF value DTC P0101 sets.

1. DTCs P0102, P0103, P0107, P0108, P0121, P0122, P0123, P0401, P0403, P0404, P0405, P0440, P0442, P0443, P0446, P0449, P1106, P1107, P1121, P1122, P1404, and P1441 are not set.
2. Engine is running.
3. Ignition 1 signal is 9-18 volts.
4. TP sensor angle is less than 15 percent (VIN K) or less than 30 percent (VIN 1).
5. The change in the TP sensor angle is less than 5 percent.
6. The traction control is inactive, if equipped.
7. The MAP sensor is less than 80 kPa.
8. The change in the MAP sensor is less than 5 kPa.
9. The conditions are met for more than 2 seconds.

Conditions For Setting DTC

The PCM detects that the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value for more than 40 seconds.

Action Taken When DTC Sets

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

Conditions For Clearing MIL/DTC

1. The control module turns OFF the 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 MIL and DTC with a scan tool.

1. Inspect the harness of the MAF sensor to verify that it is not routed too close to the secondary ignition wires/coils, solenoids, relays, or motors.
2. A low minimum air rate through the sensor bore at idle or during deceleration may cause this DTC to set. Inspect for any deposits on the throttle plate or in the throttle bore or a vacuum leak downstream of the MAF sensor.
3. Inspect for any contamination or debris on the sensing elements of the MAF sensor.
4. Inspect the air induction system for any water intrusion. Any water that reaches the MAF sensor will skew the sensor and may cause this DTC to set.
5. A wide open throttle acceleration from a stop should cause the MAF sensor parameter on the scan tool to increase rapidly. This increase should be from 7-12 g/s at idle to 150 g/s or more at the time of the 1-2 shift. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system.
6. Inspect for a skewed or stuck ECT sensor.
7. Inspect for a skewed or stuck TP sensor.
8. A high resistance of 15 ohms or more on the ignition 1 voltage circuit may cause this DTC to set. A high resistance may cause a driveability concern before this DTC sets.
9. The barometric pressure that is used in order to calculate the predicted mass airflow value is initially based on the MAP sensor at key ON. When the engine is running the BARO sensor value is continually updated near wide open throttle. A skewed MAP sensor will cause the calculated mass airflow value to be inaccurate and may result in a no start condition. The value shown for the MAP sensor display varies with the altitude. With the ignition ON and the engine OFF, 103 kPa is the approximate value near sea level. This value will decrease by approximately 3 kPa for every 1000 feet (305 meters) of altitude.
10. A high resistance on the low reference circuit of the MAP sensor may cause this DTC to set.

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

The numbers below refer to the step numbers in the diagnostic procedures.

1. 5 This step will determine if the MAP sensor pressure is within the proper range for a given altitude.
2. 6 This step will determine if the MAP sensor pressure is within the proper range at idle.
3. 7 This step will determine if the MAP sensor responds properly to the change in manifold pressure.
4. 8 This step will determine if the TP sensor is operating properly.
5. 9 This step will determine if any mechanical faults have caused this DTC to set.
6. 10 This voltage drop test will determine if high resistance has caused this DTC to set.

Scheme 256

Scheme 257

DTC P0102: MAF SENSOR CIRCUIT - LOW FREQUENCY

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

The Mass Airflow (MAF) sensor is an airflow meter that measures the amount of air entering the engine. The Powertrain Control Module (PCM) uses the MAF sensor signal in order to provide the correct fuel delivery for a wide range of engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle. A large quantity of air entering the engine indicates an acceleration or high load condition. The MAF sensor has the following circuits

1. An ignition 1 voltage circuit
2. A ground circuit
3. A signal circuit

The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage in order to produce a frequency based on inlet air flow through the sensor bore. The frequency varies within a range of around 2,000 Hertz at idle to about 10,000 Hertz at maximum engine load. DTC P0102 sets if the PCM detects a frequency signal lower than the possible range of a properly operating MAF sensor.

1. Engine is cranking or running.
2. Engine speed is more than 50 RPM.
3. Ignition 1 signal is greater than 8 volts.
4. Idle Air Control (IAC) position is more than 5 counts.
5. Conditions are present for greater than 0.5 second.

DTC sets when MAF sensor frequency signal is less than 1200 Hz for more than 12 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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 the harness of the MAF sensor to verify that it is not routed too close to the secondary ignition wires or coils, solenoids, relays, or motors.
2. Inspect for any contamination or debris on the sensing elements of the MAF sensor.
3. A wide open throttle acceleration from a stop should cause the MAF sensor parameter on the scan tool to increase rapidly. This increase should be from 7-12 g/s at idle to 150 g/s or more at the time of the 1-2 shift. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system.
4. A high resistance of 20 ohms or more on the ground circuit of the MAF sensor may cause this DTC to set. A high resistance may cause a driveability concern before this DTC sets.

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

The numbers below refer to the step number of the diagnostic procedure.

1. 5 This step will determine if any mechanical faults have caused this DTC to set.
2. 7 This voltage drop test will determine if high resistance has caused this DTC to set.
3. 9 This step verifies the signal circuit from the MAF sensor electrical connector to the PCM.
4. 10 This step tests the signal circuit of the MAF sensor for a short to another 5-volt reference circuit.
5. 12 This step will determine which portion of the circuit or which component is shorted to ground.
6. 15 This step verifies that the signal circuit is not shorted to any other PCM circuit.

Scheme 258

Scheme 259

Scheme 260

DTC P0103: MAF SENSOR CIRCUIT - HIGH FREQUENCY

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

The Mass Airflow (MAF) sensor is an airflow meter that measures the amount of air entering the engine. The Powertrain Control Module (PCM) uses the MAF sensor frequency signal in order to provide the correct fuel delivery for a wide range of engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle. A large quantity of air entering the engine indicates an acceleration or high load condition. The MAF sensor has the following circuits

1. An ignition 1 voltage circuit.
2. A ground circuit.
3. A signal circuit.

The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage in order to produce a frequency based on inlet air flow through the sensor bore. The frequency varies within a range of around 2,000 Hertz at idle to about 10,000 Hertz at maximum engine load. DTC P0103 sets if the PCM detects a frequency signal higher than the possible range of a properly operating sensor.

1. Engine is cranking or running.
2. Engine speed is more than 50 RPM.
3. Ignition 1 signal is more than 8 volts.
4. Idle Air Control (IAC) position is more than 5 counts.
5. Conditions are present for more than 0.5 second.

DTC sets when MAF sensor frequency signal is more than 11,500 Hz for more than 12 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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 the air induction system for any water intrusion. The water rapidly cools the hot sensing elements in the sensor causing a false indication of excessive air flow. Any water that reaches the MAF sensor will skew the sensor and may cause this DTC to set.
2. A poor connection in the ignition 1 voltage circuit of the MAF sensor may cause this DTC to set.

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

The numbers below refer to the step numbers in the diagnostic procedures.

1. 3 This step tests for Electromagnetic Interference (EMI) on the signal circuit of the MAF sensor. A frequency reading with the MAF sensor disconnected indicates an EMI related fault or a poor connection. Disconnecting the MAF sensor may set additional related DTCs.
2. 4 This step will determine if incorrect harness routing has caused this DTC to set.
3. 5 This step will determine if water intrusion has caused this DTC to set.

Scheme 261

DTC P0107: MAP SENSOR CIRCUIT - LOW VOLTAGE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

1. VIN K The Manifold Absolute Pressure (MAP) sensor responds to changes in intake manifold pressure which gives an indication of the engine load. The MAP sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. The Powertrain Control Module (PCM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit and provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the MAP Sensor signal circuit which is relative to the pressure changes in the manifold. With low MAP such as during idle or deceleration, the PCM should detect a low MAP sensor signal voltage. With high MAP such as ignition ON, engine OFF or Wide-Open Throttle (WOT), the PCM should detect a high MAP sensor signal voltage. This MAP sensor will indicate pressure between 10-104 kPa. The MAP sensor is also used in order to calculate the Barometric Pressure (BARO) when the ignition switch is turned ON, with the engine OFF. The BARO reading may also be updated whenever the engine is operated at WOT. The PCM monitors the MAP sensor signal for voltage outside of the normal range. If the PCM detects a MAP sensor signal voltage that is excessively low, DTC P0107 sets.
2. VIN 1 The MAP sensor responds to changes in intake manifold pressure which gives an indication of the engine load. The MAP sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. The PCM supplies 5 volts to the MAP sensor on the 5-volt reference circuit and provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the MAP Sensor signal circuit which is relative to the pressure changes in the manifold. With low MAP such as during idle or deceleration, the PCM should detect a low MAP sensor signal voltage. With high MAP such as WOT, the PCM should detect a high MAP sensor signal voltage. This MAP sensor will indicate pressure between 8-208 kPa. The MAP sensor is also used in order to calculate the BARO when the ignition switch is turned ON, with the engine OFF. The PCM monitors the MAP sensor signal for voltage outside of the normal range. If the PCM detects a MAP sensor signal voltage that is excessively low, DTC P0107 sets.

1. Ignition is on.
2. DTCs P0121, P0122 or P0123 are not set.
3. Throttle angle is more than zero percent when engine speed is less than 1000 RPM.
4. Throttle angle is more than 10 percent when engine speed is more than 1000 RPM.

The PCM detects that the MAP sensor signal voltage is less than 0.1 volt for more than 7 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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 in the diagnostic procedures.

1. 4 Operate the vehicle within the same conditions as when the DTC failed. If you cannot duplicate the DTC, the information included in the Freeze Frame/Failure Records data can aid in locating an intermittent condition.
2. 5 This step determines if voltage is available to the sensor. If also determined if there is sufficient current flow in the circuit.

Scheme 262

Scheme 263

DTC P0108: MAP SENSOR CIRCUIT - HIGH VOLTAGE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

VIN K

1. The Manifold Absolute Pressure (MAP) sensor responds to changes in the intake manifold pressure, which gives an indication of the engine load. The MAP sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. The Powertrain Control Module (PCM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit, and provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the MAP sensor signal circuit, which is relative to the pressure changes in the manifold. With low MAP, such as during idle or deceleration, the PCM should detect a low MAP sensor signal voltage. With high MAP, such as during ignition ON, engine OFF or wide open throttle (WOT), the PCM should detect a high MAP sensor signal voltage. This MAP sensor will indicate pressure between 10-104 kPa. The MAP sensor is also used in order to calculate the Barometric Pressure (BARO) when the ignition switch is turned ON, with the engine OFF. The BARO reading may also be updated whenever the engine is operated at wide-open throttle. The PCM monitors the MAP sensor signal for voltage outside of the normal range. If the PCM detects a MAP sensor signal voltage that is excessively high, DTC P0108 sets.

VIN 1

1. The MAP sensor responds to changes in intake manifold pressure which gives an indication of the engine load. The MAP sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. The PCM supplies 5 volts to the MAP sensor on the 5-volt reference circuit, and provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the MAP sensor signal circuit, which is relative to the pressure changes in the manifold. With low MAP, such as during idle or deceleration, the PCM should detect a low MAP sensor signal voltage. With high MAP, such as WOT, the PCM should detect a high MAP sensor signal voltage. This MAP sensor will indicate pressure between 8-208 kPa. The MAP sensor is also used in order to calculate the BARO when the ignition switch is turned ON, with the engine OFF. The PCM monitors the MAP sensor signal for voltage outside of the normal range. If the PCM detects a MAP sensor signal voltage that is excessively high, DTC P0108 sets.

VIN K

1. Engine has been running for a length of time that is determined by start-up coolant temperature. Length of time ranges from 2 minutes at less than -22°F (-30°C) to one second at more than 86°F (30°C).
2. Throttle angle is less than 2 percent when engine speed is less than 1500 RPM.
3. Throttle angle is less than 10 percent when engine speed is more than 1500 RPM.
4. DTCs P0121, P0122 or P0123 are not set.

VIN 1

1. Engine has been running for a length of time that is determined by start-up coolant temperature. Length of time ranges from 2 minutes at less than -22°F (-30°C) to one second at more than 86°F (30°C).
2. Throttle angle is less than 2 percent when engine speed is less than 900 RPM.
3. Throttle angle is less than 30 percent when engine speed is more than 900 RPM.
4. DTCs P0121, P0122 and P0123 are not set.

The PCM detects that the MAP sensor signal voltage is more than 4.2 volts for 7 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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 in the diagnostic procedures.

1. 2 This step tests for improper Throttle Position (TP) sensor operation.
2. 4 If you cannot duplicate the DTC, the information included in the Freeze Frame/Failure Records can aid in locating an intermittent condition.

Scheme 264

Scheme 265

DTC P0112: IAT SENSOR CIRCUIT - LOW VOLTAGE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

The Intake Air Temperature (IAT) sensor is a variable resistor. The IAT sensor has a signal circuit and a low reference circuit. The IAT sensor measures the temperature of the air entering the engine. The Powertrain Control Module (PCM) supplies 5 volts to the IAT signal circuit and a ground for the IAT low reference circuit. When the IAT sensor is cold, the sensor resistance is high. When the air temperature increases, the sensor resistance decreases. With high sensor resistance, the PCM detects a high voltage on the IAT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the IAT signal circuit. If the PCM detects an excessively low IAT signal voltage, indicating a high temperature, DTC P0112 sets.

1. DTCs P0101, P0102, P0103, P0116, P0117, P0118, P0125, P0128, P0502, or P0503 are not set.
2. Engine has been running for more than 10 seconds.
3. Vehicle speed is more than 25 MPH.

The PCM detects that the IAT sensor parameter is more than 253°F (123°C) for more than 20 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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.

When the vehicle is at ambient temperature, the IAT sensor and Engine Coolant Temperature (ECT) sensor temperatures should be relatively close to each other.

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

Scheme 266

DTC P0113: IAT SENSOR CIRCUIT - HIGH VOLTAGE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

The Intake Air Temperature (IAT) sensor is a variable resistor. The IAT sensor has a signal circuit and a low reference circuit. The IAT sensor measures the temperature of the air entering the engine. The Powertrain Control Module (PCM) supplies 5 volts to the IAT signal circuit and a ground for the IAT low reference circuit. When the IAT sensor is cold, the sensor resistance is high. When the air temperature increases, the sensor resistance decreases. With high sensor resistance, the PCM detects a high voltage on the IAT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the IAT signal circuit. If the PCM detects an excessively high IAT signal voltage, indicating a low temperature, DTC P0113 sets.

1. DTCs P0116, P0117, P0118, P0125, P0128, P0502, or P0503 are not set.
2. Engine has been running for more than 3 minutes.
3. Vehicle speed is less than 5 MPH.
4. Mass Airflow (MAF) is less than 8 g/s.
5. Engine Coolant Temperature (ECT) is more than 140°F (60°C).

IAT is less than -36°F (-38°C) for more than 60 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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.

When the vehicle is at ambient temperature the IAT sensor and ECT sensor temperatures should be relatively close to each other.

If a short to a separate 5-volt source occurs, this DTC may set. If this is found to be a problem, a continuity test to all other PCM circuits will be necessary to diagnose specific circuit.

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

The number below refers to the step number in the diagnostic procedures.

1. 6 This step tests for the proper operation of the circuit in the low voltage range.

Scheme 267

Scheme 268

DTC P0116: ECT SENSOR CIRCUIT PERFORMANCE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

The Engine Coolant Temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The Powertrain Control Module (PCM) supplies 5 volts to the signal circuit. When coolant temperatures are low, resistance is high. When coolant temperatures are high, the resistance is low. The PCM uses this input for engine controls and the enabling criteria for the diagnostics. The PCM will record the amount of time that the engine is off. At restart, the PCM will compare the temperature difference between the ECT and the Intake Air Temperature (IAT). If the temperature difference is not within the calculated amount after the predetermined soak time, this DTC will set. Before failing this test, the PCM will inspect for the presence of a block heater.

1. The ignition is on.
2. The vehicle has a minimum soak time of 8 hours.
3. DTCs P0112, P0113, P0117, P0118, P0125, P0128, P0601, P0602, P1621, or P1683 are not set.

The PCM may detect a temperature difference between the ECT and the IAT of more than 180°F (100°C).

The time spent cranking the engine, within starting is more than 5 seconds with a temperature difference between the ECT sensor and the IAT sensor of more than 27°F (15°C).

The PCM detects a temperature difference between the ECT sensor of more than 27°F (15°C), then the vehicle must be driven for 5 minutes over 15 MPH. If the IAT sensor temperature decreases more than 12.6°F (7°C) then a block heater is detected and the test is aborted. If the IAT sensor temperature does not decrease, then a block heater was not detected and DTC P0116 sets.

1. The control module illuminates the Malfunction Indicator Light (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 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.

DTC P0116 is designed to detect an ECT sensor that is skewed high.

An IAT sensor that is skewed low could cause this DTC to set.

When checking the ECT sensor, the Temperature vs. Resistance table should be used in order to determine if a skewed sensor is the problem. See SENSOR TEMPERATURE VS. RESISTANCE .

Test Description (Except Park Avenue)

The numbers below refer to the step numbers in the diagnostic procedures.

1. 3 This step tests for excessive resistance in the ECT sensor circuit.
2. 4 This step tests for excessive resistance in the IAT sensor circuit.
3. 8 This step tests for a skewed sensor through the range of temperatures that is affecting this DTC.

Diagnostic Procedures (Except Park Avenue)

SENSOR TEMPERATURE VS. RESISTANCE

Scheme 269

Scheme 270

Scheme 271

Scheme 272

Scheme 273

DTC P0117: ECT SENSOR CIRCUIT - LOW VOLTAGE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

The Engine Coolant Temperature (ECT) sensor is a variable resistor, that measures the temperature of the engine coolant. The Powertrain Control Module (PCM) supplies 5 volts to the ECT signal circuit and a ground for the ECT low reference circuit. When the ECT is cold, the sensor resistance is high. When the ECT increases, the sensor resistance decreases. With high sensor resistance, the PCM detects a high voltage on the ECT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the ECT signal circuit. If the PCM detects an excessively low ECT signal voltage, which is a high temperature indication, DTC P0117 sets.

