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Engine Controls - Basic Diagnostic Procedures - 3.8l Buick Park Avenue II рестайлинг

Testing & Diagnostics 2 illustrations ~14624 words

INTRODUCTION

Before proceeding with basic diagnostic procedures, ensure testing procedure is followed, as some systems which may result in a no-start condition may cause a Diagnostic Trouble Code (DTC) to be stored in the Powertrain Control Module (PCM). See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.

If no-start condition still exists after checking and repairing all DTCs, perform a careful and complete visual inspection. Many problems result from mechanical breakdowns, poor electrical connections or damaged/misrouted vacuum hoses. See VISUAL INSPECTION under PRELIMINARY INSPECTION & ADJUSTMENTS. Before condemning the computerized system, perform each test listed in this article.

CAUTIONWhen battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES - GENERAL MOTORS article in GENERAL INFORMATION before disconnecting battery.

Note. Perform all voltage tests using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure.

VISUAL INSPECTION

Visually inspect all electrical wiring, looking for chafed, stretched, cut or pinched wiring. Ensure harness connectors fit tightly and are not corroded. Ensure vacuum hoses are properly routed and not pinched or cut. If necessary, see appropriate VACUUM DIAGRAMS article to verify routing and connections. Check air induction system for possible vacuum leaks.

Cylinder Compression Pressure

A compression pressure test of the engine cylinders determines the condition of the rings, the valves, and the head gasket.

  1. Run the engine until it reaches normal operating temperature. The battery must be at or near full charge.
  2. Turn the engine OFF.
  3. Disable the ignition by removing the Powertrain Control Module (PCM) and the ignition fuses from the appropriate fuse block. See «PCM/ICM FUSE LOCATION»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l) table.
  4. Disable the fuel system. Remove fuel pump fuse. See «FUEL PUMP FUSE LOCATION»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l) table.
  5. Remove the spark plugs from all the cylinders.
  6. Remove the air duct from the throttle body.
  7. Block the throttle plate in the OPEN position.
  8. Measure the engine compression, using the following procedure: Firmly install Compression Tester (J 38722), or equivalent, to the spark plug hole. Have an assistant crank the engine through at least 4 compression strokes in the testing cylinder. Check and record the readings on the compression tester at each stroke. Disconnect the compression tester. Repeat the compression test for each cylinder.
  9. Record the compression readings from all of the cylinders. The lowest reading should not be less than 70 percent of the highest reading. No cylinder reading should be less than 100 psi (689 kPa).
  10. The following are examples of the possible measurements: When the compression measurement is normal, the compression builds up quickly and evenly to the specified compression on each cylinder. When the compression is low on the first stroke and tends to build up on the following strokes, but does not reach the normal compression, or if the compression improves considerably with the addition of 3 squirts of oil, the piston rings may be the cause. When the compression is low on the first stroke and does not build up in the following strokes, or the addition of oil does not affect the compression, the valves may be the cause. When the compression is low on 2 adjacent cylinders, or coolant is present in the crankcase, the head gasket may be the cause.
  11. Remove the block from the throttle plate.
  12. Install the air duct to the throttle body.
  13. Install the spark plugs.
  14. Install the PCM/ICM fuses removed.
  15. Install the fuel pump fuse removed.
ModelPCMICMLocation
BonnevillePCM BATT Fuse No. 8 (10-Amp)DIS Fuse No. 15 (20-Amp)Underhood Fuse Block
Grand PrixECM SENSE Fuse No. 33 (10-Amp)ELEK IGN Fuse No. 25 (15-Amp)Underhood Fuse Block
ImpalaPCM Fuse No. 19 (15-Amp)ICM DFI MDL Fuse No. 15 (15-Amp)(1) Underhood Fuse Block
LeSabrePCM IGN 1 Fuse No. 19 (10-Amp)DIS Fuse No. 14 (20-Amp)Underhood Fuse Block
Monte CarloPCM Fuse (15-Amp)ICM DFI MDL Fuse No. 15 (15-Amp)(1) (2) Underhood Fuse Block
Park AvenuePCM Fuse (10-Amp)C31 Fuse (10-Amp)Left Underhood Fuse Block
RegalPCM BCM IGN RELAY Fuse (10-Amp)ELEK IGN Fuse No. 26 (15-Amp)(3)
(1) ICM DFI MDL fuse No. 15 located in bottom underhood fuse block. (2) PCM fuse located in top underhood fuse block. (3) PCM fuse located in instrument panel fuse block, ICM fuse located in underhood fuse block.
(1)ICM DFI MDL fuse No. 15 located in bottom underhood fuse block.
(2)PCM fuse located in top underhood fuse block.
(3)PCM fuse located in instrument panel fuse block, ICM fuse located in underhood fuse block.

PCM/ICM FUSE LOCATION

ModelFuse IdentificationLocation
BonnevilleF/PMP Fuse No. 1 (20-Amp)Rear Fuse Block
Grand PrixFUEL PUMP Fuse No. 32 (15-Amp)Underhood Fuse Block
Impala & Monte CarloF/PMP RLY Fuse (15-Amp)Underhood Junction Block
LeSabreF/PMP Fuse No. 1 (20-Amp)Rear Fuse Block
Park AvenueF/PMP Fuse No. 1 (20-Amp)Left Underhood Fuse Block
RegalF/PMP Fuse No. 35 (15-Amp)Underhood Fuse Block

FUEL PUMP FUSE LOCATION

Cylinder Leakage

WARNINGBefore servicing any electrical component, the ignition key must be in the OFF or LOCK position and all electrical loads must be OFF, unless instructed otherwise in these procedures. If a tool or equipment could easily come in contact with a live exposed electrical terminal, also disconnect the negative battery cable. Failure to follow these precautions may cause personal injury and/or damage to the vehicle or its components.

With the use of air pressure, a cylinder leakage test will aid in the diagnosis. The cylinder leakage test may be used in conjunction with the engine compression test, to isolate the cause of leaking cylinders.