1. Engine is running for more than 15 seconds.

The PCM detects that the ECT sensor parameter is more than 282°F (139°C) for more than 10 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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 overheating condition may cause this DTC to set. After starting engine, ECT sensor temperature should rise steadily to about 194°F (90°C) then stabilize after thermostat opens.

A skewed sensor could result in poor driveability concerns.

For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM.

Scheme 274

DTC P0118: ECT SENSOR CIRCUIT - HIGH VOLTAGE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

The Engine Coolant Temperature (ECT) sensor is a variable resistor, that measures the temperature of the engine coolant. The ECT sensor has a signal circuit and a low reference circuit. The Powertrain Control Module (PCM) supplies 5 volts to the ECT signal circuit and a ground for the ECT low reference circuit. When the ECT is cold, the sensor resistance is high. When the ECT increases, the sensor resistance decreases. With high sensor resistance, the PCM detects a high voltage on the ECT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the ECT signal circuit. If the PCM detects an excessively high ECT signal voltage, which is a low temperature indication, DTC P0118 sets.

Engine is running for more than 15 seconds.

The PCM detects that the ECT sensor parameter is less than -36°F (-38°C) for more than 24 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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.

If a short to a separate voltage source occurs this DTC may set and damage the ECT sensor.

After starting engine, ECT should rise steadily to about 194°F (90°C), then stabilize after thermostat opens.

Check for skewed ECT sensor. See SENSOR TEMPERATURE VS. RESISTANCE .

For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM.

Scheme 275

Scheme 276

DTC P0121: TP SENSOR PERFORMANCE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

the throttle position (TP) sensor is used by the Powertrain Control Module (PCM) to determine the throttle plate angle for various engine management systems. The TP sensor is a potentiometer type sensor with a 5-volt reference circuit, a low reference circuit and a signal circuit.

The PCM provides the TP sensor with 5 volts on the 5-volt reference circuit. Rotation of the TP sensor rotor from the closed throttle position to the Wide-Open Throttle (WOT) position provides the PCM with a signal voltage from less than 1 volt to more than 4 volts through the TP sensor signal circuit. When the conditions for running the DTC are met, the PCM will use the Manifold Absolute Pressure (MAP) sensor to determine if the predicted operating range of the TP sensor is correct. If the PCM detects that the TP sensor voltage is out of the predicted range DTC P0121 sets.

1. DTCs P0107, P0108, P0122, or P0123 are not set.
2. Engine is running for more than 2 minutes.
3. ECT is more than 167°F (75°C).
4. The Manifold Absolute Pressure (MAP) is less than 50 kPa for a TP sensor skewed high test.
5. The MAP is more than 70 kPa for a TP sensor skewed low test.
6. The MAP is steady for 5 seconds or more.

1. The TP sensor voltage is more than a predicted value when the MAP is below 50 kPa.
2. The TP sensor voltage is less than a predicted value when the MAP is above 70 kPa.
3. Conditions are met for 10 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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.

Note. If any other DTCs are set, diagnose those DTCs first.

Scheme 277

Scheme 278

Scheme 279

DTC P0122: TP SENSOR CIRCUIT - LOW VOLTAGE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Throttle Position (TP) sensor is used by Powertrain Control Module (PCM) to determine throttle plate angle for various engine management systems. TP sensor is a potentiometer type sensor with 3 circuits, a 5-volt reference circuit, a low reference circuit, and a signal circuit. PCM provides TP sensor with a 5-volt reference circuit and a low reference circuit. Rotation of TP sensor rotor from closed throttle position to Wide-Open Throttle (WOT) position provides PCM with a signal voltage from less than one volt to more than 4.0 volts through TP sensor signal circuit. DTC sets when PCM detects an excessively low signal voltage.

Ignition is on.

The PCM detects that the TP sensor signal voltage is less than 0.1 volt for more than 1 second.

1. The control module illuminates the Malfunction Indicator Light (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 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 in the diagnostic procedures.

1. 5 This step determines if the 5-volts supplied by the PCM is available to the sensor. It also determines if there is sufficient current flow in the circuit.

Scheme 280

Scheme 281

DTC P0123: TP SENSOR CIRCUIT - HIGH VOLTAGE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Throttle Position (TP) sensor is used by Powertrain Control Module (PCM) to determine throttle plate angle for various engine management systems. TP sensor is a potentiometer type sensor with 3 circuits, a 5-volt reference circuit, a low reference circuit, and a signal circuit. PCM provides TP sensor with a 5-volt reference circuit and a low reference circuit. Rotation of TP sensor rotor from closed throttle position to Wide-Open Throttle (WOT) position provides PCM with a signal voltage from less than one volt to more than 4 volts through TP sensor signal circuit. DTC sets when PCM detects an excessively high signal voltage.

Ignition is ON.

The PCM that the TP sensor signal voltage is more than 4.9 volts for more than 1 second.

1. The control module illuminates the Malfunction Indicator Light (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 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.

Scheme 282

Scheme 283

DTC P0125: ECT EXCESSIVE TIME TO ENTER CLOSED LOOP FUEL CONTROL

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

An Engine Coolant Temperature (ECT) sensor monitors the temperature of the coolant. This input is used by the Powertrain Control Module (PCM) for engine control and as an enabling criteria for some diagnostics. The airflow coming into the engine is accumulated and used to determine if the engine has been driven within conditions that would allow the engine coolant to heat up normally to the thermostat regulating temperature. If the coolant temperature does not increase normally or does not reach regulating temperature of the thermostat, diagnostics that use engine coolant temperature as enabling criteria, may not run when expected. This DTC will only run once per ignition cycle within the enabling conditions. This DTC will set when there has been excessive time to reach a minimum coolant temperature required for closed loop fuel control.

1. DTCs P0101, P0102, P0103, P0112, P0113, P0116, P0117, P0118, P0502, P0503 are not set.
2. The minimum air temperature is more than 19°F (-7°C).
3. The start-up Engine Coolant Temperature (ECT) is more than -38°F (-39°C), but less than the Closed Loop temperature of 14°F (-10°C).
4. The engine run time is 200-1500 seconds.
5. The vehicle has traveled more than 0.5 miles at more than 15 MPH.
6. The average MAF is more than 5 g/s.

1. The calibrated amount of air flow has been met.
2. The calibrated amount of engine run time has been met.
3. The minimum ECT for Closed Loop of 14°F (10°C) has not been met.

1. The control module illuminates the Malfunction Indicator Light (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 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.

DTC P0125 is designed to detect a skewed ECT sensor.

If a DTC P0125 and a P0128 are set a faulty thermostat may be the cause, M/T.

The numbers below refer to the step numbers in the diagnostic procedures.

1. 3 This step tests for excessive resistance in the ECT circuit.
2. 7 This step tests for a skewed sensor through the range of temperatures affecting this DTC.

Scheme 284

DTC P0128: ECT LESS THAN THERMOSTAT REGULATING TEMPERATURE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

An Engine Coolant Temperature (ECT) sensor monitors the temperature of the coolant. This input is used by the Powertrain Control Module (PCM) for engine control and as an enabling criteria for some diagnostics.

The air flow coming into the engine is accumulated and used to determine if the vehicle has been driven within the conditions that would allow the engine coolant to heat up normally to the thermostat regulating temperature. If the coolant temperature does not increase normally or does not reach the regulating temperature of the thermostat, diagnostics that use ECT as enabling criteria may not run when expected.

This DTC will only run once per ignition cycle within the enabling condition. If the PCM detects the calibrated amount of air flow and engine run time have been met, and the ECT has not met the minimum thermostat regulating temperature, DTC P0128 sets.

1. Coolant temperature is more than -38°F (-39°C).
2. Air temperature is more than 19°F (-7°C).
3. Engine has run more than 4 minutes.
4. VSS average is more than 15 MPH over key cycle.
5. Mass Airflow (MAF) average reading is more than 20 grams/second.
6. Vehicle has been driven more than 3 miles.
7. DTCs P0101, P0102, P0103, P0112, P0113, P0116, P0117, P0118, P0125, P0502, P0503, P1114, or P1115 are not set.

The PCM detects that

1. The calibrated amount of engine run time has been met.
2. The calibrated amount of engine air flow has been met.
3. The calibrated ECT of 176°F (80°C) had not been met.

1. The control module illuminates the Malfunction Indicator Light (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 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. DTC P0128 is designed to detect a faulty thermostat.
2. It is possible for a skewed low ECT sensor to cause DTC P0128 to set.

The numbers below refer to the step numbers in the diagnostic procedures.

1. 3 This step tests for excessive resistance in the ECT circuit.
2. 7 This step tests for a skewed sensor through the range of temperatures affecting this DTC.

Scheme 285

Scheme 286

Scheme 287

DTC P0130: HO2S LOW ACTIVITY - SENSOR 1

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Heated Oxygen Sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the vehicle is first started, the Powertrain Control Module (PCM) operates in an Open Loop mode, ignoring the HO2S signal voltage when calculating the air-to-fuel ratio. The PCM supplies the HO2S with a reference or bias voltage of about 450 mV. The HO2S generates a voltage within a range of 0-1000 mV that fluctuates above and below bias voltage once in Closed Loop. A high HO2S voltage output indicates a rich fuel mixture. A low HO2S voltage output indicates a lean mixture. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature, and provide an accurate voltage signal. If the PCM detects an active HO2S 1 signal of a lower than calibrated minimum amplitude, DTC P0130 will set.

Each HO2S has the following circuits

1. HO2S 1 high signal.
2. HO2S 1 low signal.
3. HO2S 1 heater ignition 1 voltage.
4. HO2S 1 heater ground.

1. DTCs P0101, P0102, P0103, P0107, P0108, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0410, P0440, P0442, P0443, P0446, P0449, P1133, P1134 or P1441 are not set.
2. The Engine Run Time parameter is at least 4 minutes.
3. The MAF sensor parameter is 10-35 g/s.
4. The Engine Speed parameter is 550-3000 RPM.
5. The TP sensor parameter is 5-35 percent.
6. The ECT sensor parameter is more than 158°F (70°C).
7. The system voltage is 9-18 volts.

The PCM detects an active sensor with an improper voltage signal amplitude.

1. The control module illuminates the Malfunction Indicator Light (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 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 in the diagnostic procedures.

1. 2 A normally functioning HO2S 1 voltage signal will fluctuate above and below the bias voltage amount.
2. 4 The voltage reading must change from the bias amount to below the specified amount when the signal circuits are jumped to a good ground. This step checks the continuity of the signal circuits.
3. 6 This step verifies that there are functional HO2S 1 heater power and ground circuits.
4. 8 The conditions listed in the table may contribute to the failure of the HO2S. The conditions listed apply only to this type of failure.

Scheme 288

Scheme 289

DTC P0131: HO2S CIRCUIT LOW VOLTAGE - SENSOR 1

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Heated Oxygen Sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the vehicle is first started, the Powertrain Control Module (PCM) operates in an open loop mode, ignoring the HO2S signal voltage when calculating the air/fuel ratio. The PCM supplies the HO2S with a reference or bias voltage of about 450 millivolts. The HO2S generates a voltage within a range of 0-1000 millivolts that fluctuates above and below bias voltage once in closed loop. A high HO2S voltage output indicates a rich fuel mixture. A low HO2S voltage output indicates a lean mixture. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature, and provide an accurate voltage signal. This DTC will set if the HO2S 1 voltage remains below a calibrated amount for an excessive amount of time. Each HO2S has the following circuits

1. HO2S 1 high signal.
2. HO2S 1 low signal.
3. HO2S 1 heater ignition 1 voltage.
4. HO2S 1 heater ground.

1. System voltage is 9-18 volts.
2. System is in Closed Loop.
3. TP angle is 5-40 percent.
4. DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0410, P0440, P0442, P0443, P0446, P0449, or P1441 are not set.

The PCM detects that the HO2S 1 voltage is less than 175 mV, for more than 55 seconds.

The PCM detects that the HO2S 1 voltage is less than 600 mV, during Power Enrichment (PE) mode, for more than 55 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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 in the diagnostic procedures.

1. 2 A normally functioning HO2S 1 voltage signal will fluctuate above and below the bias voltage amount.
2. 5 A voltage reading other than bias voltage in this step indicates a short circuit in the high signal circuit.
3. 7 The conditions listed in the table may contribute to the failure of the HO2S. The conditions listed apply only to this type of failure.

Scheme 290

Scheme 291

DTC P0132: HO2S CIRCUIT HIGH VOLTAGE - SENSOR 1

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Heated Oxygen Sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the vehicle is first started, the Powertrain Control Module (PCM) operates in an open loop mode, ignoring the HO2S signal voltage when calculating the air/fuel ratio. The PCM supplies the HO2S with a reference or bias voltage of about 450 millivolts. The HO2S generates a voltage within a range of 0-1000 millivolts that fluctuates above and below bias voltage once in closed loop. A high HO2S voltage output indicates a rich fuel mixture. A low HO2S voltage output indicates a lean mixture. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature, and provide an accurate voltage signal. This DTC will set if the HO2S 1 voltage remains above a calibrated amount for an excessive amount of time. Each HO2S has the following circuits

1. HO2S 1 high signal.
2. HO2S 1 low signal.
3. HO2S 1 heater ignition 1 voltage.
4. HO2S 1 heater ground.

1. System voltage is 9-18 volts.
2. TP angle is 3-40 percent.
3. DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0410, P0440, P0442, P0443, P0446, P0449, or P1441 are not set.

The PCM detects that the HO2S 1 voltage is more than 976 mV in closed loop for more than 55 seconds.

The PCM detects that the HO2S 1 voltage is more than 200 mV in Decel Fuel Cut-Off (DFCO) for more than 32 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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 in the diagnostic procedures.

1. 2 A normally functioning HO2S 1 voltage signal will fluctuate above and below the bias voltage amount.
2. 4 A voltage reading other than bias voltage in this step indicates a short circuit condition in the high signal circuit.
3. 9 The conditions listed in the table may contribute to the failure of the HO2S. The conditions listed apply only to this type of failure.

Scheme 292

Scheme 293

DTC P0133: HO2S SLOW RESPONSE - SENSOR 1

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Heated Oxygen Sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the vehicle is first started the Powertrain Control Module (PCM) operates in an open loop mode, ignoring the HO2S signal voltage when calculating the air/fuel ratio. The PCM supplies the HO2S with a reference or bias voltage of about 450 millivolts. The HO2S generates a voltage within a range of 0-1000 millivolts that fluctuates above and below bias voltage once in closed loop. A high HO2S voltage output indicates a rich fuel mixture. A low HO2S voltage output indicates a lean mixture. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature, and provide an accurate voltage signal. The PCM monitors the HO2S rich-to-lean and lean-to-rich transition time. This DTC will set if the HO2S voltage average response time is too slow. Each HO2S has the following circuits

1. HO2S 1 high signal.
2. HO2S 1 low signal.
3. HO2S 1 heater ignition 1 voltage.
4. HO2S 1 heater ground.

1. DTCs P0101, P0102, P0103, P0107, P0108, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0410, P0440, P0442, P0443, P0446, P0449, P1133, P1134 or P1441 are not set.
2. The vehicle is not in Park or Neutral.
3. The Engine Run Time parameter is at least 60 seconds.
4. The Loop Status parameter is closed.
5. The MAF sensor parameter is 13-30 g/s.
6. The Engine Speed parameter is 1000-3000 RPM.
7. The ECT Sensor parameter is more than 122°F (50°C).
8. The system voltage is 9-18 volts.

The PCM detects that the HO2S 1 rich-to-lean transition time takes longer than 145 milliseconds.

The PCM detects that the HO2S 1 lean-to-rich transition time takes longer than 135 milliseconds.

1. The control module illuminates the Malfunction Indicator Light (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 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 in the diagnostic procedures.

1. 2 A normally functioning HO2S 1 voltage signal will fluctuate above and below the bias voltage amount.
2. 4 The voltage reading must change from the bias amount to below the specified amount when the signal circuits are jumped to a good ground. This step checks the continuity of the signal circuits.
3. 6 This step verifies that there are functional HO2S 1 heater power and ground circuits.
4. 8 The conditions listed in the table may contribute to the failure of the HO2S. The conditions listed apply only to this type of failure.

Note. If any other DTCs are set, except HO2S DTCs, diagnose other DTCs first before proceeding with this procedure.

Scheme 294

Scheme 295

DTC P0134: HO2S CIRCUIT INSUFFICIENT ACTIVITY - SENSOR 1

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Heated Oxygen Sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the vehicle is first started, the Powertrain Control Module (PCM) operates in an open loop mode, ignoring the HO2S signal voltage when calculating the air/fuel ratio. The PCM supplies the HO2S with a reference or bias voltage of about 450 millivolts. The HO2S generates a voltage within a range of 0-1000 millivolts that fluctuates above and below bias voltage once in closed loop. A high HO2S voltage output indicates a rich fuel mixture. A low HO2S voltage output indicates a lean mixture. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature, and provide an accurate voltage signal. This DTC will set if the HO2S 1 voltage remains at or near the bias voltage amount. Each HO2S has the following circuits

1. HO2S 1 high signal.
2. HO2S 1 low signal.
3. HO2S 1 heater ignition 1 voltage.
4. HO2S 1 heater ground.

1. The system voltage is 9-18 volts.
2. Engine run time is longer than 200 seconds.
3. DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0410, P0440, P0442, P0443, P0446, P0449, or P1441 are not set.

The PCM detects that the HO2S 1 signal voltage remains between 400-500 mV for more than 30 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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 in the diagnostic procedures.

1. 2 A normally functioning HO2S 1 voltage signal will fluctuate above and below the bias voltage amount.
2. 4 The voltage reading must change from the bias amount to below the specified amount when the signal circuits are jumped to a good ground. This step checks the continuity of the signal circuits.
3. 6 This step verifies that there are functional HO2S 1 heater power and ground circuits.
4. 7 The conditions listed in the table may contribute to the failure of the HO2S. The conditions listed apply only to this type of failure.

Scheme 296

Scheme 297

DTC P0135: HO2S HEATER PERFORMANCE - SENSOR 1

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Heated Oxygen Sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the vehicle is first started, the Powertrain Control Module (PCM) operates in an Open Loop mode, ignoring the HO2S signal voltage when calculating the air-to-fuel ratio. The PCM supplies the HO2S with a reference or bias voltage of about 450 mV. The HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage once in Closed Loop. A high HO2S voltage output indicates a rich fuel mixture. A low HO2S voltage output indicates a lean mixture. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature, and provide an accurate voltage signal. The HO2S 1 heater performance diagnostic will only run from a cold start and only once per key cycle. This DTC will set if the HO2S 1 heater takes too long to heat based on the HO2S 1 signal voltage input to the PCM. The HO2S 1 heater circuit is energized anytime the ignition key is in the ON position. If the PCM detects that the HO2S 1 heater takes too long to heat, based on the HO2S 1 signal voltage, DTC P0135 will set. The HO2S 1 has the following circuits

1. HO2S 1 high signal.
2. HO2S 1 low signal.
3. HO2S 1 heater ignition 1 voltage.
4. HO2S 1 heater ground.

1. DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0410, P0440, P0442, P0443, P0446, P0449, or P1441 are not set.
2. The Intake Air Temperature (IAT) and the Engine Coolant Temperature (ECT) are within 11°F (6°C) of each other at start-up.
3. The HO2S 1 parameter must be between 400-500 mV at start-up.
4. The system voltage is 9-18 volts.

The PCM detects that the HO2S 1 voltage remains within 150 mV of the bias voltage, about 450 mV, for a longer amount of time than necessary. The amount of time ranges between 50-80 seconds depending on ECT at start up and average MAF since start up.

1. The control module illuminates the Malfunction Indicator Light (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 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 in the diagnostic procedures.

1. 2 The HO2S 1 should be allowed to cool before performing this test. The HO2S 1 is cool enough if the voltage output is stable at bias or, about 450 millivolts. If the HO2S 1 heater is functioning, the signal voltage will gradually decrease as the sensor element warms. If the heater is not functioning, the HO2S 1 signal will remain near the 450 millivolts bias voltage.
2. 4 This step ensures that the ignition 1 voltage circuit to the HO2S 1 is not open or shorted. The test light must be connected to a good ground, independent of the HO2S system.
3. 6 This test must not be performed until the HO2S 1 heater has cooled and stabilized for at least 15 minutes. Heater resistance is typically about 5 ohms at room temperature.

Scheme 298

Scheme 299

DTC P0137: HO2S CIRCUIT LOW VOLTAGE - SENSOR 2

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the vehicle is first started, the (PCM) operates in an Open Loop mode, ignoring the HO2S signal voltage when calculating the air-to-fuel ratio. The PCM supplies the HO2S with a reference or bias voltage of about 450 mV. The HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage once in Closed Loop. A high HO2S voltage output indicates a rich fuel mixture. A low HO2S voltage output indicates a lean mixture. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature and provide an accurate voltage signal. The HO2S 2 is used for post catalyst monitoring. If the PCM detects that the HO2S 2 voltage remains below a calibrated amount for an excessive amount of time, DTC P0137 will set. The HO2S 2 has the following circuits

1. HO2S 2 high signal.
2. HO2S 2 low signal.
3. HO2S 2 heater ignition 1 voltage.
4. HO2S 2 heater ground.

1. Ignition voltage is 9-18 volts.
2. System is in Closed Loop.
3. The TP angle is 5-40 percent.
4. DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0410, P0440, P0442, P0443, P0446, P0449, or P1441 are not set.

The PCM detects that the HO2S 2 signal voltage remains below 61 mV during Closed Loop operation, for more than 2 minutes.

The PCM detects that the HO2S 2 signal voltage remains below 550 mV during Power Enrichment (PE) mode and the Air Fuel Ration parameter is below 12.5:1 for more than 25 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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 in the diagnostic procedures.

1. 2 A normally functioning HO2S 2 voltage signal will fluctuate above and below the bias voltage amount. The action in the test step should result in a visible reaction from the HO2 S 2 output.
2. 5 A voltage reading other than bias voltage in this step indicates a short circuit condition in the high signal circuit.
3. 7 The conditions listed in the table may contribute to the failure of the HO2S. The conditions listed apply only to this type of failure.

Scheme 300

Scheme 301

DTC P0138: HO2S CIRCUIT HIGH VOLTAGE - SENSOR 2

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Heated Oxygen Sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the vehicle is first started, the Powertrain Control Module (PCM) operates in an open loop mode, ignoring the HO2S signal voltage when calculating the air/fuel ratio. The PCM supplies the HO2S with a reference or bias voltage of about 450 millivolts. The HO2S generates a voltage within a range of 0-1000 millivolts that fluctuates above and below bias voltage once in closed loop. A high HO2S voltage output indicates a rich fuel mixture. A low HO2S voltage output indicates a lean mixture. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature, and to provide an accurate voltage signal. The HO2S 2 is used for post catalyst monitoring. This DTC will set if the HO2S 2 voltage remains above a calibrated amount for an excessive amount of time. Each HO2S 2 has the following circuits

1. HO2S 2 high signal.
2. HO2S 2 low signal.
3. HO2S 2 heater ignition 1 voltage.
4. HO2S 2 heater ground.

1. DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0410, P0440, P0442, P0443, P0446, P0449, or P1441 are not set.
2. The Air Fuel Ratio parameter is 14.5:1-14.8:1.
3. The TP sensor parameter is 3-40 percent.
4. The system voltage is 9-18 volts.

The PCM detects that the HO2S 2 voltage is more than 975 mV for more than 75 seconds during Closed Loop operation.

The PCM detects that the HO2S 2 voltage is more than 200 mV, during Decel Fuel Cut-Off (DFCO), for more than 100 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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 in the diagnostic procedures.

1. 2 A normally functioning HO2S 2 voltage signal will fluctuate above and below the bias voltage amount. The action in the test step should result in a visible reaction from the HO2S 2 output.
2. 4 A voltage reading other than bias voltage in this step indicates a short circuit condition in the high signal circuit.
3. 6 The conditions listed in the table may contribute to the failure of the HO2S. The conditions listed apply only to this type of failure.

Scheme 302

Scheme 303

DTC P0140: HO2S CIRCUIT INSUFFICIENT ACTIVITY - SENSOR 2

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Heated Oxygen Sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the vehicle is first started the Powertrain Control Module (PCM) operates in an Open Loop mode, ignoring the HO2S signal voltage when calculating the air-to-fuel ratio. The PCM supplies the HO2S with a reference or bias voltage of about 450 mV. The HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage once in Closed Loop. High HO2S voltage output indicates a rich fuel mixture; low HO2S voltage output indicates a lean mixture. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature, and provide an accurate voltage signal. The HO2S 2 is used for post catalyst monitoring. If the PCM detects that the HO2S 2 voltage remains at or near the bias voltage amount, DTC P0140 will set Each HO2S 2 has the following circuits

1. HO2S 2 high signal.
2. HO2S 2 low signal.
3. HO2S 2 heater ignition 1 voltage.
4. HO2S 2 heater ground.

1. DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0410, P0440, P0442, P0443, P0446, P0449, and P1441 are not set.
2. The engine run time is longer than 200 seconds.

The PCM detects that the HO2S 2 signal voltage remains between 412-490 mV for more than 90 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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 in the diagnostic procedures.

1. 2 A normally functioning HO2S 2 voltage signal will fluctuate above and below the bias voltage amount. The action in the test step should result in a visible reaction from the HO2S 2 output.
2. 4 A voltage reading other than the specified amount in this step indicates an open circuit condition in one of the signal circuits or the PCM.
3. 5 This step inspects for an open circuit condition in the signal circuits, independent of the PCM.
4. 7 The conditions listed in the table may contribute to the failure of the HO2S. The conditions listed apply only to this type of failure.

Scheme 304

Scheme 305

DTC P0141: HO2S 2 HEATER PERFORMANCE - SENSOR 2

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Heated Oxygen Sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the vehicle is first started the Powertrain Control Module (PCM) operates in an open loop mode, ignoring the HO2S signal voltage when calculating the air/fuel ratio. The PCM supplies the HO2S with a reference or bias voltage of about 450 millivolts. The HO2S generates a voltage within a range of 0-1000 millivolts that fluctuates above and below bias voltage once in closed loop. High HO2S voltage output indicates a rich fuel mixture. Low HO2S voltage output indicates a lean mixture. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature, and provide an accurate voltage signal. The HO2S 2 heater performance diagnostic will only run from a cold start and only once per key cycle. This DTC will set if the HO2S 2 heater takes too long to heat based on the HO2S 2 signal voltage input to the PCM. The HO2S 2 heater circuit is energized anytime the ignition key is in the ON position. The HO2S 2 has the following circuits

1. HO2S 2 high signal.
2. HO2S 2 low signal.
3. HO2S 2 heater ignition 1 voltage.
4. HO2S 2 heater ground.

1. DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0410, P0440, P0442, P0443, P0446, P0449, and P1441 are not set.
2. IAT and ECT are within 11°F (6°C) of each other at start-up.
3. The HO2S 1 parameter must be between 400-500 mV at start up.
4. System voltage is 9-18 volts.

The PCM detects that the HO2S 2 voltage remains within 100 mV of the bias voltage, about 450 mV, for a longer amount of time than necessary. The amount of time ranges between 50-80 seconds depending on ECT at start up, and the average Mass Airflow (MAF) since start up.

1. The control module illuminates the Malfunction Indicator Light (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 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 in the diagnostic procedures.

1. 2 The HO2S 2 should be allowed to cool before performing this test. The HO2S 2 is cool enough if the voltage output is stable at bias or about 450 millivolts. If the HO2S 2 heater is functioning, the signal voltage will gradually decrease as the sensor element warms. If the heater is not functioning, the HO2S 2 signal will remain near the 450 millivolts bias voltage.
2. 4 This step ensures that the ignition 1 voltage circuit to the HO2S 2 is not open or shorted. The test light must be connected to a good ground, independent of the HO2S system.
3. 6 This test must not be performed until the HO2S 2 heater has cooled and stabilized for at least 15 minutes. Heater resistance is typically about 5 ohms at room temperature.

Scheme 306

Scheme 307

DTC P0171: FUEL TRIM SYSTEM LEAN

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Powertrain Control Module (PCM) controls air/fuel metering system in order to provide best possible combination of driveability, fuel economy and emission control. Fuel delivery is controlled differently during open and closed loop. During open loop, PCM determines fuel delivery based on sensor signals, without oxygen sensor input. During closed loop PCM adds oxygen sensor inputs to calculate short and long term fuel trim (fuel delivery adjustments). If oxygen sensors indicate a lean condition, fuel trim values will be more than zero percent. If oxygen sensors indicate a rich condition, fuel trim values will be less than zero percent. Short Term Fuel Trim (STFT) values change rapidly in response to Heated Oxygen Sensor (HO2S) voltage signals. Long Term Fuel Trim (LTFT) makes coarse adjustments in order to maintain an air/fuel ratio of 14.7:1. DTC sets when PCM detects an excessively lean condition.

1. DTCs P0101, P0102, P0103, P0107, P0108, P0121, P0122, P0123, P0130, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0201, P0202, P0203, P0204, P0205, P0206, P0300, P0401, P0403, P0404, P0405, P0410, P0440, P0442, P0446, P0506, P0507, P1404, or P1441 are not set.
2. Engine Coolant Temperature (ECT) is 68-230°F (20-110°C).
3. Intake Air Temperature (IAT) is 64-158°F (18-70°C).
4. Manifold Absolute Pressure (MAP) is 15-105 kPa.
5. Vehicle speed is less than 82 MPH.
6. Engine speed is 600-4000 RPM.
7. Barometric (BARO) pressure is more than 70 kPa.
8. Mass Airflow (MAF) is 5-150 grams/second.
9. Fuel level is more than 10 percent.

1. The value average of the Long Term fuel trim is above 20 percent.
2. All of C conditions are present for 6 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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 in the diagnostic procedures.

1. 5 Refer to fuel system diagnostics for a possible fuel condition if conditions were not corrected. See «FUEL SYSTEMS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l__fuel-systems) in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
2. 6 If conditions were not corrected, a worn cam, worn intake, exhaust values or other engine mechanical failures may be at fault.

System will go lean if an injector is not suppling enough fuel. A lean condition could be present during high fuel demand due to a fuel pump that does not pump enough fuel.

Using a scan tool, review the Failure Records. If an intermittent condition is suspected, see INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM.

Note. If any DTCs are set, other than P0171, diagnose those DTCs before continuing. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .

Scheme 308

Scheme 309

DTC P0172: FUEL TRIM SYSTEM RICH

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Powertrain Control Module (PCM) controls air/fuel metering system in order to provide best possible combination of driveability, fuel economy and emission control. Fuel delivery is controlled differently during open and closed loop. During open loop, PCM determines fuel delivery based on sensor signals, without oxygen sensor input. During closed loop, oxygen sensor inputs are added and used by PCM to calculate short and long term fuel trim fuel delivery adjustments. If oxygen sensors indicate a lean condition, fuel trim values will be more than zero percent. If oxygen sensors indicate a rich condition, fuel trim values will be less than zero percent. Short term fuel trim values change rapidly in response to Heated Oxygen Sensor (HO2S) voltage signals. Long term fuel trim makes coarse adjustments in order to maintain air/fuel ratio of 14.7:1. Fuel trim diagnostic will conduct a test to determine if a rich failure actually exists or if excessive vapor from Evaporative (EVAP) emission canister is causing a rich condition. If PCM detects an excessively rich condition, this DTC will set. If PCM detects excessive vapor then a pass is logged.

1. DTCs P0101, P0102, P0103, P0107, P0108, P0121, P0122, P0123, P0130, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0201-P0206, P0300, P0401, P0403, P0404, P0405, P0410, P0412, P0418, P0440, P0442, P0446, P0506, P0507, P1404, or P1441 are not set.
2. Engine Coolant Temperature (ECT) is 68-239°F (20-110°C).
3. Intake Air Temperature (IAT) is 64-158°F (18-70°C).
4. Manifold Absolute Pressure (MAP) is 15-105 kPa.
5. Vehicle speed is less than 82 MPH.
6. Engine speed is 600-4000 RPM.
7. Barometric (BARO) pressure is more than 70 kPa.
8. Mass Airflow (MAF) is 5-150 grams/second.
9. Fuel level is more than 10 percent.

DTC sets when average long term fuel trim value is less than -13 percent for more than 40 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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.

Fuel contamination, such as water and alcohol, will affect fuel trim.

A malfunctioning MAF sensor can cause a rich condition and set this DTC. See DTC P0101: MAF SYSTEM PERFORMANCE .

Using a scan tool, review the Failure Records. If an intermittent condition is suspected, see INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM.

The numbers below refer to the step numbers in the diagnostic procedures.

1. 5 If conditions were not corrected, refer to fuel system diagnostic for possible fuel problem. See «FUEL SYSTEMS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l__fuel-systems) in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
2. 6 An EVAP canister that is saturated will cause a rich condition. Fuel in the vacuum line to the fuel pressure regulator indicates a leaking regulator. If conditions were not corrected, a worn cam, worn intake or exhaust valves or other engine mechanical failure may be at fault.

Note. If any DTCs are set, other than P0172, diagnose those DTCs before continuing. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .

Scheme 310

Scheme 311

DTC P0201-P0206: INJECTOR CONTROL CIRCUIT

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

The Powertrain Control Module (PCM) enables appropriate fuel injector on intake stroke for each cylinder. Ignition voltage is supplied to fuel injectors. The PCM controls each fuel injector by grounding control circuit via a solid state device called a driver. The PCM monitors status of each driver. If control module detects an incorrect voltage for commanded state of the driver, a fuel injector control DTC sets.

1. Engine is running.
2. Ignition voltage is 9-18 volts.

The PCM detects an incorrect voltage on the fuel injector control circuit. The condition exists for 30 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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.

Performing fuel injector coil test may help to isolate an intermittent condition. See SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.

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

The numbers below refer to the step numbers in the diagnostic procedures.

1. 4 This step tests for voltage at the fuel injector harness connector. The INJR fuse supplies power to the coil side of the fuel injector harness connector. If the fuse is open, a short to ground on the injection 1voltage supply circuit of the fuel injector is indicated.
2. 5 This step verifies that the PCM is able to control the fuel injector. If the test light blinks, then the PCM and wiring are okay.
3. 6 This step tests if a ground is constantly being applied to the fuel injector.

Scheme 312

Scheme 313

DTC P0230: FUEL PUMP CONTROL CIRCUIT

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Powertrain Control Module (PCM) provides ignition positive voltage to coil side of fuel pump relay. When ignition is first turned on, PCM energizes fuel pump relay, which applies power to fuel pump. PCM enables fuel pump relay as long as engine is cranking or running, and crankshaft reference pulses are received. If no crankshaft reference pulses are received, PCM de-energizes fuel pump relay after 2 seconds. PCM monitors voltage on fuel pump relay control circuit. DTC sets when PCM detects an incorrect voltage on fuel pump relay control circuit.

1. Ignition is on.
2. System voltage is 9-18 volts.

The PCM detects an incorrect voltage on the control circuit of the fuel pump relay. The condition exists for less than 1 second.

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

Conditions For Clearing DTC

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

The numbers below refer to the step numbers in the diagnostic procedures.

1. 2 Listen for an audible click when the fuel pump relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
2. 4 This step verifies that the PCM is providing voltage to the fuel pump relay.
3. 5 This step tests for an open in the ground circuit to the fuel pump relay.
4. 6 This step tests if voltage is constantly being applied to the control circuit of the fuel pump relay.

Scheme 314

Scheme 315

DTC P0243: SUPERCHARGER BOOST SOLENOID CONTROL CIRCUIT (VIN 1)

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Output Driver Modules (ODMs) are used by the Powertrain Control Module (PCM) to turn on many of the current-driven devices that are needed to control various engine and transaxle functions. Each ODM is capable of controlling up to 7 separate outputs by applying ground to the device which the PCM is commanding on. Unlike the Quad Driver Modules (QDMs) used in prior model years, ODMs have the capability of diagnosing each output circuit individually. DTC P0243 indicates an improper voltage level has been detected in the supercharger boost control solenoid control circuit.