  1. Disconnect the negative battery cable.
  2. Remove the spark plugs.
  3. Install the Cylinder Head Leakdown Tester (J 35667-A), or equivalent.
  4. Measure each cylinder on the compression stroke, with both valves closed.
  5. Apply air pressure, using the cylinder head leakdown tester, following manufacturer's instructions. It may be necessary to hold the crankshaft balancer bolt, to prevent piston movement.
  6. Record the cylinder leakage readings for each cylinder. Normal cylinder leakage is from 12-18 percent. Make a note of any cylinder with more leakage than the other cylinders. Any cylinder with 30 percent leakage or more requires service.
  7. Check the 4 primary areas, to properly diagnose a leaking cylinder.
  8. If air is heard from the intake or exhaust system, perform the following procedures. See appropriate article in ENGINES: Remove the valve rocker arm cover of the suspect cylinder head. Ensure that both valves are closed. Check the cylinder head for a broken valve spring. Remove the suspect cylinder head and inspect.
  9. If air is heard from the crankcase system at the crankcase, oil filler tube, perform the following procedure. See appropriate article in ENGINES for procedures and inspection specifications: Remove the piston from the suspect cylinder. Check the piston and connecting rod assembly. Check the engine block.
  10. If bubbles are found in the radiator, perform the following procedure. See appropriate article in ENGINES for procedures and inspection specifications: Remove both cylinder heads and inspect. Check the engine block.
  11. Remove the cylinder head leakdown tester.
  12. Install the spark plugs.
  13. Connect the negative battery cable.

NO-START DIAGNOSIS

Note. For component location and connector terminal identification, see COMPONENT LOCATIONS and CONNECTOR IDENTIFICATION in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. For circuit identification, see WIRING DIAGRAMS .

Note. Some vehicles are equipped with anti-theft systems (VATS or PASS-Key®) which will not allow vehicle to be started if improper starting procedures or improperly coded ignition keys are used. Both fuel injection and cranking systems will be disabled. Loss of fuel enable signal from anti-theft decoder module should set a diagnostic trouble code in PCM memory.

Definition - No start is defined as engine cranks properly, but does not start. Engine may fire a few times. For diagnosis, perform appropriate ENGINE CRANKS BUT DOES NOT RUN diagnostic procedure.

ENGINE CRANKS BUT DOES NOT RUN (BONNEVILLE - VIN 1)

Note. For component location and connector terminal identification, see COMPONENT LOCATIONS and CONNECTOR IDENTIFICATION in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. For circuit identification, see WIRING DIAGRAMS .

Description

The Engine Cranks But Does Not Run diagnostic procedure is an organized approach to identifying a condition that causes an engine not to start. The Engine Cranks But Does Not Run diagnostic procedure directs the service technician to the appropriate system diagnosis and assumes that the battery is completely charged, the engine cranking speed is acceptable and there is adequate fuel in the fuel tank.

  1. If diagnostic system check has already been performed, go to next step. If diagnostic system check has not been performed, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  2. Turn ignition switch to RUN position, engine OFF. Observe the DTC information using a scan tool. Does the scan tool display DTC P0101, P0123, P0230, P0336, P0601, P0602 P1626, P1629, P1631 or P1683? If yes, diagnose affected DTCs. Go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, go to next step.
  3. Attempt to start the engine. Observe the engine speed parameter while the engine is cranking using a scan tool. Does the engine speed parameter display cranking RPM? If yes, go to next step. If no, go to «ELECTRONIC IGNITION SYSTEM DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__electronic-ignition-system-diagnosis) under IGNITION SYSTEMS.
  4. Command the fuel pump ON, using a scan tool. Does the fuel pump turn ON? If yes, go to next step. If no, go to «FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS (EXCEPT PARK AVENUE)»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__fuel-pump-electrical-circuit-diagnosis-except) under FUEL SYSTEMS.
  5. Turn ignition switch to OFF position. Disconnect a spark plug wire. Install the Spark Tester (J 26792), or equivalent, to the spark plug wire. Attempt to start the engine. Does the spark tester spark? If yes, go to next step. If no, go to «ELECTRONIC IGNITION SYSTEM DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__electronic-ignition-system-diagnosis) under IGNITION SYSTEMS.
  6. Turn ignition switch to OFF position. Install Fuel Pressure Gauge (J 34730-1A), or equivalent. (Scheme 407) Turn ignition switch to RUN position, engine OFF. Command the fuel pump ON using a scan tool. Is the fuel pressure 48-54 psi (336-375 kPa) while the fuel pump is operating? If yes, go to next step. If no, go to «FUEL SYSTEM DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__fuel-system-diagnosis) under FUEL SYSTEMS.
  7. Check for the following conditions: Collapsed air intake duct. Restricted air filter element. Spark plugs for being gas or coolant fouled. If the spark plugs are fouled, determine what caused the condition. Engine mechanical condition (worn timing chain and gears, low compression, etc.). See appropriate article in ENGINES. Restricted exhaust system. See «RESTRICTED EXHAUST»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. Faulty Engine Coolant Temperature (ECT) sensor. See «ENGINE COOLANT TEMPERATURE SENSOR»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l__engine-coolant-temperature-sensor) under SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. Faulty Manifold Absolute Pressure (MAP) sensor. See «MANIFOLD ABSOLUTE PRESSURE SENSOR»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l) under SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. Stuck Throttle Position (TP) sensor. See «DTC P0121: TP SENSOR PERFORMANCE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__dtc-p0121-tp-sensor-performance) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. After completing the action, go to next step.
  8. Clear the DTCs using a scan tool. Attempt to start the engine. Does the engine start and continue to operate? If yes, go to next step. If no, go to step 2.
  9. Idle the engine. Allow the engine to reach operating temperature. Observe the DTC information using a scan tool. Are any DTCs displayed? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, system is okay at this time.

ENGINE CRANKS BUT DOES NOT RUN (BONNEVILLE, LESABRE & PARK AVENUE - VIN K)

Note. For component location and connector terminal identification, see COMPONENT LOCATIONS and CONNECTOR IDENTIFICATION in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. For circuit identification, see WIRING DIAGRAMS .

The Engine Cranks But Does Not Run diagnostic procedure is an organized approach to identifying a condition that causes an engine not to start. The Engine Cranks But Does Not Run diagnostic procedure directs the service technician to the appropriate system diagnosis and assumes that the battery is completely charged, the engine cranking speed is acceptable and there is adequate fuel in the fuel tank.