Ignition is on.

An improper voltage level has been detected on the boost control solenoid control circuit. The conditions are met for at least 30 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Light (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 emission related diagnostic.
3. Clear DTC with a scan tool.

Check for the following conditions

1. Poor connection at the PCM or the boost control solenoid. Inspect harness connectors for: Backed out terminals. Improper mating. Broken locks. Improperly formed or damaged terminals. Poor terminal to wire connection.
2. Damaged harness. Inspect the wiring harness for damage.
3. If the harness appears to be okay, disconnect the PCM, turn on the ignition and observe a voltmeter connected between the boost control solenoid control circuit and ground at the PCM harness connector while moving connectors and wiring harnesses related to the boost control solenoid. A change in voltage will indicate the location of the malfunction.

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.

The numbers below refer to the step numbers in the diagnostic procedures.

1. 3 This test can detect a partially shorted coil which would cause excessive current flow. Leaving the circuit energized for 2 minutes allows the coil to warm up. When warm, the coil may open, amps drops to 0, or short, amps goes above 800 mA.
2. 4 Tests for a short to voltage on the control circuit.

Scheme 316

Scheme 317

DTC P0300: ENGINE MISFIRE DETECTED

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Powertrain Control Module (PCM) uses information from Ignition Control (IC) module and Camshaft Position (CMP) sensor in order to determine when an engine misfire is occurring. By monitoring variations in crankshaft rotation speed for each cylinder, PCM is able to detect individual misfire events. A misfire rate that is high enough can cause 3-way catalytic converter to overheat under certain conditions. Malfunction Indicator Light (MIL) will flash on and off when conditions for 3-way catalytic converter overheating are present. If the PCM detects a misfire rate sufficient to cause emission levels to exceed mandated standards, DTC P0300 will set.

1. DTCs P0101, P0102, P0103, P0107, P0108, P0016, P0117, P0118, P0121, P0122, P0123, P0125, P0336, P033, P0341, P0502, P0503, P1106, P1107, P1114, P1115, P1121, P1122, P1336, P1351, P1352, P1361, P1362 or P1374 are not set.
2. Engine speed is 475-5850 RPM.
3. System voltage is 9-18 volts.
4. ECT is 21-257°F (-7-125°C).
5. The fuel level is more than 10 percent.
6. The Anti-Lock Brake System (ABS) and the Traction Control System (TCS) are not active.
7. The transmission is not changing starts.
8. The A/C clutch is not changing states.
9. The PCM is not in fuel shut off or decel fuel cut-off mode.
10. The PCM is not receiving a rough road signal.

The PCM is detecting a crankshaft rotation speed variation indicating a misfire sufficient to cause emission levels to exceed mandated standards.

1. The control module illuminates the Malfunction Indicator Light (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 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.

Note. If level of misfire was sufficient to cause possible catalyst damage (if MIL was flashing), ensure that DTC P0420 test has been completed and passed after verifying misfire repair. See DTC P0420: CATALYST SYSTEM LOW EFFICIENCY .

1. Excessive vibration from sources other than the engine could cause DTC P0300 to set. The following are possible sources Variable thickness brake rotors. Worn or damage accessory drive belt. See ENGINE MECHANICAL in TROUBLE SHOOTING - BASIC PROCEDURES article in GENERAL INFORMATION.
2. Spray water on the secondary ignition components using spray bottle. Look and lister for arcing or misfiring.

The numbers below refer to the step numbers in the diagnostic procedures.

1. 2 If the actual CKP variation values are not within the learned values, the misfire counters may increment.

Scheme 318

Scheme 319

Scheme 320

DTC P0325: KNOCK SENSOR MODULE CIRCUIT

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

The Knock Sensor (KS) produces an AC voltage at all engine speeds and loads. Depending on the amplitude and frequency of the KS signal, the Powertrain Control Module (PCM) will adjust the spark timing. The PCM uses the KS signal in order to calculate the average voltage. The PCM inspects the KS and the related wiring by comparing the actual knock signal to the assigned voltage range. If the KS system is operating correctly, the PCM should monitor the KS voltage that is varying above and below a predetermined average voltage. This DTC will set if the PCM malfunctions in a manner that will not allow proper diagnosis of the KS system.

1. DTCs P0101, P0102, P0103, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0336, P0341, P0502, P0503, P1114, P1115, P1121, or P1336 are not set.
2. Engine speed is 1000-2500 RPM.
3. Throttle angle is more than 10 percent.
4. Engine load is more than 40 percent.
5. Engine Coolant Temperature (ECT) is more than 140°F (60°C).
6. Maximum spark retard is less than 15 degrees.
7. System voltage is more than 9 volts.
8. Engine run time is more than 30 seconds.

The PCM detects a malfunction in the Knock Sensor (KS) diagnostic circuitry which will not allow proper diagnosis of the KS circuit.

1. The control module illuminates the Malfunction Indicator Light (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 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.

Scheme 321

DTC P0327 & P0332: KNOCK SENSOR CIRCUIT BANK 1 & 2

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

The Knock Sensor (KS) diagnostic circuitry is contained within the Powertrain Control Module (PCM). The KS produces an AC voltage at all engine speeds and at loads. The PCM adjusts spark timing that is based on the amplitude and on the frequency of the KS signal. The PCM uses the KS signal in order to calculate the average voltage. Then the PCM assigns a voltage value. The PCM inspects the KS and related wiring by comparing the actual knock signal to the assigned voltage range. A normal KS signal should stay outside the assigned voltage range. This DTC will set if the KS signal is within the assigned voltage range, or if the KS signal is not present. DTC P0327 refers to the bank 1 KS and DTC P0332 refers to bank 2 KS.

1. DTCs P0101, P0102, P0103, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0336, P0341, P0502, P0503, P1114, P1115, P1121, P1122, P1336 are not set.
2. Engine speed is 1000-2500 RPM.
3. Engine run time is more than 30 seconds.
4. TP angle more than 10 percent.
5. Engine load is more than 40 percent.
6. ECT more than 140°F (60°C).
7. Maximum spark retard less than 15 degrees.
8. System voltage more than 9 volts.

The PCM detects a KS signal voltage within the predetermined average voltage range for at least 10 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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 in the diagnostic procedures.

1. 3 This step ensures that the malfunction is present.

Scheme 322

Scheme 323

DTC P0336: CRANKSHAFT POSITION SENSOR CIRCUIT

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Crankshaft Position (CKP) sensor is connected directly to Ignition Control Module (ICM). CKP senor consists of the following circuits

1. 12-volt reference circuit.
2. Low reference circuit.
3. CKP sensor 1 signal circuit.
4. CKP sensor 2 signal circuit.

CKP sensor shares power supply and low reference circuits with camshaft position (CMP) sensor. If the PCM detects no 18X reference pulses in one engine cycle. DTC P0336 sets.

1. Engine is running and 3X reference pulses are being received.

No 18X reference pulses are received in one engine cycle, 720 degrees of crankshaft rotation.

1. The control module illuminates the Malfunction Indicator Light (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 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.

Scheme 324

Scheme 325

DTC P0341: CAMSHAFT POSITION SENSOR PERFORMANCE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Camshaft Position (CMP) sensor is a Hall-Effect type sensor. Sensor produces one signal for each revolution of camshaft to control sequential fuel injection. There are no direct circuits to Powertrain Control Module (PCM). All circuits are between CMP and Ignition Control Module (ICM). These circuits are CMP signal circuit, 12-volt reference circuit, and low reference circuit. PCM compares CMP sensor signal to number of 3X, low-resolution, engine speed signals generated by ICM. Normal ratio of 3X signals is 6 to 1. DTC sets when PCM receives an incorrect number of CMP sensor signals.

Engine is running and 3X reference pulses are being received.

The PCM does not receive CMP sensor reference pulses during one rotation of the camshaft.

1. The control module illuminates the Malfunction Indicator Light (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 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.

Inspect for the following conditions

1. Any secondary ignition wires arcing to a wiring harness and for carbon tracking or other signs of damage.
2. A faulty ignition coil.
3. The ignition control module and the coils for cracks, carbon tracking, or other signs that indicate that the coil secondary circuit is arcing to the ICM or to the ICM wiring harness.
4. For intermittent conditions, see «INTERMITTENT CONDITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__intermittent-conditions) under SELF DIAGNOSTIC SYSTEM.

The numbers below refer to the step numbers in the diagnostic procedures.

1. 14 This test verifies if the sensor is working correctly. By suppling a ground to the circuit, the voltage should change when the circuit is touched with a test light.
2. 26 This step determines if the fault is caused by a missing camshaft magnet or by a faulty PCM. The voltage measured in this step should be near 5 volts, and decrease to near 0 volts when the CMP sensor interfaces with the camshaft magnet.

Scheme 326

Scheme 327

Scheme 328

Scheme 329

DTC P0401: EGR SYSTEM INSUFFICIENT FLOW

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Powertrain Control Module (PCM) tests Exhaust Gas Recirculation (EGR) system during deceleration by momentarily commanding EGR valve to open while monitoring Manifold Absolute Pressure (MAP) senor signal. When EGR valve is opened, PCM should see a proportional increase in MAP. If expected increase in MAP is not seen, PCM notes amount of error that was detected and adjusts an internal fail counter toward a fail threshold level. When fail counter exceeds fail threshold level, PCM will set this DTC. Number of test samples required to accomplish this may vary according to amount of detected flow error.

Normally, PCM will only allow one EGR flow test sample to be taken during an ignition cycle. To aid in verifying a repair, PCM allows up to 12 EGR flow test counts during the first ignition cycle following a code clear event. Between 9-12 EGR flow test counts should be sufficient for the PCM to determine adequate EGR flow and pass the EGR flow test. If the PCM detects an EGR flow error, DTC P0502 sets.

1. DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0201-P0206, P0300, P0336, P0403, P0404, P0502, P0503, P0506, P0507, P1106, P1107, P1112, P1113, P1114, P1115, P1121, P1122, P1374, or P1404 are not set.
2. The ignition 1 signal parameter is 11-18 volts.
3. A/C status does not change.
4. Transaxle range does not change.
5. TP angle is less than one percent.
6. Intake Air Temperature (IAT) is -40 to 248°F (-40 to 140°C).
7. Engine Coolant Temperature (ECT) is more than 167°F (75°C).
8. Engine speed is 1100-1400 RPM.
9. The MAP sensor parameter is 17-43 kPa.
10. The MAF sensor parameter does not change more than 2 grams per second.
11. The BARO parameter is more than 74 kPa.
12. The TP sensor parameter is less than 1 percent.
13. The VSS parameter is more than 28 MPH. during deceleration.
14. Vehicle will need to be driven above 50 MPH, and then allowed to decelerate. When the vehicle is decelerating while meeting all of the criteria, the PCM will enable the test to run. As the test is running, you will see the desired EGR parameter and the EGR position sensor on the scan tool change from zero to a calibrated value above zero. Additionally, the EGR Flow Test Count parameter on the scan tool will increment when each EGR flow test is completed.

The MAP changes monitored by the PCM during the EGR flow tests indicate an insufficient amount of EGR flow.

1. The control module illuminates the Malfunction Indicator Light (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 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.

Inspect for the following conditions

1. Vacuum restriction to MAP sensor. A skewed MAP sensor can cause the PCM to read incorrect MAP changes during the EGR flow test.
2. An engine that is running poorly due to a mechanical condition such as worn piston rings, worn camshaft, etc. These type of conditions can cause low engine vacuum and thus can cause a less than expected MAP change during the flow test.
3. Excessive back pressure in the exhaust system may cause this DTC to set. This condition can cause low engine vacuum and thus can cause a less than expected MAP change during the EGR flow test. Possible causes of this could be a restriction in the exhaust system or non-OEM exhaust parts.
4. Exhaust system leaks cam cause an insufficient amount of EGR flow through the EGR valve. This condition can cause a less than expected MAP change due to insufficient exhaust back pressure. Possible causes of this could be a leaking exhaust system, a leaking EGR pipe or non-OEM exhaust parts.
5. A restriction in the intake manifold such as carbon deposits and casting flash.

The number below refers to the step number in the diagnostic procedures.

1. 2 MAP sensor faults must e diagnosed first. A skewed MAP sensor reading could cause this DTC to set.

Scheme 330

DTC P0403: EGR SOLENOID CONTROL CIRCUIT

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

The Powertrain Control Module (PCM) controls the Exhaust Gas Recirculation (EGR) valve with a solid state device called a driver. The driver supplies the EGR solenoid with 12 volts that is Pulse-Width Modulated (PWM) through the EGR solenoid high control circuit. A ground path is provided by the PCM through the EGR solenoid low control circuit. The driver has the ability to detect an electrical malfunction on the EGR solenoid control circuits. If the PCM determines that the driver has detected an electrical malfunction on one of these circuits, DTC P0403 sets.

1. Engine is cranking or running.
2. System voltage is 11-18 volts.

The PCM detects an electrical malfunction in the EGR solenoid high control circuit or the EGR solenoid low control circuit. The condition must be met for more than 20 seconds.

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

1. The control module turns off the 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 in the diagnostic procedures.

1. 6 This step tests if voltage is constantly being applied to the EGR valve.

Scheme 331

Scheme 332

DTC P0404: EGR OPEN POSITION PERFORMANCE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

The Exhaust Gas Recirculation (EGR) valve position sensor is monitored by the Powertrain Control Module (PCM). The 5-volt reference circuit, low reference circuit and the EGR valve position signal circuit are used by the PCM to determine the EGR valve position. The PCM compares the EGR Position Sensor parameter with the Desired EGR position parameter when the valve is commanded open or closed. If the PCM detects a calibrated difference between the EGR position sensor parameter and Desired EGR position parameter for a calibrated amount of time, DTC P0404 sets.

1. The ignition 1 signal parameter is 11-18 volts.
2. EGR valve is commanded OPEN.

The difference between the EGR position sensor parameter and the desired EGR position parameter is more than 15 percent. The conditions must be met for more than 20 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 control module stores this information in the Freeze Frame/Failure Records.
3. The PCM disables the EGR valve for the ignition cycle.

1. The control module turns off the 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.

Check for excessive deposits on EGR pintle or seat. Remove EGR valve and inspect for deposits that may interfere with EGR valve pintle extending completely or cause pintle to stick.

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

Scheme 333

Scheme 334

DTC P0405: EGR POSITION SENSOR CIRCUIT - LOW VOLTAGE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

The Exhaust Gas Recirculation (EGR) valve position sensor is monitored by the Powertrain Control Module (PCM). The 5-volt reference circuit and the EGR valve position signal circuit are used by the PCM to determine the EGR valve position. If the EGR valve position sensor signal voltage is pulled below a calibrated value, DTC P0405 sets.

1. The Ignition 1 Signal parameter is 11-18 volts.
2. The ignition is ON.

DTC sets when EGR position sensor is less than 0.14 volt for more than 20 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 control module stores this information in the Freeze Frame/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 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 in the diagnostic procedures.

1. 2 By disconnecting each component one at a time, the component that is pulling the 5 volt reference circuit low will be revealed.

Note. If DTC P1635 is set, diagnose that DTC first. See DTC P1635: 5-VOLT REFERENCE CIRCUIT "A" OR NO. 1 .

Scheme 335

Scheme 336

DTC P0410: SECONDARY AIR INJECTION SYSTEM

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Control module activates secondary Air Injection (AIR) system by grounding both pump relay and vacuum control solenoid control circuits simultaneously. This energizes AIR pump and vacuum control solenoid. Vacuum is then applied, opening valves. Pump then forces fresh air into exhaust stream in order to accelerate catalyst operation. Control module will run up to 3 diagnostic tests using pre-catalyst Heated Oxygen Sensor (HO2S) voltage and Short Term Fuel Trim (STFT) to diagnose system. System can be diagnosed during normal secondary air injection operation or control module can activate system specifically for diagnostic purposes. DTC sets when an airflow problem is detected. When inactive, system prevents airflow in either direction.

1. Engine run time is more than 10 seconds.
2. ECT is 40-230°F (4.5-110°C).
3. MAF is 2-25 grams/second.
4. Ignition voltage is more than 10 volts.
5. Engine speed is more than 800 RPM.
6. Fuel system is operating in DECEL control cell.
7. IAT is 40-158°F (4.5-70°C).
8. Short Term Fuel Trim (STFT) is -5 to 5 percent.
9. Engine load is 5-30 percent.
10. BARO is more than 75 kPa.
11. Vehicle speed is more than 25 MPH.
12. DTCs P0102, P0103, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0171, P0172, P0300, P0440, P0442, P0443, P0446, P0449, P0506, P0507, P1111, P1112, P1114, P1115, P1121, P1122, P1133, or P1134 are not set.

DTC sets when pre-catalyst HO2S voltage remains more than a predetermined lean value during test and STFT does not increase a calibrated amount during test. Conditions must exist for 3 consecutive tests.

1. The control module illuminates the Malfunction Indicator Light (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 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 in the diagnostic procedures.

1. 41 The replacement PCM must be programmed.

Note. If DTC P0412 or DTC P0418 are also set, refer to that diagnostic first. See DTC P0412: SECONDARY AIR INJECTION SOLENOID CONTROL CIRCUIT or DTC P0418: SECONDARY AIR INJECTION RELAY CONTROL CIRCUIT .

1. Perform Diagnostic System Check - Engine Controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM. After performing Diagnostic System Check - Engine Controls, go to next step.
2. Check for damage, loose or restricted AIR pipes or hoses, and loose or restricted vacuum lines. Did you find and correct the condition? If yes, go to step 42 . If no, go to next step.
3. Turn ignition on. Using scan tool, command AIR pump relay on and off. Does the AIR pump turn on and off with each command? If yes, go to next step. If no, go to step 10 .
4. Using scan tool, command AIR solenoid on and off. Does the AIR solenoid turn on and off with each command? If yes, go to next step. If no, go to step 14 .
5. Disconnect AIR hose from shutoff valve (pump side). Using scan tool, command AIR pump on. Is airflow present at hose outlet? If yes, go to next step. If no, go to step 16 .
6. Disconnect vacuum line (source) from solenoid. Start engine. Is vacuum present at vacuum line? If yes, go to next step. If no, go to step 24 .
7. Reconnect vacuum line to solenoid. Disconnect vacuum line from shutoff valve. Start engine. Using scan tool, command AIR solenoid on. Is vacuum present at vacuum line? If yes, go to next step. If no, go to step 17 .
8. Remove shutoff valve from vehicle. Install a hand-held vacuum pump to valve. Apply 10 in. Hg vacuum to valve. Does the valve hold vacuum for one minute? If yes, go to next step. If no, go to step 33 .
9. Leave vacuum applied to valve. Attempt to blow through valve from inlet side. Can you blow through valve? If yes, go to step 25 . If no, go to step 33 .
10. Does pump run continuously? If yes, go to step 18 . If no, go to next step.
11. Remove the AIR pump relay. Turn ignition on, with engine off. Probe the relay battery positive and the ignition 1 voltage circuits with a test light connected to a good ground. Does the test light illuminate when probing both circuits? If yes, go to next step. If no, go to step 20 .
12. Probe the AIR pump relay control circuit with a test light that is connected to battery voltage. Command the AIR pump relay on and off with a scan tool. Does the test light turn on and off with each command? If yes, go to next step. If no, go to step 23 .
13. Connect a 30-amp fused jumper wire between the battery positive circuit switched side of the AIR relay and the AIR pump supply voltage circuit of the AIR relay. Turn ignition on, with engine off. Does the AIR pump turn on? If yes, go to step 34 . If no, go to step 26 .
14. Disconnect the AIR vacuum solenoid. Turn ignition on, with engine off Probe the ignition 1 voltage circuit of the AIR solenoid with a test light that is connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step 20 .
15. Probe the AIR solenoid control circuit with a test light that is connected to battery voltage. Command the AIR solenoid on and off with a scan tool. Does the test light turn on and off with each command? If yes, go to step 36 . If no, go to step 23 .
16. Remove the AIR hose from the pump. Command the AIR Pump on with a scan tool. Is airflow pressure present at the pump outlet? If yes, go to step 25 . If no, go to step 39 .
17. Inspect the vacuum line from the solenoid to the valve for a restriction or a loose condition. Did you find and correct the condition? If yes, go to step 42 . If no, go to step 37 .
18. Ensure the ignition is on, with the engine off. Remove the relay. Does the AIR pump turn off? If yes, go to next step. If no, go to step 28 .
19. Probe the AIR pump relay control circuit with a test light that is connected to battery voltage. Command the AIR pump on and off with a scan tool. Does the test light turn on and off with each command? If yes, go to step 35 . If no, go to step 29 .
20. Test the AIR fuse and the ignition 1 fuses. Are the fuse or fuses okay? If yes, go to step 30 . If no, go to next step.
21. Test the voltage circuit corresponding to the open fuse or fuses for a short to ground. Did you find and correct the condition? If yes, go to step 42 . If no, go to next step.
22. Test the AIR pump supply voltage circuit for a short to ground. Did you find and correct the condition? If yes, go to step 42 . If no, go to step 39 .
23. Is the test light on steady? If yes, go to step 29 . If no, go to step 32 .
24. Repair vacuum source. After repairs go to step 42 .
25. Repair pipe, hose or check valve for open or restriction. After repairs go to step 42 .
26. Ensure the ignition is on, with the engine off. Ensure that the jumper wire is still installed. Disconnect the pump. Connect a test light between the AIR pump supply voltage circuit and the ground circuit of the AIR pump harness connector. Does the test light illuminate? If yes, go to step 38 . If no, go to next step.
27. Ensure the ignition is on, with the engine off. Ensure the jumper wire is still installed. Disconnect the pump. Probe the AIR pump supply voltage circuit with a test light connected to a good ground. Does the test light illuminate? If yes, go to step 31 . If no, go to step 30 .
28. Repair short to voltage in Red wire between pump and pump relay. After repairs, go to step 42 .
29. Test for a short to ground in the AIR pump relay control circuit. Did you find and correct the condition? If yes, go to step 42 . If no, go to step 41 .
30. Repair the open in the AIR pump supply voltage circuit. After repairs, go to step 42 .
31. Repair the open or high resistance in the AIR pump ground circuit. After repairs, go to step 42 .
32. Test for an open or short to voltage in the control circuit. Did you find and correct the condition? If yes, go to step 42 . If no, go to step 40 .
33. Replace shut-off valve. After repairs, go to step 42 .
34. Check pump relay connector for poor connections. If problem was found, repair as necessary. After repairs, go to step 42 . If problem was not found, go to next step.
35. Replace pump relay. After repairs, go to step 42 .
36. Check solenoid connector for poor connections. If problem was found, repair as necessary. After repairs, go to step 42 . If problem was not found, go to next step.
37. Replace AIR solenoid. After repairs, go to step 42 .
38. Test for poor connections at the pump. Did you find and correct the condition? If yes, go to step 42 . If no, go to next step.
39. Replace AIR pump. After repairs, go to step 42 .
40. Test for poor connections at PCM. Did you find and correct the condition? If yes, go to step 42 . If no, go to next step.
41. Replace PCM. Program replacement PCM. See «POWERTRAIN CONTROL MODULE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under PROGRAMMING. After repairs, go to next step.
42. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within Conditions for Running DTC. Does DTC run and pass? If yes, go to next step. If no, go to step 2 .
43. Using scan tool, observe stored information. Does scan tool displays any DTCs that have not been diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) . If no, system is okay.

If DTC cannot be duplicated and is determined to be intermittent, reviewing freeze frame/failure records can be useful in determining when DTC was last set. Also, see INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM.

A short to voltage in pump relay control circuit can result in AIR pump running continuously with ignition off by backfeeding to ground. This will eventually result in pump failure.

An AIR pump that had become inoperative and had shown indications of having exhaust gases in outlet port would indicates check valve failure.

DTC P0412: SECONDARY AIR INJECTION SOLENOID CONTROL CIRCUIT

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Ignition voltage is supplied directly to secondary Air Injection (AIR) vacuum control solenoid. Powertrain Control Module (PCM) controls AIR solenoid by grounding control circuit via an internal solid state device called a driver. Primary function of driver is to supply ground for component being controlled. Each driver has a fault line which is monitored by PCM. When PCM is commanding a component on, voltage of control circuit should be about zero volts. When PCM is commanding control circuit to a component off, voltage potential of circuit should be about battery voltage. DTC sets when fault detection circuit senses a voltage other than what is expected. PCM will monitor control circuit for a short to ground, short to voltage, open circuit, open solenoid, internally-shorted or excessively low resistance solenoid. When the PCM detects any of the stated malfunctions, this DTC will set and the affected driver will be disabled.

1. Ignition voltage is 9-18 volts.
2. Engine speed more than 80 RPM.
3. PCM driver transitions from on to off or off to on.

DTC sets when a short to ground, open circuit, or short to battery voltage is detected on control circuit for at least 30 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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 in the diagnostic procedures.

1. 1 The Diagnostic System Check - Engine Controls prompts you to complete some basic checks and store the Freeze Frame/Failure Records on the scan tool.
2. 2 Listen for an audible click when the solenoid operates. Command both the on and off states. Repeat the commands as necessary.
3. 3 Tests for voltage at the feed side of the solenoid.
4. 4 Verifies that the PCM is providing ground to the solenoid.
5. 5 Tests if ground is constantly being applied to the solenoid.
6. 12 The PCM utilizes Electrically Erasable Programmable Read Only Memory (EEPROM). If the PCM is replaced, the new PCM must be programmed.

1. Perform Diagnostic System Check - Engine Controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM. After performing Diagnostic System Check - Engine Controls, go to next step.
2. Turn ignition on, with engine off. Command the secondary Air Injection (AIR) solenoid on and off with a scan tool. Does the AIR solenoid turn on and off with each command? If yes, see «DIAGNOSTIC AIDS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) . If no, go to next step.
3. Turn off the ignition. Disconnect the solenoid. Turn ignition on, with engine off. Probe the ignition 1 voltage circuit with a test light that is connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step 10 .
4. Connect a test light between the control circuit and the ignition 1 voltage circuit of the solenoid. Command the AIR solenoid on and off with a scan tool. Does the test light turn on and off with each command? If yes, go to step 8 . If no, go to next step.
5. Does the test light remain illuminated with each command? If yes, go to step 7 . If no, go to next step.
6. Test the control circuit of the solenoid for the following conditions: A short to voltage. High resistance. An open. Repair as necessary. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 9 .
7. Test the control circuit of the solenoid for a short to ground. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 9 .
8. Inspect for poor connections at the AIR solenoid. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 11 .
9. Inspect for poor connections at PCM. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 12 .
10. Test for a short to ground or open in the coil feed circuit. Did you find and correct the condition? If yes, go to step 13 . If no, go to next step.
11. Replace AIR solenoid. After replacing solenoid, go to step 13 .
12. Replace PCM. Program replacement PCM. See «POWERTRAIN CONTROL MODULE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under PROGRAMMING. After repairs, go to next step.
13. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within Conditions for Running DTC. Does DTC run and pass? If yes, go to next step. If no, go to step 2 .
14. Using scan tool, observe stored information. Does scan tool displays any DTCs that have not been diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) . If no, system is okay.

Always use Connector Test Adapter Kit (J 35616-A) or Flat Wire Probe Adapter Kit (J 42675) to front probe terminals. Do not use paper clips or other substitutes as they can damage terminals and cause incorrect measurements.

Do not operate AIR pump for more than 60 seconds. Continuous operation of AIR pump in excess of 60 seconds will damage AIR pump.

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

An AIR pump that had become inoperative and had shown indications of having exhaust gases in the outlet port would indicate check valve failure.

DTC P0418: SECONDARY AIR INJECTION RELAY CONTROL CIRCUIT

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Ignition voltage is supplied directly to relay. Powertrain Control Module (PCM) supplies ground path to relay control circuit via an internal solid state device called a driver. Each driver has a fault line which is monitored by PCM. When PCM commands relay on, voltage on control circuit should be low, about zero volts. When PCM commands relay off, voltage on control circuit should be high, about battery voltage. DTC sets when fault detection circuit senses a voltage other than what is expected. PCM will monitor control circuit for a short to ground, short to voltage, open circuit, open relay, internally shorted or excessively low resistance relay.

1. Ignition voltage is 9-18 volts.
2. Engine speed is more than 80 RPM.
3. PCM driver transitions from on to off or from off to on.

DTC sets when a short to ground, open circuit, or short to battery voltage is detected on control circuit for at least 30 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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 in the diagnostic procedures.

1. 1 The Diagnostic System Check - Engine Controls prompts you to complete some basic checks and store the Freeze Frame/Failure Records on the scan tool.
2. 2 Listen for a click when the relay operates. Command both the on and off states. Repeat the commands as necessary.
3. 3 This step tests for voltage at the feed.
4. 4 This step verifies that the control module is providing a ground.
5. 5 This step tests if ground is constantly being applied.
6. 12 The control module utilizes Electrically Erasable Programmable Read Only Memory (EEPROM). When the control module is replaced, the new control module must be programmed.

1. Perform Diagnostic System Check - Engine Controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM. After performing Diagnostic System Check - Engine Controls, go to next step.
2. Turn ignition on, with engine off. Command the secondary Air Injection (AIR) pump and relay on and off with a scan tool. Does the relay turn on and off with each command? If yes, see «DIAGNOSTIC AIDS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) . If no, go to next step.
3. Turn off the ignition. Remove the AIR relay. Turn ignition on, with engine off. Probe the ignition 1 voltage circuit, coil side, of the AIR relay with a test light that is connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step 12 .
4. Connect a test light between the control circuit of the AIR relay connector and the ignition 1 voltage circuit of the AIR relay connector. Command the AIR pump relay on and off with a scan tool. Does the test light turn on and off with each command? If yes, go to step 11 . If no, go to next step.
5. Does the test light remain illuminated with each command? If yes, go to step 7 . If no, go to next step.
6. Test the control circuit for a short to voltage or an open and repair as necessary. Did you find and correct the condition? If yes, go to step 16 . If no, go to step 11 .
7. Test the control circuit for a short to ground and repair as necessary. Did you find and correct the condition? If yes, go to next step. If no, go to step 15 .
8. Install the AIR relay. Turn ignition on, with engine off. Command the AIR relay on and off with a scan tool. Does the AIR pump turn on and off with each command? If yes, go to step 16 . If no, go to next step.
9. Replace the AIR fuse as necessary. Disconnect the AIR pump connector. Connect a test light between the AIR supply voltage circuit of the AIR pump connector and the ground circuit of the AIR pump connector. Command the AIR pump relay on and off with a scan tool. Does the test light turn on and off with each command? If yes, go to step 13 . If no, go to next step.
10. Test for an intermittent and for a poor connection at the relay connector and repair as necessary. Did you find and correct the condition? If yes, go to step 16 . If no, go to step 14 .
11. Test for an intermittent and for a poor connection at PCM. Did you find and correct the condition? If yes, go to step 16 . If no, go to step 15 .
12. Repair open or short to ground in ignition 1 voltage circuit. After repairs, go to step 16 .
13. Replace AIR pump. After repairs, go to step 16 .
14. Replace AIR relay. After repairs, go to step 16 .
15. Replace PCM. Program replacement PCM. See «POWERTRAIN CONTROL MODULE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under PROGRAMMING. After repairs, go to next step.
16. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within Conditions for Running DTC. Does DTC run and pass? If yes, go to next step. If no, go to step 2 .
17. Using scan tool, observe stored information. Does scan tool displays any DTCs that have not been diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) . If no, system is okay.

Always use Connector Test Adapter Kit (J 35616-A) or Flat Wire Probe Adapter Kit (J 42675) to front probe terminals. Do not use paper clips or other substitutes as they can damage terminals and cause incorrect measurements.

Do not operate AIR pump for more than 60 seconds. Continuous operation of AIR pump in excess of 60 seconds will damage AIR pump.

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

An AIR pump that had become inoperative and had shown indications of having exhaust gases in the outlet port would indicate check valve failure.

DTC P0420: CATALYST SYSTEM LOW EFFICIENCY

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

To control emissions of Hydrocarbons (HC), Carbon Monoxide (CO), and Oxides Of Nitrogen (NOx), a 3-way catalytic converter is used. Catalyst within converter promotes a chemical reaction which oxidizes HC and CO present in exhaust gas, converting HC and CO into harmless water vapor and carbon dioxide. Catalyst also reduces NOx by converting NOx to nitrogen. Converter also has ability to store excess oxygen and release stored oxygen to promote these reactions. This Oxygen Storage Capacity (OSC) is a measurement of catalysts ability to control emissions. Powertrain Control Module (PCM) monitors this process using a Heated Oxygen Sensor (HO2S) located in exhaust stream past 3-way converter. When catalyst is functioning properly, HO2S 2 is slow to respond to a large change in HO2S 1 signal. When HO2S 2 responds quickly to a large change in HO2S 1 signal, OSC and efficiency of catalyst are considered to be degraded and MIL will be illuminated if subsequent tests also indicate a failure.

Conditions For Running DTC (Except LeSabre)

1. Meet conditions for engine warm up. Using scan tool in catalyst data list, verify the following: DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0171, P0172, P0201-P0206, P0300, P0325, P0327, P0336, P0341, P0401, P0403, P0404, P0405, P0440, P0442, P0443, P0446, P0449, P0502, P0503, P0506, P0507, P1133, P1134, P1336, P1351, P1352, P1361, P1362, P1374, P1404, or P1441 are not set. Engine has been running more than 10 minutes. Engine Coolant Temperature (ECT) is 158-255°F (70-124°C). Barometer (BARO) is more than 75 kPa. Vehicle is in closed loop. Intake Air Temperature (IAT) is more than -4 to 212°F (-20 to 100°C). Battery voltage is more than 10.7 volts.
2. Warm up catalyst. Fully open the hood. Set transmission is in Park (A/T) or in Neutral (M/T). Set parking brake. Press and HOLD service brake. Each time engine is started, diagnostic can run up to 18 times. After 10-minute run time and before diagnostic runs first time, engine must run an additional 5 minutes between 1500-2500 RPM. Any additional tests on same key cycle, engine speed must be 1500-2500 RPM for one minute. To activate diagnostic, return engine to idle and put vehicle in Drive, or depress clutch for a manual transmission.
3. Test catalyst. Transmission in Drive (A/T) or in Neutral (M/T with clutch depressed). Within 60 seconds, the air fuel ratio will go lean below 14.1 for up to 7 seconds, and then may go rich, above 15.3, for up to 7 seconds. Use the scan tool in order to determine if DTC P0420 has passed or failed this key cycle.

Conditions For Running (LeSabre Only)

1. Meet the conditions for engine warm up. Use the scan tool catalyst data list in order to verify the following: DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0130, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0171, P0172, P0201-P0206, P0300, P0336, P0341, P0401, P0403, P0404, P0405, P0410, P0412, P0418, P0440, P0442, P0443, P0446, P0449, P0502, P0503, P0506, P0507, P1133, P1134, P1336, P1351, P1352, P1361, P1374, P1441 are not set. The engine has been running more than 10 minutes. The Engine Coolant Temperature (ECT) is above 158°F (70°C) and below 255°F (124°C). The Barometric Pressure (BARO) is above 75 kPa. The vehicle is in Closed Loop. The Intake Air Temperature (IAT) is above -4°F (-20°C) and less than 212°F (100°C). The battery voltage is above 10.7 volts.
2. Warm up the catalyst. Fully open the hood. Place the transmission in Park (A/T) or Neutral (M/T). Set parking brake. Press and hold the service brake. Each time the engine is started, the diagnostic can run up to 18 times. After the 10 minute run time and before the diagnostic runs and the first time, the engine must run an additional 5 minutes between 1500-2500 RPM. For any additional Tests on the same key cycle, the engine speed must be between 1500-2500 RPM for 1 minute. In order to activate the diagnostic return the vehicle to idle and put the vehicle in drive, or depress the clutch for a manual transmission.
3. Test the catalyst. Place the transmission in drive (automatic) or neutral (for manuals with clutch depress). VIN K California Emissions Within 60 seconds the air fuel ratio will go rich below 14.1 for up to 6 seconds, then it may go lean above 15.3 for up to 8 seconds. VIN K Federal Emissions Within 60 seconds the air fuel ratio will go lean above 15.3 for up to 6 seconds, then may go rich below 14.1 for up to 7 seconds. VIN 1 Within 60 seconds the air fuel ratio will go rich below 14.1 for up to 7 seconds, then it may go lean above 15.3 for up to 9 seconds. Check if DTC P0420 has passed or failed this key cycle using the scan tool.