  1. If diagnostic system check has already been performed, go to next step. If diagnostic system check has not been performed, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  2. Turn ignition switch to RUN position, engine off. Observe DTC information using a scan tool. Is DTC P0101, P0123, P0230, P0336, P0341, P0601, P0602, P1626, P1629, P1631 or P2610 set? If yes, diagnose affected DTC(s). See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, go to next step.
  3. Attempt to start the engine. Observe the engine speed parameter using a scan tool, while the engine is cranking. Does the engine speed parameter display cranking RPM? If yes, go to next step. If no, go to «ELECTRONIC IGNITION SYSTEM DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__electronic-ignition-system-diagnosis) under IGNITION SYSTEMS.
  4. Command the fuel pump relay ON using a scan tool. Does the fuel pump turn ON? On all models, if yes, go to next step. On Bonneville and LeSabre, if no, go to «FUEL SYSTEM DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__fuel-system-diagnosis). On Park Avenue, if no, go to «FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS (PARK AVENUE)»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__fuel-pump-electrical-circuit-diagnosis-park) under FUEL SYSTEMS.
  5. Turn ignition switch to OFF position. Disconnect a spark plug wire. Install the Spark Tester (J 26792), or equivalent, to the spark plug wire. Attempt to start the engine. Does the spark tester spark? If yes, go to next step. If no, go to «ELECTRONIC IGNITION SYSTEM DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__electronic-ignition-system-diagnosis) under IGNITION SYSTEMS.
  6. Turn ignition switch to OFF position. Disconnect a fuel injector harness connector. Install Fuel Injector Test Light (J 34730-405), or equivalent, to the fuel injector harness connector. Attempt to start the engine. Does the test light blink while the engine is cranking? If yes, go to next step. On Bonneville and LeSabre, if no, go to «DTC P0341: CAMSHAFT POSITION SENSOR PERFORMANCE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__dtc-p0341-camshaft-position-sensor-performance) in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. On Park Avenue, go to «FUEL INJECTOR CIRCUIT DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__fuel-injector-circuit-diagnosis) under FUEL SYSTEMS.
  7. Turn ignition switch to OFF position. Install Fuel Pressure Gauge (J 34730-1A), or equivalent. (Scheme 407) Turn ignition switch to RUN position, engine OFF. Command the fuel pump relay ON using a scan tool. On Bonneville and LeSabre, is the fuel pressure 48-54 psi (334-375 kPa) or, on Park Avenue, is the fuel pressure 53-59 psi (364-405 kPa), while the fuel pump is operating? If yes, go to next step. If no, go to «FUEL SYSTEM DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__fuel-system-diagnosis) under FUEL SYSTEMS.
  8. Check for the following conditions: Collapsed air intake duct. Restricted air filter element. Fouled spark plugs. If the spark plugs are fouled, determine what caused the condition. Engine mechanical condition (worn timing chain and gears, low compression, etc.). See appropriate article in ENGINES. Restricted exhaust system. See «RESTRICTED EXHAUST»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. Faulty Engine Coolant Temperature (ECT) sensor. See «ENGINE COOLANT TEMPERATURE SENSOR»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l__engine-coolant-temperature-sensor) under SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. Faulty Manifold Absolute Pressure (MAP) sensor. See «MANIFOLD ABSOLUTE PRESSURE SENSOR»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l) under SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. Stuck Throttle Position (TP) sensor. See «DTC P0121: TP SENSOR PERFORMANCE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__dtc-p0121-tp-sensor-performance) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. After completing the actions, go to next step.
  9. Clear the DTCs using a scan tool. Attempt to start the engine. Does the engine start and continue to operate? If yes, go to next step. If no, go to step 2.
  10. Idle the engine. Allow the engine to reach operating temperature. Observe the DTC information using a scan tool. Are any DTCs displayed? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, system is okay at this time.

ENGINE CRANKS BUT DOES NOT RUN (GRAND PRIX & REGAL - VIN 1)

Note. For component location and connector terminal identification, see COMPONENT LOCATIONS and CONNECTOR IDENTIFICATION in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. For circuit identification, see WIRING DIAGRAMS .

The Engine Cranks But Does Not Run diagnostic procedure is an organized approach to identifying a condition that causes an engine not to start. The Engine Cranks But Does Not Run diagnostic procedure directs the service technician to the appropriate system diagnosis and assumes that the battery is completely charged, the engine cranking speed is acceptable and there is adequate fuel in the fuel tank.

  1. If diagnostic system check has already been performed, go to next step. If diagnostic system check has not been performed, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  2. Turn ignition switch to RUN position, engine OFF. Observe the DTC information using a scan tool. Does the scan tool display DTC P0101, P0123, P0230, P0336, P0601, P0602, P1626, P1631 or P2610? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, go to next step.
  3. Turn ignition switch to RUN position, engine OFF. Probe both sides of the INJ fuse and the ELEK fuse using a test light connected to a good ground. Does the test light illuminate on at least one side of each fuse? If yes, go to next step. If no, go to «IGNITION RELAY DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__ignition-relay-diagnosis) under IGNITION SYSTEMS.
  4. Attempt to start the engine. Observe the engine speed parameter while the engine is cranking using a scan tool. Does the engine speed parameter display cranking RPM? If yes, go to next step. If no, go to «ELECTRONIC IGNITION SYSTEM DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__electronic-ignition-system-diagnosis) under IGNITION SYSTEMS.
  5. Command the fuel pump ON, using a scan tool. Does the fuel pump turn ON? If yes, go to next step. If no, go to «FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS (EXCEPT PARK AVENUE)»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__fuel-pump-electrical-circuit-diagnosis-except) under FUEL SYSTEMS.
  6. Turn ignition switch to OFF position. Disconnect a spark plug wire. Install the Spark Tester (J 26792), or equivalent, to the spark plug wire. Attempt to start the engine. Does the spark tester spark? If yes, go to next step. If no, go to «ELECTRONIC IGNITION SYSTEM DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__electronic-ignition-system-diagnosis) under IGNITION SYSTEMS.
  7. Turn ignition switch to OFF position. Disconnect an injector connector. Install TBI Harness Test Light (J 34730-2C), or equivalent, to the injector connector. Attempt to start the engine. Does the test light blink while the engine is cranking? If yes, go to next step. If no, go to «FUEL INJECTOR CIRCUIT DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__fuel-injector-circuit-diagnosis) under FUEL SYSTEMS.
  8. Turn ignition switch to OFF position. Connect Fuel Pressure Gauge (J 34730-1A), or equivalent, to the fuel pressure connection, located on the fuel rail. (Scheme 407) Turn ignition switch to RUN position, engine OFF. Command the fuel pump relay ON using a scan tool. Is the fuel pressure 48-54 psi (331-372 kPa) while the fuel pump is operating? If yes, go to next step. If no, go to «FUEL SYSTEM DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__fuel-system-diagnosis) under FUEL SYSTEMS.
  9. Check for the following conditions: Collapsed air intake duct. Restricted air filter element. Spark plugs for being gas or coolant fouled. If the spark plugs are fouled, determine what caused the condition. Repair as necessary. Engine mechanical condition (worn timing chain and gears, low compression, etc.). See appropriate article in ENGINES. Restricted exhaust system. See «RESTRICTED EXHAUST»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. Faulty Engine Coolant Temperature (ECT) sensor. See «ENGINE COOLANT TEMPERATURE SENSOR»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l__engine-coolant-temperature-sensor) under SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. Faulty Manifold Absolute Pressure (MAP) sensor. See «MANIFOLD ABSOLUTE PRESSURE SENSOR»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l) under SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. Stuck Throttle Position (TP) sensor. See «DTC P0121: TP SENSOR PERFORMANCE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__dtc-p0121-tp-sensor-performance) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. After completing the actions, go to next step.
  10. Clear the DTCs using a scan tool. Attempt to start the engine. Does the engine start and continue to operate? If yes, go to next step. If no, go to step 2.
  11. Idle the engine. Allow the engine to reach operating temperature. Observe the DTC information using a scan tool. Are any DTCs displayed? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, system is okay at this time.