DTC sets when PCM determines catalysts oxygen storage capacity is less than an acceptable threshold.

1. The control module illuminates the Malfunction Indicator Light (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 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 (Except LeSabre)

Check for the following conditions

1. PCM will not enable catalyst test until the following conditions are met: Engine speed is within 200 RPM from desired idle. Throttle Position (TP) is 1.5 percent or less. Short term integrator is -20-20 percent.
2. Catalyst test will abort if vehicle conditions fall outside conditions listed below while test is running: Engine speed is within 200 RPM from desired idle. Throttle Position (TP) is 1.5 percent or less. Short term integrator is -20 to 20 percent.
3. The catalyst test may abort due to a change in the engine load. If this condition occurs, use the scan tool on order to force the cooling fans ON. Repeat this set.
4. The number of attempted tests is limited to 18 per key cycle.
5. More than 6 tests may have to be attempted in order to get 6 completed tests. An aborted test counts as an attempted test.
6. If 18 tests have been attempted and if a decision has not been made during this key cycle, turn the key OFF for 30 seconds, start engine, and perform the conditions for running the DTC, including the 10-minute run time.
7. After returning to an idle the HO2S 1 signal may stay rich or lean for several seconds, causing the test to be delayed.

Diagnostic Aids (LeSabre Only)

Check for the following conditions

1. the PCM will not enable the catalyst test until the following conditions are met: The engine speed is plus or minus 100 RPM from the desired idle. The Throttle Position (TP) is zero percent. The short term integrator is -20 percent and 20 percent.
2. The catalyst test will abort if the vehicle falls outside the conditions listed above while the test is running.
3. The catalyst test may abort due to a change in engine load, for example, from the A/C or from the coolant fan. If this condition occurs, use the scan tool in order to force the cooling fans ON, and return to step 2 .
4. More than 6 tests may have to be attempted in order to get 6 completed tests. An aborted test counts as an attempted test. The number of attempt tests is limited to 18 per key cycle. After returning to an idle the HO2S 1 signal may stay rich or lean for several seconds causing the test to be delayed.
5. Faulty Connection At PCM Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals. and poor terminal to wire connection. Use a corresponding mating terminals to test for correct terminal tension.
6. Damaged Harness Inspect the wiring harness for damage. If the harness appears to be OK, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the display will indicated the location of the fault.

The numbers below refer to the step numbers in the diagnostic procedures.

1. 2 If any component DTCs are set, diagnose those DTCs first. A fault in a component can cause the converter to appear degraded or may have caused its failure.
2. 3 Clearing the DTCs allows the catalyst test to be completed up to 18 times and completed up to 6 times this ignition cycle. If the A/C is not turned OFF the diagnostic will not run. The engine must be warmed-up. The converter needs to be warmed-up by raising the engine speed above idle for the specified time prior to each attempted test. Check and see if DTC passed or failed this ignition cycle. If the DTC does not pass or fail look for a possible reason that would cause the test to abort.
3. 4 This step includes tests for conditions that can cause the TWC to appear degraded. Repair any problems found before proceeding with this table.
4. 9 If the three-way converter needs to be replaced, make sure that another condition is not present which could damage the converter. These conditions may include misfire, leaking or plugged fuel injectors, high engine oil or coolant consumption, retarded spark timing or weak spark. Correct any possible causes of converter damage before replacing the converter.

Scheme 337

Scheme 338

DTC P0440: EVAP SYSTEM

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

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 valve OPEN and the EVAP vent 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 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 EVAP VALVE LOGIC table illustrates the relationship between the on and off states, and the open or closed states of the EVAP canister purge and vent valves.

EVAP VALVE LOGIC

1. DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0443, P0449, P0452, P0453, P1106, P1107, P1112, P1114, P1115, P1121, or P1122 are not set.
2. The engine is running.
3. Ignition voltage is 10-18 volts.
4. Barometric (BARO) pressure is more than 75 kPa.
5. Fuel level is 15-85 percent.
6. Engine Coolant Temperature (ECT) is 39-86°F (4-30°C).
7. Intake Air Temperature (IAT) is 39-86°F (4-30°C).
8. Start-up ECT and IAT are within 16°F (9°C) of each other.
9. Vehicle Speed Sensor (VSS) is less than 75 MPH.

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

1. The control module illuminates the Malfunction Indicator Light (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 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.

To help locate intermittent leaks, use the Evaporative Emissions System Tester (J 41413-20) to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the High Intensity White Light (J 41413-SPT).

A temporary blockage in EVAP canister purge valve, purge pipe or EVAP canister could cause an intermittent condition. Inspect and repair any restriction in the EVAP system.

To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the High Intensity White Light (J 41413-SPT).

Reviewing Freeze Frame/Failure Records vehicle mileage since diagnostic test last failed may help determine how often condition that caused DTC to be set occurs. This may assist in diagnosing condition.

The numbers below refer to the step numbers in the diagnostic procedures.

1. 2 This step verifies that a failure condition is active.
2. 4 Introducing smoke in 15 second intervals may allow smaller leak areas to be more noticeable. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.
3. 6 This step verifies proper operation of the FTP sensor.
4. 7 A normal operating FTP sensor should increase above 5 in. H2O and stop between 6-7 in. H2O.
5. 9 This step tests the EVAP purge solenoid vacuum source between the EVAP purge solenoid and the intake manifold for restrictions or blockages.

Scheme 339

Scheme 340

Scheme 341

DTC P0442: EVAP CONTROL SYSTEM SMALL LEAK DETECTED

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

This DTC tests Evaporative (EVAP) emission system for a small leak. Powertrain Control Module (PCM) monitors Fuel Tank Pressure (FTP) sensor signal to determine vacuum decay rate. At an appropriate time, PCM turns EVAP canister purge valve on and EVAP vent valve on. This allows engine to draw a vacuum on EVAP system. At a calibrated time, or vacuum level, PCM turns EVAP canister purge valve off, sealing system, and monitors FTP sensor input to determine EVAP system vacuum decay. DTC sets when PCM detects a leak larger than a calibrated amount.

For the relationship between the on and off states, and the open or closed states of the EVAP canister purge and vent valves, see EVAP VALVE LOGIC table under DTC P0440: EVAP SYSTEM.

1. DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0440, P0443, P0449, P0452, P0453, P1106, P1107, P1112, P1114, P1115, P1121, or P1122 are not set.
2. Ignition voltage is 10-18 volts.
3. Barometric (BARO) pressure is more than 75 kPa.
4. Fuel level is 15-85 percent.
5. Engine Coolant Temperature (ECT) is 39-86°F (4-30°C).
6. Intake Air Temperature (IAT) is 39-86°F (4-30°C).
7. Start-up ECT and IAT are within 16°F (9°C) of each other.
8. The Vehicle Speed Sensor (VSS) is less than 75 MPH.

DTC sets when EVAP system can achieve vacuum, but a vacuum decay is detected during diagnostic test.

1. The control module illuminates the Malfunction Indicator Light (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 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.

To help locate intermittent leaks, use EVAP Pressure and Purge Station (J 41413) to pressurize EVAP system. Move all EVAP components while testing with Ultrasonic Leak Detector (J 41416).

The numbers below refer to the step numbers in the diagnostic procedures.

1. 2 This step verifies that a failure condition is present.
2. 4 Introducing smoke in 15 second intervals may allow smaller leak areas to be more noticeable. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.
3. 6 This step verifies that repairs are complete and that there are no other leaks in the system.

Scheme 342

Scheme 343

DTC P0443: EVAP PURGE SOLENOID CONTROL CIRCUIT

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

An ignition voltage is supplied directly to Evaporative (EVAP) emission purge valve. EVAP purge valve is Pulse Width Modulated (PWM). Powertrain Control Module (PCM) controls EVAP purge valve on time by grounding control circuit via an internal switch called a driver. Scan tool displays amount of on time as a percentage. PCM monitors status of driver. DTC sets when control module detects an incorrect voltage for commanded state of driver. If the control module detect an incorrect voltage for the commanded state of the driver, this DTC sets.

1. Engine speed is more than 400 RPM.
2. System voltage is 6-18 volts.

DTC sets when PCM detects commanded state of driver and actual state of control circuit do not match for a minimum of 5 seconds.

1. The control module will illuminate the Malfunction Indicator Light (MIL) during the second consecutive trip in which the diagnostic test ran and failed.
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/Failure Records.

1. The control module turns off the 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 in the diagnostic procedures.

1. 2 This step tests if the concern is active. The EVAP purge valve is Pulse-Width Modulated (PWM). An audible clicking should be heard when the purge valve is commanded to 50 percent and should stop when the EVAP purge valve is commanded to zero percent. The rate at which the valve cycles should increase as the commanded state is increased and decreased as the commanded state is decreased. Repeat the commands as necessary.
2. 5 This step tests if a ground is constantly being applied to the EVAP purge solenoid.
3. 6 This step verifies that the control module is providing ground to the EVAP purge solenoid.

Scheme 344

Scheme 345

DTC P0446: EVAP VENT SYSTEM PERFORMANCE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

This DTC tests Evaporative (EVAP) emission system for a restricted or blocked EVAP vent path. Powertrain Control Module (PCM) commands EVAP canister purge valve on and EVAP canister vent valve on. This allows a vacuum to be applied to EVAP system. Once a calibrated vacuum level has been reached, PCM commands EVAP canister purge valve off and EVAP canister vent valve off. PCM monitors Fuel Tank Pressure (FTP) sensor for a decrease in vacuum. DTC sets when vacuum does not decrease to about zero in. H2O in a calibrated time.

For the relationship between the on and off states, and the open or closed states of the EVAP canister purge and vent valves, see EVAP VALVE LOGIC table under DTC P0440: EVAP SYSTEM.

1. DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0440, P0443, P0449, P0452, P0453, P1106, P1107, P1111, P1112, P1114, P1115, P1121, or P1122 are not set.
2. Ignition voltage is 10-18 volts.
3. Barometric (BARO) pressure is more than 75 kPa.
4. Fuel level is 15-80 percent.
5. Engine Coolant Temperature (ECT) is 39-86°F (4-30°C).
6. Intake Air Temperature (IAT) is 39-86°F (4-30°C).
7. Start-up ECT and IAT are within 16°F (9°C) of each other.
8. Vehicle Speed Sensor (VSS) is less than 75 MPH.

DTC sets when FTP is less than -10 in. H2O for as long as 30 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 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 a damaged EVAP vent housing, a temporary blockage at EVAP vent valve inlet or a pinched vent hose. A blockage in vent system will also cause a poor fuel fill problem.

The number below refers to the step number in the diagnostic procedures.

1. 5 This test step determines if the failure is present or intermittent.

Scheme 346

Scheme 347

DTC P0449: EVAP VENT SOLENOID VALVE CONTROL CIRCUIT

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

An ignition voltage is supplied directly to Evaporative (EVAP) emissions canister vent valve. Powertrain Control Module (PCM) controls EVAP vent valve by grounding control circuit via an internal switch called a driver. Primary function of driver is to supply ground for controlled component. PCM monitors status of driver. DTC sets when PCM detects an incorrect voltage for commanded state of driver.

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

The control module detects that the commanded state of the driver and the actual state of the control circuit do not match. Conditions are present for a minimum of 5 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 reports a failure, 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 MIL during the third consecutive trip in which the diagnostic ran and passed.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. The history DTC will clear after 40 consecutive warm-up cycles without a malfunction.
4. Use the scan tool in order to clear the DTC.

The numbers below refer to the step numbers in the diagnostic procedures.

1. 2 Listen or feel for a click when the EVAP vent solenoid operates. Ensure that both the ON and the OFF states are commanded. Repeat the commands as necessary.
2. 5 This step verifies that the control module is providing ground to the EVAP vent solenoid.
3. 6 This step tests if the EVAP vent solenoid control circuit is grounded.

Scheme 348

Scheme 349

DTC P0452: FUEL TANK PRESSURE SENSOR CIRCUIT - LOW VOLTAGE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

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. See FTP SENSOR SIGNAL VOLTAGE & EVAP SYSTEM PRESSURE/VACUUM .

FTP SENSOR SIGNAL VOLTAGE & EVAP SYSTEM PRESSURE/VACUUM

1. The key is ON.

DTC sets when FTP sensor voltage is less than 0.1 volt for more than 5 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns off the 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 in the diagnostic procedures.

1. 5 This step tests for the proper operation of the circuit in the high voltage range.

Scheme 350

Scheme 351

DTC P0453: FUEL TANK PRESSURE SENSOR CIRCUIT - HIGH VOLTAGE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

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. See FTP SENSOR SIGNAL VOLTAGE & EVAP SYSTEM PRESSURE/VACUUM .

1. The key is ON.

DTC sets when FTP sensor voltage is more than 4.9 volts for more than 5 seconds.

1. The control module illuminates the Malfunction Indicator Light (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 failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module will turn off the MIL during the third consecutive trip in which the diagnostic ran and passed.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
4. Use the scan tool in order to clear the DTC.

The number below refers to the step number in the diagnostic procedures.

1. 2 If DTC P1639 set, the 5-volt reference circuit is shorted to a voltage.

Scheme 352

Scheme 353

DTC P0502: VEHICLE SPEED SENSOR CIRCUIT - LOW OUTPUT

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Vehicle Speed Sensor (VSS) system is a pulse generator consisting of a speed sensor assembly, located in case extension, and a toothed vehicle speed sensor reluctor wheel, which is pressed onto final drive carrier assembly. As vehicle drives forward, vehicle speed sensor reluctor wheel rotates. This rotation produces a variable AC signal in pick-up coil that is proportional to vehicle speed. PCM uses this signal to calculate vehicle speed, shift timing and gear ratios. This information is then sent to the PCM to indicate how fast the vehicle is traveling and to develop the shift pattern for the transmission. Other systems also use VSS information

1. TCC apply and release.
2. Cruise control system.
3. Fuel delivery systems.

DTC sets when PCM detects a low vehicle speed with a high engine speed while in a drive range.

1. TP angle is more than 12 percent.
2. Engine torque is 40-300 ft. lbs. (55-400 N.m).
3. Transmission is not in Park or Neutral.
4. Input shaft speed is more than 1500 RPM.
5. DTCs P0106, P0107, P0108, P0121, P0122, P0123, P0716, P0717, P1106, P1107, P1121, P1122, or P1810 are not set.

DTC sets when output shaft speed is less than 150 RPM for 2.5 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) during the second consecutive trip in which the Conditions for Setting DTC are met.
2. The PCM commands maximum line pressure.
3. The PCM freezes shift adapts.
4. The PCM calculates vehicle speed from the AT input shaft speed sensor for shift timing.
5. The PCM records the operating conditions when the Conditions for Setting DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
6. The PCM stores DTC P0502 in PCM history during the second consecutive trip in which the Conditions for Setting DTC are met.

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

The numbers below refer to the step numbers in the diagnostic procedures.

1. 3 This step test the ability of the VSS to produce an AC voltage. This step also verifies the integrity of the wiring to the PCM.
2. 4 This step test the VSS circuit for correct resistance.

1. Perform Diagnostic System Check - Engine Controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM. After performing Diagnostic System Check - Engine Controls, go to next step.
2. Install a scan tool. Turn ignition on, engine off. Record FREEZE FRAME/FAILURE RECORDS. Clear DTCs. Raise and support drive wheels. Start and idle engine. Place transmission in Drive. Monitor transmission VSS on scan tool. With drive wheels rotating, increase and decrease throttle position. Does the Transmission VSS RPM increase when wheel speed increases? If yes, see «INTERMITTENT CONDITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__intermittent-conditions) under SELF-DIAGNOSTIC SYSTEM. If no, go to next step.
3. Turn off the ignition. Disconnect the PCM connector C1. Using the Connector Test Adapter Kit (J 35616-A), connect the DVOM between terminals C1-64 and C1-65 of the PCM harness connector. Select AC volts on the DVOM. Turn ignition on, with engine off. Place the range selector in a Drive range or Neutral. Rotate the right front drive wheel by hand, while observing the DVOM display. Does the voltage measure greater than 0.4 volt AC? If yes, go to step 8 . If no, go to next step.
4. Leave the DVOM test leads connected between terminals C1-64 and C1-65 of the PCM harness connector. Select ohms on the DVOM. Measure the resistance of the complete VSS circuit. Is the circuit resistance 1650-3180 ohms? If yes, go to step 9 . If no, go to next step.
5. Is the resistance more than 3180 ohms? If yes, go to step 11 . If no, go to next step.
6. Leave the DVOM test leads connected between terminals C1-64 and C1-65 of the PCM harness connector. Disconnect the VSS connector at the transmission. Test the high signal circuit (CKT 400) and the low signal circuit (CKT 401) of the VSS for a short together. Measure from PCM connector terminal C1-64 to C1-65. Are the signal and ground circuits shorted together? If yes, go to next step. If no, go to step 14 .
7. Repair the short between the high signal circuit (CKT 400) and the low signal circuit (CKT 401). After repairs, go to step 16 .
8. Test the high signal circuit (CKT 400) of the VSS for a short to ground between the PCM and the VSS. Did you find and correct the condition? If yes, go to step 16 . If no, go to step 15 .
9. Reconnect PCM connector C1. Select DC volts on DVOM. Connect DVOM between terminals "A" and "B" of the VSS vehicle harness. Turn ignition on, with engine off. Does the DVOM display greater than one volt? If yes, go to next step. If no, go to step 13 .
10. Repair the short to power in the high signal circuit (CKT 400). After repairs, go to step 16 .
11. Test the high signal circuit (CKT 400) of the VSS for an open between the PCM and the VSS. Did you find and correct the condition? If yes, go to step 16 . If no, go to next step.
12. Test the low signal circuit (CKT 401) of the VSS for an open between the PCM and the VSS. Did you find and correct the condition? If yes, go to step 16 . If no, go to step 14 .
13. Remove VSS. Inspect VSS and transmission for the following: Incorrect VSS. VSS damage. Excessive runout in final drive carrier assembly. Excessive VSS to speed sensor rotor gap. Incorrect speed sensor rotor alignment. Speed sensor rotor damage. If problem was found, repair as necessary. See appropriate OVERHAUL article in AUTOMATIC TRANSMISSIONS. Did you find and correct the condition? If yes, go to step 16 . If no, go to next step.
14. Replace VSS. After repairs, go to step 16 .
15. Replace PCM. Program replacement PCM. See «POWERTRAIN CONTROL MODULE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under PROGRAMMING. After repairs, go to next step.
16. To verify repair, select DTC. Select CLEAR INFO. Drive vehicle. Ensure transmission VSS is more than 250 RPM for at least 2 seconds. Select SPECIFIC DTC. Enter DTC P0502. If test has run and passed, system is okay. If test did not rum and pass, go to step 2 .