ENGINE CRANKS BUT DOES NOT RUN (GRAND PRIX & REGAL - VIN K)

Note. For component location and connector terminal identification, see COMPONENT LOCATIONS and CONNECTOR IDENTIFICATION in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. For circuit identification, see WIRING DIAGRAMS .

The Engine Cranks But Does Not Run diagnostic procedure is an organized approach to identifying a condition that causes an engine not to start. The Engine Cranks But Does Not Run diagnostic procedure directs the service technician to the appropriate system diagnosis and assumes that the battery is completely charged, the engine cranking speed is acceptable and there is adequate fuel in the fuel tank.

  1. If diagnostic system check has already been performed, go to next step. If diagnostic system check has not been performed, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  2. Turn ignition switch to RUN position, engine OFF. Observe the DTC information using a scan tool. Is DTC P0101, P0123, P0230, P0336, P0341, P0601, P0602, P1626, P1631 or P2610 set? If yes, diagnose affected DTC(s). See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, go to next step.
  3. Turn ignition switch to RUN position, engine OFF. Probe both sides of the INJ and ELEK fuses using a test light connected to a good ground. Does the test light illuminate on at least one side of each fuse? If yes, go to next step. If no, see «IGNITION RELAY DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__ignition-relay-diagnosis) under IGNITION SYSTEMS.
  4. Observe the engine speed parameter using a scan tool, while the engine is cranking. Does the engine speed parameter display cranking RPM? If yes, go to next step. If no, go to «ELECTRONIC IGNITION SYSTEM DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__electronic-ignition-system-diagnosis) under IGNITION SYSTEMS.
  5. Command the fuel pump relay ON using a scan tool. Does the fuel pump turn ON? If yes, go to next step. If no, go to «FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS (EXCEPT PARK AVENUE)»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__fuel-pump-electrical-circuit-diagnosis-except) under FUEL SYSTEMS.
  6. Turn ignition switch to OFF position. Disconnect a spark plug wire. Install the Spark Tester (J 26792), or equivalent, to the spark plug wire. Attempt to start the engine. Does the spark tester spark? If yes, go to next step. If no, go to «ELECTRONIC IGNITION SYSTEM DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__electronic-ignition-system-diagnosis) under IGNITION SYSTEMS.
  7. Turn ignition switch to OFF position. Disconnect a fuel injector harness connector. Install Fuel Injector Test Light (J 34730-405), or equivalent, to the fuel injector harness connector. Attempt to start the engine. Does the test light blink while the engine is cranking? If yes, go to next step. If no, go to «FUEL INJECTOR CIRCUIT DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__fuel-injector-circuit-diagnosis) under FUEL SYSTEMS.
  8. Turn ignition switch to OFF position. Install Fuel Pressure Gauge (J 34730-1A), or equivalent. (Scheme 407) Turn ignition switch to RUN position, engine OFF. Command the fuel pump relay ON using a scan tool. Is the fuel pressure 53-59 psi (364-405 kPa) while the fuel pump is operating? If yes, go to next step. If no, go to «FUEL SYSTEM DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__fuel-system-diagnosis) under FUEL SYSTEMS.
  9. Check for the following conditions: Collapsed air intake duct. Restricted air filter element. Fouled spark plugs. If the spark plugs are fouled, determine what caused the condition. Repair as necessary. Engine mechanical condition (worn timing chain and gears, low compression, etc.). See appropriate article in ENGINES. Restricted exhaust system. See «RESTRICTED EXHAUST»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. Faulty Engine Coolant Temperature (ECT) sensor. See «ENGINE COOLANT TEMPERATURE SENSOR»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l__engine-coolant-temperature-sensor) under SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. Faulty Manifold Absolute Pressure (MAP) sensor. See «MANIFOLD ABSOLUTE PRESSURE SENSOR»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l) under SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. Stuck Throttle Position (TP) sensor. See «DTC P0121: TP SENSOR PERFORMANCE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__dtc-p0121-tp-sensor-performance) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. After completing the actions, go to next step.
  10. Clear DTCs using a scan tool. Attempt to start the engine. Does the engine start and continue to operate? If yes, go to next step. If no, go to step 2.
  11. Allow engine to idle until normal operating temperature is reached. Observe the DTC Information on scan tool. Are any DTCs displayed? If yes, diagnose affected DTC(s). See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, system is okay at this time.

ENGINE CRANKS BUT DOES NOT RUN (IMPALA & MONTE CARLO - VIN K)

Note. For component location and connector terminal identification, see COMPONENT LOCATIONS and CONNECTOR IDENTIFICATION in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. For circuit identification, see WIRING DIAGRAMS .

The Engine Cranks But Does Not Run diagnostic procedure is an organized approach to identifying a condition that causes an engine not to start. The Engine Cranks But Does Not Run diagnostic procedure directs the service technician to the appropriate system diagnosis. The Engine Cranks But Does Not Run diagnostic procedure assumes the battery is completely charged, the engine cranking speed is acceptable and there is adequate fuel in the fuel tank.

  1. If diagnostic system check has already been performed, go to next step. If diagnostic system check has not been performed, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  2. Turn ignition switch to RUN position, engine OFF. Observe the DTC information using a scan tool. Is DTC P0101, P0123, P0230, P0336, P0341, P0601, P0602, P1626, P1630 or P1631 set? If yes, diagnose affected DTC(s). See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, go to next step.
  3. Turn ignition switch to RUN position, engine OFF. Check both sides of each of the Fuel Injectors and DFI Module fuses using a test light connected to ground. Does the test light illuminate on at least one side of each fuse? If yes, go to next step. If no, see «IGNITION RELAY DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__ignition-relay-diagnosis) under IGNITION SYSTEMS.
  4. Turn ignition switch to RUN position, engine OFF. Observe the MIL. Is the MIL illuminated? If yes, go to next step. If no, go to step 12.
  5. Observe the engine speed parameter using a scan tool. Attempt to start the engine. Does the Engine speed parameter display cranking RPM? If yes, go to next step. If no, go to «ELECTRONIC IGNITION SYSTEM DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__electronic-ignition-system-diagnosis) under IGNITION SYSTEMS.
  6. Command the fuel pump relay ON using a scan tool. Does the fuel pump run? If yes, go to next step. If no, go to «FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS (EXCEPT PARK AVENUE)»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__fuel-pump-electrical-circuit-diagnosis-except) under FUEL SYSTEMS.
  7. Turn ignition switch to OFF position. Disconnect a spark plug wire. Install Spark Tester (J 26792), or equivalent to the spark plug wire. Attempt to start the engine. Does the spark tester spark? If yes, go to next step. If no, go to «ELECTRONIC IGNITION SYSTEM DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__electronic-ignition-system-diagnosis) under IGNITION SYSTEMS.
  8. Turn ignition switch to OFF position. Disconnect a fuel injector connector. Install Fuel Injector Test Light (J 34730-405), or equivalent to the fuel injector harness connector. Attempt to start the engine. Does the test light blink while the engine is cranking? If yes, go to step 10. If no, go to next step.
  9. Remove the Fuel Injector Test Light from the fuel injector harness connector. Turn ignition switch to RUN position, engine OFF. Probe the ignition 1 voltage supply circuit fuel injector using a test light connected to ground. Does the test light illuminate? If yes, go to «DTC P0341: CAMSHAFT POSITION SENSOR PERFORMANCE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__dtc-p0341-camshaft-position-sensor-performance) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  10. Turn ignition switch to OFF position. Install Fuel Pressure Gauge (J 34730-1A), or equivalent. (Scheme 407) Turn ignition switch to RUN position, engine OFF. Command the fuel pump relay ON using a scan tool. Is the fuel pressure 53-59 psi (364-405 kPa) while the fuel pump is operating? If yes, go to next step. If no, go to «FUEL SYSTEM DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__fuel-system-diagnosis) under FUEL SYSTEMS.
  11. Check for the following conditions: A collapsed air intake duct. A restricted air filter element. Fouled spark plugs. If the spark plugs are fouled, determine what caused the condition. Repair as necessary. Engine mechanical condition such as a worn timing chain and gears, low compression, etc. See appropriate article in ENGINES. Restricted exhaust system. See «RESTRICTED EXHAUST»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. Faulty Engine Coolant Temperature (ECT) sensor. See «ENGINE COOLANT TEMPERATURE SENSOR»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l__engine-coolant-temperature-sensor) under SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. Faulty MAP sensor. See «MANIFOLD ABSOLUTE PRESSURE SENSOR»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l) under SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. Stuck Throttle Position (TP) sensor. See «DTC P0121: TP SENSOR PERFORMANCE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__dtc-p0121-tp-sensor-performance) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. Repair as necessary. After repair, go to step 15.
  12. Check the ignition 1 voltage circuit between the ABS/PCM fuse in the junction block-left Instrument Panel (IP) and the Powertrain Control Module (PCM) for an open. Did you find and correct the condition? If yes, go to step 15. If no, go to next step.
  13. Check for an intermittent and for a poor connection at the PCM. Repair as necessary. Did you find and correct the condition? If yes, go to step 15. If no, go to next step.
  14. 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 in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. After repair, go to next step.
  15. Clear DTCs using a scan tool. Attempt to start the engine. Does the engine start and continue to operate? If yes, go to next step. If no, go to step 2.
  16. Allow the engine to idle until normal operating temperature is reached. Observe the DTC Information using a scan tool. Are any DTCs displayed? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, system is okay at this time.

ENGINE CRANKS BUT DOES NOT RUN (PARK AVENUE - VIN 1)

Note. For component location and connector terminal identification, see COMPONENT LOCATIONS and CONNECTOR IDENTIFICATION in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. For circuit identification, see WIRING DIAGRAMS .

The Engine Cranks But Does Not Run diagnostic procedure is an organized approach to identifying a condition that causes an engine not to start. The Engine Cranks But Does Not Run diagnostic procedure directs the service technician to the appropriate system diagnosis and assumes that the battery is completely charged, the engine cranking speed is acceptable and there is adequate fuel in the fuel tank.

  1. If diagnostic system check has already been performed, go to next step. If diagnostic system check has not been performed, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  2. Turn ignition switch to RUN position, engine OFF. Observe the DTC information using a scan tool. Does the scan tool display DTC P0101, P0123, P0230, P0336, P0601, P0602 P1626, P1629, P1631 or P1683? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, go to next step.
  3. Attempt to start the engine. Observe the engine speed parameter while the engine is cranking using a scan tool. Does the engine speed parameter display cranking RPM? If yes, go to next step. If no, go to «ELECTRONIC IGNITION SYSTEM DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__electronic-ignition-system-diagnosis) under IGNITION SYSTEMS.
  4. Command the fuel pump ON, using a scan tool. Does the fuel pump turn ON? If yes, go to next step. If no, go to «FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS (PARK AVENUE)»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__fuel-pump-electrical-circuit-diagnosis-park) under FUEL SYSTEMS.
  5. Turn ignition switch to OFF position. Disconnect a spark plug wire. Install the Spark Tester (J 26792), or equivalent, to the spark plug wire. Attempt to start the engine. Does the spark tester spark? If yes, go to next step. If no, go to «ELECTRONIC IGNITION SYSTEM DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__electronic-ignition-system-diagnosis) under IGNITION SYSTEMS.
  6. Turn ignition switch to OFF position. Disconnect an injector harness connector. Install TBI Harness Test Light (J 34730-2C), or equivalent, to the injector connector. Attempt to start the engine. Does the test light blink while the engine is cranking? If yes, go to next step. If no, go to «FUEL INJECTOR CIRCUIT DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__fuel-injector-circuit-diagnosis) under FUEL SYSTEMS.
  7. Turn ignition switch to OFF position. Connect Fuel Pressure Gauge (J 34730-1A), or equivalent, to the fuel pressure connection, located on the fuel rail. (Scheme 407) Turn ignition switch to RUN position, engine OFF. Command the fuel pump relay ON using a scan tool. Is the fuel pressure 48-54 psi (331-372 kPa) while the fuel pump is operating? If yes, go to next step. If no, go to «FUEL SYSTEM DIAGNOSIS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__fuel-system-diagnosis) under FUEL SYSTEMS.
  8. Check for the following conditions: Collapsed air intake duct. Restricted air filter element. Spark plugs for being gas or coolant fouled. If the spark plugs are fouled, determine what caused the condition. Engine mechanical condition (worn timing chain and gears, low compression, etc.). See appropriate article in ENGINES. Restricted exhaust system. See «RESTRICTED EXHAUST»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. Faulty Engine Coolant Temperature (ECT) sensor. See «ENGINE COOLANT TEMPERATURE SENSOR»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l__engine-coolant-temperature-sensor) under SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. Faulty Manifold Absolute Pressure (MAP) sensor. See «MANIFOLD ABSOLUTE PRESSURE SENSOR»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l) under SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. Stuck Throttle Position (TP) sensor. See «DTC P0121: TP SENSOR PERFORMANCE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__dtc-p0121-tp-sensor-performance) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. After completing the actions, go to next step.
  9. Clear DTCs using a scan tool. Attempt to start the engine. Does the engine start and continue to operate? If yes, go to next step. If no, go to step 2.
  10. Idle the engine. Allow the engine to reach operating temperature. Observe the DTC information using a scan tool. Are any DTCs displayed? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, system is okay at this time.