DTC P0503: VEHICLE SPEED SENSOR CIRCUIT - ERRATIC OUTPUT

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Vehicle Speed Sensor (VSS) system is a pulse generator consisting of a speed sensor assembly, located in case extension, and a toothed vehicle speed sensor reluctor wheel, which is pressed onto final drive carrier assembly. As vehicle drives forward, vehicle speed sensor reluctor wheel rotates. This rotation produces a variable AC signal in pick-up coil that is proportional to vehicle speed. PCM uses this signal to calculate vehicle speed, shift timing and gear ratios. DTC sets when PCM detects a low vehicle speed with a high engine speed while in a drive range. DTC sets when PCM detects a large change in vehicle speed in a short period of time.

1. Engine speed is more than 500 RPM for 5 seconds and not in fuel shutoff.
2. Transmission is not in PARK or NEUTRAL.
3. Time since last range change is more than 6 seconds.
4. No output shaft speed rise greater than 250 RPM in 2 seconds.
5. DTCs P0502 and P1810 are not set.

DTC sets when output shaft speed drops greater than 1500 RPM in 3 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) during the second consecutive trip in which the Conditions for Setting DTC are met.
2. The PCM commands maximum line pressure.
3. The PCM freezes shift adapts.
4. The PCM calculates vehicle speed from the AT input shaft speed sensor for shift timing.
5. The PCM records the operating conditions when the Conditions for Setting DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
6. The PCM stores DTC P0503 in PCM history during the second consecutive trip in which the Conditions for Setting DTC are met.

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

The numbers below refer to the step numbers in the diagnostic procedures.

1. 3 This step test the ability of the VSS to produce an AC voltage. This step also verifies the integrity of the wiring to the PCM.
2. 4 This step test the VSS circuit for correct resistance.

1. Perform Diagnostic System Check - Engine Controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM. After performing Diagnostic System Check - Engine Controls, go to next step.
2. Install a scan tool. Turn ignition on, engine off. Record FREEZE FRAME/FAILURE RECORDS. Clear DTCs. Raise and support drive wheels. Start and idle engine. Place transmission in Drive. Monitor transmission VSS on scan tool. With drive wheels rotating, increase and decrease throttle position. Does VSS RPM increase when wheel speed increase? If yes, see «INTERMITTENT CONDITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__intermittent-conditions) under SELF-DIAGNOSTIC SYSTEM. If no, go to next step.
3. Turn off the ignition. Disconnect the PCM connector C1. Using the Connector Test Adapter Kit (J 35616-A), connect the DVOM between terminals C1-64 and C1-65 of the PCM harness connector. Select AC volts on the DVOM. Turn ignition on, with engine off. Place the range selector in a Drive range or Neutral. Rotate the right front drive wheel by hand, while observing the DVOM display. Does the voltage measure greater than 0.4 volts AC? If yes, go to step 8 . If no, go to next step.
4. Leave the DVOM test leads connected between terminals C1-64 and C1-65 of the PCM harness connector. Select ohms on the DVOM. Measure the resistance of the complete VSS circuit. Is the circuit resistance 1650-3180 ohms? If yes, go to step 9 . If no, go to next step.
5. Is the resistance more than 3180 ohms, go to step 11 . If no, go to next step.
6. Leave the DVOM test leads connected between terminals C1-64 and C1-65 of the PCM harness connector. Disconnect the VSS connector at the transmission. Test the high signal circuit (CKT 400) and the low signal circuit (CKT 401) of the VSS for a short together. Are the signal and ground circuits shorted together? If yes, go to next step. If no, go to step 14 .
7. Repair the short between the high signal circuit (CKT 400) and the low signal circuit (CKT 401). After repairs, go to step 16 .
8. Test the high signal circuit (CKT 400) of the VSS for a short to ground between the PCM and the VSS. Did you find and correct the condition? If yes, go to step 16 . If no, go to step 15 .
9. Reconnect PCM connector C1. Select DC volts on DVOM. Connect DVOM between terminals "A" and "B" of the VSS vehicle harness. Turn ignition on, with engine off. Does the DVOM display greater than 1.0 volts? If yes, go to next step. If no, go to step 13 .
10. Repair the short to power in the high signal circuit (CKT 400). After repairs, go to step 16 .
11. Test the high signal circuit (CKT 400) of the VSS for an open between the PCM and the VSS. Did you find and correct the condition? If yes, go to step 16 . If no, go to next step.
12. Test the low signal circuit (CKT 401) of the VSS for an open between the PCM and the VSS. Did you find and correct the condition? If yes, go to step 16 . If no, go to step 14 .
13. Remove VSS. Inspect VSS and transmission for the following: Incorrect VSS. VSS damage. Excessive runout in final drive carrier assembly. Excessive VSS to speed sensor rotor gap. Incorrect speed sensor rotor alignment. Speed sensor rotor damage. If problem was found, repair as necessary. See appropriate OVERHAUL article in AUTOMATIC TRANSMISSIONS. Did you find and correct the condition? If yes, go to step 16 . If no, go to next step.
14. Replace VSS. After repairs, go to step 16 .
15. Replace PCM. Program replacement PCM. See «POWERTRAIN CONTROL MODULE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under PROGRAMMING. After repairs, go to next step.
16. To verify repair, select DTC. Select CLEAR INFO. Drive vehicle. Ensure transmission VSS is more than 250 RPM for at least 2 seconds. Select SPECIFIC DTC. Enter DTC P0502. If test has run and passed, system is okay. If test did not rum and pass, go to step 2 .

DTC P0506: IAC SYSTEM RPM LOW

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

The engine idle speed is controlled by the Idle Air Control (IAC) valve. The IAC valve is on the throttle body. The IAC valve pintle moves in and out of an idle air passage bore to control airflow around the throttle plate. The valve consists of a movable pintle, driven by a gear attached to a two phase bi-polar permanent magnet electric motor called a stepper motor. The stepper motor is capable of highly accurate rotation, or of movement, called steps. The stepper motor has two separate windings that are called coils. Each coil is fed by two circuits from the Powertrain Control Module (PCM). When the PCM changes polarity of a coil, the stepper motor moves one step. The PCM uses a predetermined number of counts to determine the IAC pintle position. Observe IAC counts with a scan tool. The IAC counts will increment up or down as the PCM attempts to change the IAC valve pintle position. An IAC Reset will occur when the ignition key is turned off. First, the PCM will seat the IAC pintle in the idle air passage bore. Second, the PCM will retract the pintle a predetermined number of counts to allow for efficient engine start-up. If the engine idle speed is out of range for a calibrated period of time, an idle speed DTC may set.

1. DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0171, P0172, P0201, P0202, P0203, P0204, P0205, P0206, P0300, P0401, P0403, P0404, P0405, and P0502 are not set.
2. Engine run time is more than 2 minutes.
3. ECT is more than 158°F (70°C).
4. IAT is more than -0.4°F (-18°C).
5. BARO is more than 70 kPa.
6. Ignition voltage is 9-18 volts.
7. VSS is less than 3 MPH.
8. TPS is less than 1.3 percent.
9. Conditions are present for 8 seconds

1. The actual engine speed is 100 RPM less than the desired engine speed for more than 8 seconds for each test.
2. The PCM detects the IAC test failed 5 consecutive times per ignition cycle.
3. The vehicle must enter this criteria and then leave the criteria for one second in order to complete one IAC test.

1. The control module illuminates the Malfunction Indicator Light (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 Light (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.

Inspect for the following conditions

1. High resistance in an IAC circuit.
2. Restricted air intake system.
3. Proper operation and installation of all air intake components.
4. Collapsed, clogged, or loosed air intake ducts.
5. A clogged air filter.
6. Proper operating of the Mass Airflow (MAF) sensor, if equipped.
7. A tampered with or damaged throttle stop screw.
8. A tampered with or damaged throttle plate, throttle shaft, or throttle linkage.
9. Objects blocking the IAC passage or throttle bore.
10. Excessive deposits in the throttle bore or on the throttle plate.
11. Vacuum leaks.
12. A low or unstable idle condition could be caused by a non-IAC system problem that can not be overcome by the IAC valve.

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

The numbers below refer to the step numbers in the diagnostic procedures.

1. 5 This test will determine the ability of the engine controller and IAC valve control circuits to control the IAC valve.
2. 7 This test will determine the ability of the PCM to provide the IAC valve control circuits with a ground. On a normal operating system, the test light should not flash while the IAC counts are incrementing.

Scheme 354

Scheme 355

Scheme 356

DTC P0507: IAC SYSTEM RPM HIGH

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

The engine idle speed is controlled by the Idle Air Control (IAC) valve. The IAC valve is on the throttle body. The IAC valve pintle moves in and out of an idle air passage bore to control air flow around the throttle plate. The IAC valve consists of a movable pintle, driven by a gear attached to an electric motor called a stepper motor. The stepper motor is capable of highly accurate rotation, or of movement, called steps. The stepper motor has 2 separate windings that are called coils. Each coil is supplied current by two circuits from the Powertrain Control Module (PCM). When the PCM changes polarity of a coil, the stepper motor moves one step. The PCM uses a predetermined number of counts to determine the IAC pintle position. Observe IAC counts with a scan tool. The IAC counts will increment up or down as the PCM attempts to change the IAC valve pintle position. An IAC Reset will occur when the ignition key is turned OFF. First, the PCM will seat the IAC pintle in the idle air passage bore. Second, the PCM will retract the pintle a predetermined number of counts to allow for efficient engine start-up. If the engine idle speed is out of range for a calibrated period of time, an idle speed Diagnostic Trouble Code (DTC) sets.

1. DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0171, P0172, P0201-P0206, P0300, P0401, P0403, P0404, P0405, and P0502 are not set.
2. Engine run time is more than 2 minutes.
3. ECT is more than 158°F (70°C).
4. IAT is more than -0.4°F (-18°C).
5. BARO is more than 70 kPa.
6. Ignition voltage is 9-18 volts.
7. VSS is less than 3 MPH.
8. TPS is less than 1.3 percent.
9. Conditions are present for 8 seconds.

1. The actual engine speed is 175 RPM more than the desired idle speed for more than 8 seconds for each test.
2. The PCM detects the IAC test failed 5 consecutive times per ignition cycle.
3. The vehicle must enter this criteria and leave the criteria for 1 second in order to complete one test.

1. The control module illuminates the Malfunction Indicator Light (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 Light (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.

Inspect for the following conditions

1. High resistance in an IAC circuit.
2. Correct PCV valve, properly installed, and properly operating.
3. Proper operation and installation of all air intake components.
4. Proper installation and operation of Mass Airflow (MAF) sensor, if equipped.
5. Tampered or damaged throttle stop screw.
6. Tampered or damaged throttle plate, throttle shaft, throttle linkage, or cruise control linkage, if equipped.
7. Skewed high TP sensor.
8. Excessive deposits in IAC passage or on IAC pintle.
9. Excessive deposits in throttle bore or on throttle plate.
10. Vacuum leaks.
11. High or unstable idle condition could be caused by a non-IAC system problem that cannot be overcome by IAC valve.

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

The numbers below refer to the step numbers in the diagnostic procedures.

1. 5 This test will determine the ability of the engine controller and IAC valve circuits to control the IAC valve.
2. 7 This test will determine the ability of the PCM to provide the IAC valve circuits with a ground. On a normally operating system, the test light should not flash while the IAC counts are incrementing.

Scheme 357

Scheme 358

Scheme 359

DTC P0560: SYSTEM VOLTAGE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

PCM monitors system voltage to make sure voltage stays within proper range. Damage to components, and incorrect data input can occur when voltage is out of range. PCM monitors system voltage over an extended length of time. DTC sets when PCM detects a system voltage outside an expected range for calibrated length of time.

1. System voltage less than 9 volts or more than 16 volts.
2. Engine speed more than 1500 RPM.
3. Vehicle speed less than 25 MPH.

DTC sets when system voltage monitored at the PCM ignition feed circuit is less than 9 volts or more than 16 volts for more than 25 seconds.

1. The PCM will not illuminate the Malfunction Indicator Light (MIL).
2. The PCM will command a message to be displayed.
3. The PCM will store conditions which were present when the DTC set as Fail Records data only.

1. The PCM will command the message off after one trip in which the diagnostic test has been run and passed.
2. The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
3. The DTC can be cleared by using the scan tool Clear DTC Information function.

1. Perform Diagnostic System Check - Engine Controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM. After performing Diagnostic System Check - Engine Controls, go to next step.
2. Install a scan tool. Operate the vehicle within the Conditions for Running DTC. Using the scan tool, observe the Specific DTC Information for DTC P0560 until the test runs. Does the scan tool indicate that DTC P0560 has passed this ignition cycle? If yes, see «INTERMITTENT CONDITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__intermittent-conditions) under SELF-DIAGNOSTIC SYSTEM. If no, go to next step.
3. Leave the engine running. With a scan tool, observe the IGNITION 1 SIGNAL parameter in the PCM data list. Does the scan tool indicate that the IGNITION 1 SIGNAL parameter is 9-16 volts? If yes, go to step 6 . If no, go to next step.
4. Using a scan tool compare the BATTERY VOLTAGE parameter in the DIM data list with the IGNITION 1 SIGNAL parameter in the PCM data list. Are the DIM Battery Voltage and PCM Ignition 1 readings different by more than 0.5 volts? If yes, go to next step. If no, test charging system. See appropriate GENERATORS & REGULATORS article in ELECTRICAL.
5. Test the battery positive voltage circuit of the PCM for a high resistance. Did you find and correct the condition? If yes, go to step 8 . If no, go to next step.
6. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step 8 . If no, go to next step.
7. Replace PCM. Program replacement PCM. See «POWERTRAIN CONTROL MODULE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under PROGRAMMING. After repairs, go to next step.
8. Review and record scan tool FREEZE FRAME/FAILURE RECORDS data. Using scan tool, clear DTC. Operate vehicle within Conditions for Running DTC. Using scan tool, observe SPECIFIC DTC INFORMATION for DTC P0560 until test runs. Does scan tool indicate DTC P0560 failed this ignition cycle? If yes, go to step 3 . If no, system is okay.

DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683 & P2610: PCM INTERNAL MICROPROCESSOR INTEGRITY

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

This diagnostic applies to internal microprocessor integrity conditions within PCM. This diagnostic also addresses if PCM is not programmed.

The numbers below refer to the step numbers in the diagnostic procedures.

1. 2 A DTC P0602 indicates the PCM is not programmed.

Scheme 360

DTC P0620: GENERATOR PERFORMANCE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Powertrain Control Module (PCM) uses generator turn on signal circuit to control generator. A high side driver within PCM allows PCM to turn generator on and off. When generator operation is desired, PCM sends a 5-volt signal to voltage regulator via generator turn on signal circuit. This causes voltage regulator to begin controlling generator field circuit. Once generator is enabled by PCM, voltage regulator controls generator output independently of PCM. Under certain operating conditions, PCM can turn off generator by turning off 5-volt signal on generator turn on signal circuit. PCM has fault detection circuitry which monitors state of generator turn on signal circuit. DTC sets when fault detection circuit senses a voltage other than what is expected. Voltage regulator also contains fault detection circuitry. If regulator detects a problem, regulator will ground generator turn on signal circuit, pulling voltage low. This also causes PCM to set the DTC.

PCM receives generator output feedback via generator field duty cycle signal circuit. Voltage regulator generates a PWM signal on field control circuit. Regulator varies pulse width of this signal in order to control generator output. This signal is also sent to PCM via generator field duty cycle signal circuit. Pulse width of signal is proportional to generator output. PCM expects generator output to be within a predetermined range under certain operating conditions. DTC sets when PCM detects PWM signal on generator field duty cycle signal circuit is not within expected range. When this DTC sets, the PCM sends a class 2 serial data message to the Instrument Panel (IP) illuminating the charge indicator light.

1. Engine is running.

DTC sets when generator turn on signal circuit voltage is low while PCM is commanding generator on for more than 30 seconds; or when generator field duty cycle signal PWM is less than 5 percent and engine RPM is less than 2500 for more than 30 seconds.

1. The PCM stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Light (MIL) will not illuminate.
3. The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records.

1. A History DTC will clear after forty consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
2. The current DTC will clear when the diagnostic runs and does not fail.

1. Perform Diagnostic System Check - Engine Controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM. After performing Diagnostic System Check - Engine Controls, go to next step.
2. Install scan tool. Start engine. Using scan tool, observe GENERATOR PWM parameter in PCM data list. Does the scan tool indicate GENERATOR PWM parameter is 5-95 percent? If yes, go to next step. If no, go to step 4 .
3. Using scan tool, command generator off. Does the GENERATOR PWM equal zero percent? If yes, see «INTERMITTENT CONDITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__intermittent-conditions) under SELF-DIAGNOSTIC SYSTEM. If no, go to next step.
4. Turn ignition off. Disconnect generator harness connector. Start engine. Measure the voltage between the generator turn on signal circuit and a known-good ground. With the scan tool command the generator on and off. Is the voltage equal to zero volts with the generator off and equal to 5 volts with the generator on? If yes, go to next step. If no, go to step 6 .
5. Turn ignition on, engine off. Using a test light connected to battery voltage, repeatedly probe the generator field duty cycle signal circuit in the harness connector while monitoring the GENERATOR PWM on scan tool. Is the GENERATOR PWM display is affected? If yes, go to step 8 . If no, go to step 7 .
6. Test the generator turn on signal circuit for a short or open. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 9 .
7. Test the generator field duty cycle signal circuit for a short or open. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 9 .
8. Inspect for poor connections at the harness connector of the generator. Did you find and correct the condition? If yes, go to step 11 . If no, see appropriate GENERATORS & REGULATORS article in ELECTRICAL.
9. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step 11 . If no, go to next step.
10. Replace PCM. Program replacement PCM. See «POWERTRAIN CONTROL MODULE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under PROGRAMMING. After repairs, go to next step.
11. Review and record scan tool FREEZE FRAME/FAILURE RECORDS data. Clear any DTCs. Operate vehicle within Conditions for Running DTC. Using scan tool, monitor SPECIFIC DTC INFO for this DTC. Does the scan tool indicate this DTC failed this ignition cycle? If yes, go to step 2 . If no, system is okay.

DTC P0650: MALFUNCTION INDICATOR LIGHT CONTROL CIRCUIT

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

The Malfunction Indicator Light (MIL) is located on the Instrument Panel Cluster (IPC). The MIL informs the driver than 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. For example, a failure conditions exists if the control module detects low voltage when the MIL is commanded OFF, or high voltage when the MIL is commanded ON. If the control module detects an improper voltage on the MIL control circuit, DTC P0650 will set.

Ignition is on.

The control module detects that the commanded state of the MIL driver and the actual state of the control module do not match. The conditions are present for a minimum of 30 seconds.

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 seconds 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 Light (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 in the diagnostic procedures.

1. 5 This step tests for a short to ground in the MIL control circuit. With the Powertrain Control Module (PCM) disconnected and the ignition ON, the MIL should be OFF.
2. 6 This step tests for a short to voltage on the MIL control circuit. With the fuse removed, there should be no voltage on the MIL control circuit.

Scheme 361

Scheme 362

DTC P0719: TCC BRAKE SWITCH CIRCUIT - LOW INPUT

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

The TCC brake switch indicates brake pedal status to the PCM. The TCC brake switch indicates that the brake pedal is either applied or released. The normally-closed switch supplies battery voltage to the PCM. Applying the brake pedal opens the TCC brake switch, interrupting voltage to the PCM. When the PCM receives zero volts at the TCC brake switch input, the PCM turns off the Torque Converter Clutch Pulse Width Modulation (TCC PWM) solenoid valve. DTC P0719 sets when the PCM detects an open brake switch (indicating pedal applied) during a number of accelerations.

No VSS DTC P0502 or P0503.

The TCC brake switch indicates continuously open (0 volts) for more than 15 minutes and the following conditions occur 8 times consecutively.

1. The vehicle speed is less than 5 MPH.
2. Then the vehicle speed is 5-20 MPH for 3 seconds.
3. Finally, the vehicle speed remains above 20 MPH for 6 seconds.

1. The PCM does not illuminate the Malfunction Indicator Light (MIL).
2. The PCM disregards the TCC brake switch for TCC scheduling when all of the following conditions are met: The TP angle is greater than 6 percent. The vehicle speed is greater than 37 MPH. The TP angle was previously greater than 12 percent while the vehicle speed was greater than 42 MPH. The TCC brake switch has not indicated off for more than 2 seconds this trip.
3. The PCM records the operating conditions when the Conditions For Setting DTC are met. The PCM stores this information as Failure Records.
4. The PCM stores DTC P0719 in PCM history.

1. A scan tool can clear the DTC.
2. The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-emission-related diagnostic fault occurring.
3. The PCM cancels the DTC default actions when the fault no longer exists and the DTC passes.

The numbers below refer to the step numbers in the diagnostic procedures.

1. 6 This step isolates the fault between the TCC brake switch and the harness.

1. Perform Diagnostic System Check - Engine Controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM. After performing Diagnostic System Check - Engine Controls, go to next step.
2. Install a scan tool. Turn ignition on, with engine off. Record the Failure Records. Clear the DTCs. With a scan tool, observe the TCC BRAKE SWITCH parameter. Does the scan tool display CLOSED? If yes, see «INTERMITTENT CONDITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__intermittent-conditions) under SELF-DIAGNOSTIC SYSTEM. If no, go to next step.
3. Remove the fuse from the ignition 1 voltage circuit. Inspect the fuse for an open. Replace the fuse if necessary. Was the fuse open? If yes, go to next step. If no, go to step 5 .
4. Test the ignition 1 voltage circuit (CKT 239) of the TCC brake switch for a short to ground between the fuse block and the brake switch. Test the signal circuit (CKT 420) of the TCC brake switch for a short to ground between the PCM and the TCC brake switch. Repair as necessary. After repairs, go to step 10 .
5. Disconnect the TCC brake switch 4-way connector. Connect a fused jumper wire from terminal "A" to terminal "B" of the TCC brake switch connector. Turn ignition on, with engine off. With a scan tool, observe the TCC BRAKE SWITCH parameter. Does the scan tool display CLOSED? If yes, go to step 8 . If no, go to next step.
6. Test the ignition 1 voltage circuit (CKT 239) of the TCC brake switch for an open between the fuse block and the brake switch. Did you find and correct the condition? If yes, go to step 10 . If no, go to next step.
7. Test the signal circuit (CKT 420) of the TCC brake switch for an open between the PCM and the brake switch. Did you find and correct the condition? If yes, go to step 10 . If no, go to step 9 .
8. Replace the TCC brake switch. After repairs, go to step 10 .
9. Replace PCM. Program replacement PCM. See «POWERTRAIN CONTROL MODULE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under PROGRAMMING. After repairs, go to next step.
10. Perform the following procedure in order to verify the repair: Select DTC. Select CLEAR INFO. Turn ignition on, with engine off. The TCC brake switch must be closed (pedal released) for more than 2 seconds. Select SPECIFIC DTC. Enter DTC P0719. Has the test run and passed? If yes, system is okay. If no, go to step 1 .

DTC P0724: TCC BRAKE SWITCH CIRCUIT - HIGH INPUT

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

The TCC brake switch indicates brake pedal status to the PCM. The TCC brake switch indicates that the brake pedal is either applied or released. The normally-closed switch supplies battery voltage to the PCM. Applying the brake pedal opens the TCC brake switch, interrupting voltage to the PCM. When the PCM receives 0 volts at the TCC brake switch input, the PCM turns OFF the torque converter clutch pulse width modulation (TCC PWM) solenoid valve. If the PCM detects a closed TCC brake switch (indicating pedal released) during a number of decelerations, then DTC P0724 sets.

No VSS DTC P0502 or P0503.

The TCC brake switch indicates continuously CLOSED (12 volts) while the following conditions occur 8 times consecutively

1. The vehicle speed is greater than 20 MPH for 6 seconds.
2. Then the vehicle speed decreases to 5 MPH and takes 3 seconds.
3. Finally, the vehicle speed is less than 5 MPH.

1. The PCM does not illuminate the Malfunction Indicator Light (MIL).
2. The PCM records the operating conditions when the Conditions For Setting DTC are met. The PCM stores this information as Failure Records.
3. The PCM stores DTC P0724 in PCM history.

1. A scan tool can clear the DTC.
2. The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-emission-related diagnostic fault occurring.
3. The PCM cancels the DTC default actions when the fault no longer exists and the DTC passes.

The numbers below refer to the step numbers in the diagnostic procedures.

1. 3 If the scan tool indicates CLOSED in step 2 , and OPEN when the TCC brake switch is disconnected, the switch is stuck closed.

1. Perform Diagnostic System Check - Engine Controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM. After performing Diagnostic System Check - Engine Controls, go to next step.
2. Install a scan tool. Turn ignition on, with engine off. Record the Failure Records. Clear the DTCs. With a scan tool, observe the TCC BRAKE SWITCH parameter. Apply the brake pedal. Does the scan tool display OPEN? If yes, see «INTERMITTENT CONDITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__intermittent-conditions) under SELF-DIAGNOSTIC SYSTEM. If no, go to next step.
3. Turn off the ignition. Disconnect the TCC brake switch 4-way connector. Turn ignition on, with engine off. With a scan tool, observe the TCC BRAKE SWITCH parameter. Does the scan tool display OPEN? If yes, go to step 5 . If no, go to next step.
4. Test the signal circuit (CKT 420) of the TCC brake switch for a short to power between the PCM and the TCC brake switch. Did you find and correct the condition? If yes, go to step 7 . If no, go to step 6 .
5. Replace the TCC brake switch. After repairs, go to step 7 .
6. Replace PCM. Program replacement PCM. See «POWERTRAIN CONTROL MODULE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under PROGRAMMING. After repairs, go to next step.
7. Perform the following procedure in order to verify the repair: Select DTC. Select CLEAR INFO. Turn ignition on, with engine off. Apply brake pedal. The TCC brake switch must be open for more than 2 seconds. Select SPECIFIC DTC. Enter DTC P0724. Has the test run and passed? If yes, system is okay. If no, go to step 1 .

DTC P1106: MAP SENSOR CIRCUIT INTERMITTENT - HIGH VOLTAGE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

1. VIN K The Manifold Absolute Pressure (MAP) sensor responds to changes in intake manifold pressure which gives an indication of the engine load. The MAP sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. The Powertrain Control Module (PCM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit and provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the MAP sensor signal circuit which is relative to the pressure changes in the manifold. With low MAP such as during idle or deceleration, the PCM should detect a low MAP sensor signal voltage. With high MAP such as ignition ON, engine OFF or wide open throttle (WOT), the PCM should detect a high MAP sensor signal voltage. This MAP sensor will indicate pressure between 10-104 kPa. The MAP sensor is also used in order to calculate the Barometric Pressure (BARO) when the ignition switch is turned ON, with the engine OFF. The BARO reading may also be updated whenever the engine is operated at wide open throttle. The PCM monitors the MAP sensor signal for voltage outside of the normal range. If the PCM detects a MAP sensor signal voltage that is intermittently high, DTC P1106 sets.
2. VIN 1 The MAP sensor responds to changes in intake manifold pressure which gives an indication of the engine load. The MAP sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. The PCM supplies 5 volts to the MAP sensor on the 5-volt reference circuit and provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the MAP sensor signal circuit which is relative to the pressure changes in the manifold. With low MAP such as during idle or deceleration, the PCM should detect a low MAP sensor signal voltage. With high MAP such as WOT, the PCM should detect a high MAP sensor signal voltage. This MAP sensor will indicate pressure between 8-208 kPa. The MAP sensor is also used in order to calculate the BARO when the ignition switch is turned ON, with engine OFF. The PCM monitors the MAP sensor signal for voltage outside of the normal range. If the PCM detects a MAP sensor signal voltage that is intermittently high, DTC P1106 sets.

1. VIN K DTCs P0121, P0122, or P0123 are not set. Engine has been running for a period of time that is determined by start-up coolant temperature. Time ranges from 2 minutes at less than -22°F (-30°C) to one second at more than 86°F (30°C). Throttle angle is less than 2 percent when engine speed is less than 1500 RPM. Throttle angle is less than 10 percent when engine speed is more than 1500 RPM.
2. VIN 1 DTCs P0121, P0122, or P0123 are not set. Engine has been running for a length of time that is determined by start-up coolant temperature. Length of time ranges from 2 minutes at less than -22°F (-30°C) to one second at more than 86°F (30°C). Throttle angle is less than 2 percent when engine speed is less than 900 RPM. Throttle angle is less than 30 percent when engine speed is more than 900 RPM.

DTC sets when MAP sensor signal voltage is more than 4.2 volts for 20 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Light (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.

The numbers below refer to the step numbers in the diagnostic procedures.

1. 3 Many intermittent open or shorted circuits come and go with harness and connector movement caused by vibration, engine torque, and bumps. This step attempts to recreate the fault which set the DTC.

Scheme 363

DTC P1107: MAP SENSOR CIRCUIT INTERMITTENT - LOW VOLTAGE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

1. VIN K The Manifold Absolute Pressure (MAP) sensor responds to changes in the intake manifold pressure, which gives an indication of the engine load. The MAP sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. The Powertrain Control Module (PCM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit and provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the MAP sensor signal circuit, which is relative to the pressure changes in the manifold. With low MAP such as during idle or deceleration, the PCM should detect a low MAP sensor signal voltage. With high MAP such as ignition ON, engine OFF, or Wide-Open Throttle (WOT), the PCM should detect a high MAP sensor signal voltage. This MAP sensor will indicate pressure between 10-104 kPa. The MAP sensor is also used in order to calculate the Barometric Pressure (BARO) when the ignition switch is turned ON, with the engine OFF. The BARO reading may also be updated whenever the engine is operated at WOT. The PCM monitors the MAP sensor signal for voltage outside of the normal range. If the PCM detects a MAP sensor signal voltage that is intermittently low, DTC P1107 sets.
2. VIN 1 The MAP sensor responds to changes in intake manifold pressure which gives an indication of the engine load. The MAP sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. The PCM supplies 5 volts to the MAP sensor on the 5-volt reference circuit, and provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the MAP sensor signal circuit which is relative to the pressure changes in the manifold. With low MAP such as during idle or deceleration, the PCM should detect a low MAP sensor signal voltage. With high MAP such as WOT, the PCM should detect a high MAP sensor signal voltage. This MAP sensor will indicate pressure between 8-208 kPa. The MAP sensor is also used in order to calculate the BARO when the ignition switch is turned ON, with the engine OFF. The PCM monitors the MAP sensor signal for voltage outside of the normal range. If the PCM detects a MAP sensor signal voltage that is intermittently low DTC P1107 sets.

1. DTCs P0121, P0122, or P0123 are not set.
2. Ignition is on.
3. Throttle angle is more than zero percent when engine speed is less than 1000 RPM.
4. Throttle angle is more than 10 percent when engine speed is more than 1000 RPM.

DTC sets when MAP sensor signal voltage is less than 0.1 volt for more than 20 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Light (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.

The number below refers to the step number in the diagnostic procedures.

1. 3 Many intermittent open or shorted circuits come and go with harness and connector movement caused by vibration, engine torque, and bumps. This step attempts to recreate the fault which set the DTC.

Scheme 364

DTC P1112: IAT SENSOR CIRCUIT INTERMITTENT - LOW VOLTAGE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

The Intake Air Temperature (IAT) sensor is a variable resistor. The IAT sensor has a signal circuit and a low reference circuit. The IAT sensor measures the temperature of the air entering the engine. The Powertrain Control Module (PCM) supplies 5 volts to the IAT signal circuit. When the IAT sensor is cold, the sensor resistance is high. When the air temperature increases, the sensor resistance decreases. With high sensor resistance, the PCM detects a high voltage on the IAT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the IAT signal circuit. DTC will set when PCM detects an intermittently low signal voltage on IAT sensor signal circuit.

1. DTCs P0101, P0102, P0103, P0116, P0117, P0118, P0502, or P0503 are not set.
2. Engine has been running for over 10 seconds.
3. Vehicle speed is more than 25 MPH.

DTC sets when IAT is more than 253°F (123°C) for 20 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Light (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.

Scheme 365

DTC P1114: ECT SENSOR CIRCUIT INTERMITTENT - LOW VOLTAGE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Engine Coolant Temperature (ECT) sensor is a variable resistor, sometimes called a thermistor, that measures temperature of engine coolant. Powertrain Control Module (PCM) supplies 5 volts to ECT signal circuit. When ECT is cold, sensor resistance is high. When ECT increases, sensor resistance lowers. With high sensor resistance, PCM detects a high voltage on ECT signal circuit. With lower sensor resistance, PCM detects a lower voltage on ECT signal circuit. DTC sets when PCM detects an excessively low ECT signal voltage, which is a high temperature indication.

1. Engine run time is more than 5 seconds.

DTC sets when PCM detects an intermittent high ECT sensor temperature while the engine is running and run time exceeds 5 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Light (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. An ECT sensor or PCM which is intermittently shorted, open, or skewed is possible yet very unlikely.
2. An intermittent short to ground in ECT sensor signal circuit could result in a DTC P1114. If the low ECT voltage, high temperature, reading is present, additional sensor circuit voltage DTCs could be set. Refer to any non-intermittent DTCs that are set, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) .
3. Test coolant sensor at various temperature levels to evaluate possibility of a skewed sensor. See «SENSOR TEMPERATURE VS. RESISTANCE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) . A skewed sensor could result in poor driveability complaints.
4. If an intermittent condition is suspected, see «INTERMITTENT CONDITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__intermittent-conditions) under SELF-DIAGNOSTIC SYSTEM.

Scheme 366

DTC P1115: ECT SENSOR CIRCUIT INTERMITTENT - HIGH VOLTAGE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For intermittent conditions, see INTERMITTENT CONDITIONS under SELF DIAGNOSTIC SYSTEM. If testing requires component removal or replacement, see appropriate REMOVAL & INSTALLATION article.

Engine Coolant Temperature (ECT) sensor is a variable resistor, sometimes called a thermistor, that measures temperature of engine coolant. Powertrain Control Module (PCM) supplies 5 volts to ECT signal circuit. When ECT is cold, sensor resistance is high. When ECT increases, sensor resistance lowers. With high sensor resistance, PCM detects a high voltage on ECT signal circuit. With lower sensor resistance, PCM detects a lower voltage on the ECT signal circuit. DTC sets when PCM detects an excessively high signal voltage, which is a low temperature indication.

1. Engine run time is more than 5 seconds.

The PCM detects an intermittent low EVT sensor temperature while the engine is running and the engine run time exceeds 5 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Light (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.