FUEL SYSTEMS

WARNINGGasoline or gasoline vapors are highly flammable. A fire could occur if an ignition source is present. Never drain or store gasoline or diesel fuel in an open container, due to the possibility of fire or explosion. Have a dry chemical (Class B) fire extinguisher nearby.
WARNINGBefore servicing any electrical component, the ignition key must be in the OFF or LOCK position and all electrical loads must be OFF, unless instructed otherwise in these procedures. If a tool or equipment could easily come in contact with a live exposed electrical terminal, also disconnect the negative battery cable. Failure to follow these precautions may cause personal injury and/or damage to the vehicle or its components.
CAUTIONBegin fuel system trouble shooting and diagnosis with checking fuel injection system pressure. High fuel pressure may be present in fuel lines and component parts. Relieve fuel pressure before disconnecting any fuel system components. See FUEL SYSTEM PRESSURE RELEASE .

Note. For component location and connector terminal identification, see COMPONENT LOCATIONS and CONNECTOR IDENTIFICATION in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. For circuit identification, see WIRING DIAGRAMS .

Pressure Release Procedure

  1. Disconnect the negative battery cable to avoid possible fuel discharge if an accidental attempt is made to start the engine.
  2. Remove the fuel injector sight shield. (Scheme 406) For models not equipped with a supercharger (VIN K), go to next step. For models equipped with a supercharger (VIN 1), go to step 4.
  3. Remove oil filler neck. Lift the front of the fuel injector sight shield up and pull towards the front of the vehicle. (Scheme 406) Remove fuel injector sight shield. Go to step 6.
  4. Clean the area around the tube/oil fill cap before removing the tube/oil fill cap to prevent contaminants from falling into the valve rocker arm cover opening.
  5. Twist counter clockwise to unlock the tube/oil fill cap from the valve rocker arm cover. Remove nut at center of the fuel injector sight shield. Lift the fuel injector sight shield up at the front and slide the tab out of the engine bracket. (Scheme 406) Replace the tube/oil fill cap in the valve rocker arm cover. Go to next step.
  6. Loosen the fuel filler cap to relieve tank vapor pressure.
  7. Connect Fuel Pressure Gauge (J 34730-1A), or equivalent, to the fuel pressure connection, located on the fuel rail. (Scheme 407) Wrap a shop towel around the fuel pressure connection while connecting the fuel pressure gauge to avoid spillage.
  8. Install the bleed hose into an approved container and open the valve to bleed the system pressure. The fuel connections are now safe for servicing.
  9. Drain any fuel remaining in the fuel pressure gauge into an approved container.

Scheme 406

Scheme 406
Scheme 406

Scheme 407

Scheme 407
Scheme 407

FUEL SYSTEM DIAGNOSIS

Note. For component location and connector terminal identification, see COMPONENT LOCATIONS and CONNECTOR IDENTIFICATION in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. For circuit identification, see WIRING DIAGRAMS .

When you turn the ignition switch to RUN position, the Powertrain Control Module (PCM) enables the fuel pump relay which powers the fuel pump ON. The fuel pump remains ON as long as the engine is cranking or running and the PCM receives ignition reference pulses. If there are no ignition reference pulses, the PCM shuts the fuel pump OFF within 2 seconds after the ignition was switched to the RUN position or if the engine stops.

The fuel tank stores the fuel supply. The electric fuel pump supplies fuel through an in-line fuel filter to the fuel injection system. The pump provides fuel at a higher rate of flow than is needed by the fuel injection system. The fuel pressure regulator maintains the correct fuel pressure to the fuel injection system. A separate pipe returns unused fuel to the fuel tank.

Test Description

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

  1. 2 - This step verifies that the fuel pump is operating.
  2. 4 - This step tests for an internal fuel leak. If the fuel pressure decreases during this test, an internal loss of pressure is indicated.
  3. 6 - This step tests the fuel pressure regulator. The fuel pressure regulator is controlled by engine vacuum. With engine vacuum applied, the pressure should decrease by the specified value.
  4. 9 - This step inspects the fuel pressure regulator for a fuel leak from the vacuum port. If fuel leaks from the fuel pressure regulator while the fuel pump is commanded ON, replace the fuel pressure regulator.
  5. 10 - This step tests for a loss of fuel pressure between the shut-off adapter on the fuel feed pipe and the fuel pump.
  6. 11 - This step tests for a leaking fuel injector, or fuel pressure regulator. If the fuel pressure remains constant during this test, the fuel injectors are not leaking fuel.
  7. 14 - This step tests for a restricted fuel return pipe. If the fuel pressure is within the specified values, a restriction in the fuel return pipe is indicated.
  8. 16 - This step determines if the fuel pressure regulator, or the fuel pump, is the cause of the low fuel pressure. If the pressure rises above the specified value, the fuel pump is okay.
  9. 18 - This step verifies that a circuit condition is not the cause of a fuel pressure concern. Check all fuel pump electrical circuits thoroughly.

Note. Verify that adequate fuel is in the fuel tank. Check the fuel system for damage, or external leaks, before proceeding with this diagnostic procedure.

  1. If diagnostic system check has already been performed, go to next step. If diagnostic system check has not been performed, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  2. Turn ignition switch to RUN position, engine OFF. Command the fuel pump ON using a scan tool. Does the fuel pump operate? If yes, go to next step. If no, go to «FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS (EXCEPT PARK AVENUE)»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__fuel-pump-electrical-circuit-diagnosis-except) or «FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS (PARK AVENUE)»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__fuel-pump-electrical-circuit-diagnosis-park).
  3. Turn ignition switch to OFF position. Turn OFF all accessories. Install Fuel Pressure Gauge (J 34730-1A), or equivalent, to the fuel pressure connection, located on the fuel rail. (Scheme 407) Turn ignition switch to RUN position, engine OFF. The fuel pump may need to be commanded ON a few times, to obtain the highest possible fuel pressure. Do NOT start the engine. Command the fuel pump ON using a scan tool. Observe the fuel pressure gauge, with the fuel pump commanded ON. Is the fuel pressure 53-59 psi (364-405 kPa) on models without supercharger (VIN K) or 48-54 psi (334-375 kPa) on models with supercharger (VIN 1)? If yes, go to next step. If no, go to step 12.
  4. Monitor the fuel pressure gauge for one minute. Does the fuel pressure decrease by more than 5 psi (34 kPa)? If yes, go to step 9. If no, go to next step.
  5. Relieve the fuel pressure to 10 psi (69 kPa). Monitor the fuel pressure gauge for 5 minutes. Does the fuel pressure decrease by more than 2 psi (14 kPa)? If yes, go to step 24. If no, go to next step.
  6. Turn ignition switch to OFF position for 15 seconds. Turn ignition switch to RUN position, engine OFF. Monitor the fuel pressure gauge. Start the engine. Does the fuel pressure decrease by 3-10 psi (21-69 kPa) when the engine is started? If yes, go to next step. If no, go to step 8.
  7. Operate the vehicle within the conditions of the customer's concern. Monitor the fuel related parameters using a scan tool. Do any of the scan tool parameters indicate a lean condition? If yes, go to step 17. If no, diagnose by symptom. See «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.
  8. Disconnect the vacuum hose from the fuel pressure regulator. Monitor the fuel pressure gauge. Idle the engine. Apply 12-14 in Hg. (34-47 kPa) of vacuum to the fuel pressure regulator using a hand held vacuum pump. Does the fuel pressure decrease by 3-10 psi (21-69 kPa) when the vacuum is applied? If yes, go to step 21. If no, go to step 23.
  9. Turn ignition switch to OFF position. Remove the vacuum hose from the fuel pressure regulator. Turn ignition switch to RUN position, engine OFF. Command the fuel pump ON using a scan tool. Check for a fuel leak from the fuel pressure regulator vacuum port. Is the fuel pressure regulator leaking fuel? If yes, go to step 23. If no, go to next step.
  10. Turn ignition switch to OFF position. Relieve the fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l). Disconnect the fuel feed hose and the fuel return hose from the fuel rail pipes. Install Fuel Line Shut-off Adapters (J 37287), or equivalent, between the fuel hoses and the fuel rail pipes. Open the valves on the fuel pipe shut-off adapters. Turn ignition switch to RUN position, engine OFF. Command the fuel pump ON using a scan tool. Bleed the air from the fuel pressure gauge. Command the fuel pump ON and then OFF using a scan tool. Close the fuel feed pipe shut-off valve. Monitor the fuel pressure gauge for one minute. Does the fuel pressure remain constant? If yes, go to step 19. If no, go to next step.
  11. Turn ignition switch to OFF position. Open the fuel feed pipe shut-off valve. Turn ignition switch to RUN position, engine OFF. Command the fuel pump ON and then OFF using a scan tool. Close the fuel return pipe shut-off valve. Monitor the fuel pressure gauge for one minute. Does the fuel pressure remain constant? If yes, go to step 23. If no, go to step 20.
  12. Is the fuel pressure more than 59 psi (405 kPa) on models without supercharger (VIN K) or 54 psi (375 kPa) on models with supercharger (VIN 1)? If yes, go to step 14. If no, go to next step.
  13. Is the fuel pressure more than zero psi (zero kPa)? If yes, go to step 16. If no, go to step 17.
  14. Turn ignition switch to OFF position. Relieve the fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l). Disconnect the fuel return hose from the fuel rail pipe. Attach a length of flexible fuel hose to the fuel rail outlet passage. Place the open end of the flexible fuel hose into an approved gasoline container. Turn ignition switch to RUN position, engine OFF. Monitor the fuel pressure gauge while the fuel pump is operating. Is the fuel pressure 53-59 psi (364-405 kPa) on models without supercharger (VIN K) or 48-54 psi (334-375 kPa) on models with supercharger (VIN 1)? If yes, go to step 22. If no, go to next step.
  15. Check the fuel rail return pipe and the fuel rail outlet passage for a restriction. Did you find and correct the condition? If yes, go to step 25. If no, go to step 23.
  16. Turn ignition switch to OFF position. Relieve the fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l). Disconnect the fuel return hose from the fuel rail pipe. Install the Fuel Line Shut-off Adapters between the fuel return pipe and the fuel rail. Open the valve in the fuel pipe shut-off adapter. Turn ignition switch to RUN position, engine OFF. Bleed the air from the fuel system. Monitor the fuel pressure gauge. Do NOT allow the fuel pressure to exceed 75 psi (517 kPa). Excessive pressure may damage the fuel system. Slowly close the valve in the fuel return pipe shut-off adapter. Command the fuel pump ON using a scan tool. Does the fuel pressure increase to more than 59 psi (405 kPa) on models without supercharger (VIN K) or 54 psi (375 kPa) on models with supercharger (VIN 1)? If yes, go to step 23. If no, go to next step.
  17. Check the fuel filter and the fuel feed pipe for a restriction. Did you find and correct the condition? If yes, go to step 25. If no, go to next step.
  18. Check the fuel pump harness connectors and the ground circuits for poor connections. Did you find and correct the condition? If yes, go to step 25. If no, go to next step.
  19. Remove the fuel sender assembly. Check the fuel pump flex hose for damage, the in tank fuel pump harness connectors for poor connections, the fuel strainer for a restriction and for contaminates in the fuel tank. Did you find and correct the condition? If yes, go to step 25. If no, go to step 24.
  20. Turn ignition switch to OFF position. Raise the fuel rail, with the fuel lines connected. Turn ignition switch to RUN position, engine OFF. Command the fuel pump ON using a scan tool. Locate and replace the leaking fuel injector. After repair, go to step 25.
  21. Repair the vacuum source to the fuel pressure regulator. After repair, go to step 25.
  22. Locate and repair the restricted fuel return pipe. After repair, go to step 25.
  23. Check for a missing or damaged fuel pressure regulator "O" ring seal before replacing the fuel pressure regulator. Replace the fuel pressure regulator. After repair, go to step 25.
  24. Replace the fuel pump. After repair, go to next step.
  25. Operate the system to verify the repair. Did you correct the condition? If yes, system is okay at this time. If no, go to step 3.

FUEL INJECTOR CIRCUIT DIAGNOSIS

Note. For component location and connector terminal identification, see COMPONENT LOCATIONS and CONNECTOR IDENTIFICATION in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. For circuit identification, see WIRING DIAGRAMS .

The Powertrain Control Module (PCM) enables the appropriate fuel injector on the intake stroke for each cylinder. An ignition 1 voltage is supplied directly to the fuel injectors. The PCM controls each fuel injector by grounding the control circuit via a solid state device called a driver.

Note. Fuel Injector Circuit Diagnosis testing for Bonneville & LeSabre is not available from manufacturer at this time. See FUEL SYSTEM DIAGNOSIS .

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

Grand Prix

  1. 4 - This step tests for a short to ground on the fuel injector ignition 1 voltage supply circuit, fuse side.
  2. 5 - This step tests for a short to ground on the fuel injector ignition 1 voltage supply circuit.

Impala, Monte Carlo & Park Avenue

  1. 4 - This step tests for a short to ground on the fuel injector ignition 1 voltage supply circuit.
  2. 5 - This step tests for a short to a PCM ground on the fuel injector ignition 1 voltage supply circuit.
  3. 6 - This step tests for an open ignition 1 voltage supply circuit between the fuel injector fuse and the multi-way harness connector.
  4. 7 - This step tests for an open or high resistance between the multi-way harness connector and the fuel injectors.

Regal

  1. 4 - This step tests for a short to ground on the fuel injector ignition 1 voltage supply circuit.
  2. 5 - This step tests for an open ignition 1 voltage supply circuit between the injector fuse and a fuel injector harness connector.

Diagnostic Procedure (Grand Prix)

  1. If diagnostic system check has already been performed, go to next step. If diagnostic system check has not been performed, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  2. Are any fuel injector DTCs set? If yes, go to «DTC P0201-P0206: INJECTOR CONTROL CIRCUIT»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__dtc-p0201-p0206-injector-control-circuit) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, go to next step.
  3. Check the INJ fuse No. 18 (10-amp), located in the underhood junction block. Is the INJ fuse open? If yes, go to next step. If no, go to «DTC P0341: CAMSHAFT POSITION SENSOR PERFORMANCE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__dtc-p0341-camshaft-position-sensor-performance) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  4. Turn ignition switch to OFF position. Disconnect the fuel injector multi-way harness connector. Probe the fuel injector ignition 1 voltage supply circuit, fuse side, using a test light connected to battery voltage. Does the test light illuminate? If yes, go to next step. If no, go to step 6 .
  5. Test the fuel injector ignition 1 voltage supply circuit, between the fuel injector fuse and the fuel injectors for a short to ground. Did you find and correct the condition? If yes, go to step 7 . If no, go to «DIAGNOSTIC AIDS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__diagnostic-aids) .
  6. Inspect for poor connections at the fuel injector harness connectors. Did you find and correct the condition? If yes, go to next step. If no, go to «DIAGNOSTIC AIDS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__diagnostic-aids) .
  7. Operate the system to verify the repair. Did you correct the condition? If yes, system is okay at this time. If no, go to step 3 .

Diagnostic Procedure (Impala & Monte Carlo)

  1. If diagnostic system check has already been performed, go to next step. If diagnostic system check has not been performed, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  2. Are any fuel injector DTCs set? If yes, go to «DTC P0201-P0206: INJECTOR CONTROL CIRCUIT»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__dtc-p0201-p0206-injector-control-circuit) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, go to next step.
  3. Check the fuel injector fuse. Is the fuel injector fuse open? If yes, go to next step. If no, go to step 6 .
  4. Turn ignition switch to OFF position. Disconnect the fuel injector multi-way harness connector. Probe the fuel injector ignition 1 voltage supply circuit, fuse side, using a test light connected to battery voltage. Does the test light illuminate? If yes, go to step 9 . If no, go to next step.
  5. Turn ignition switch to RUN position, engine OFF. Does the test light illuminate? If yes, go to step 13 . If no, go to step 8 .
  6. Turn ignition switch to OFF position. Disconnect the fuel injector multi-way harness connector. Turn ignition switch to RUN position, engine OFF. Probe the fuel injector ignition 1 voltage supply circuit using a test light connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step 10 .
  7. Check for continuity between the ignition 1 voltage supply terminal and a fuel injector terminal, at the multi-way harness connector, fuel injector side. Does the DVOM display infinite? If yes, go to step 11 . If no, go to step 12 .
  8. Check the fuel injector ignition 1 voltage supply circuit, between the multi-way harness connector and the fuel injectors for a short to ground. Did you find and correct the condition? If yes, go to step 14 . If no, go to «INTERMITTENTS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-troubleshooting-no-codes-38l__intermittents) in TROUBLE SHOOTING - NO CODES - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  9. Repair the short to ground in the fuel injector ignition 1 voltage supply circuit. After repair, go to step 14 .
  10. Repair the open in the ignition 1 voltage supply circuit between the Underhood Bussed Electrical Center (UBEC) and splice S109. After repair, go to step 14 .
  11. Repair the fuel injectors ignition 1 voltage supply circuit for an open and/or high resistance, between the multi-way harness connector and splice S109. After repair, go to step 14 .
  12. Repair the poor connections at the multi-way harness connector. After repair, go to step 14 .
  13. Repair the short to a PCM ground in the fuel injector ignition 1 voltage supply circuit. After repair, go to next step.
  14. Operate the system to verify the repair. Did you correct the condition? If yes, system is okay at this time. If no, go to step 3 .

Diagnostic Procedure (Park Avenue)

  1. If diagnostic system check has already been performed, go to next step. If diagnostic system check has not been performed, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  2. Are any fuel injector DTCs set? If yes, go to «DTC P0201-P0206: INJECTOR CONTROL CIRCUIT»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__dtc-p0201-p0206-injector-control-circuit) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, go to next step.
  3. Check the INJR fuse (10-amp), located in left underhood fuse block. Is INJR fuse open? If yes, go to next step. If no, go to «DTC P0341: CAMSHAFT POSITION SENSOR PERFORMANCE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__dtc-p0341-camshaft-position-sensor-performance) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  4. Turn ignition switch to OFF position. Disconnect a fuel injector harness connector. Probe the fuel injector ignition 1 voltage supply circuit using a test light connected to battery voltage. Does test light illuminate? If yes, go to next step. If no, go to step 6 .
  5. Check the fuel injector ignition 1 voltage supply circuit, between the fuel injector fuse and the fuel injectors for a short to ground. Did you find and correct the condition? If yes, go to step 7 . If no, go to «DIAGNOSTIC AIDS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__diagnostic-aids) .
  6. Check for poor connections at the fuel injector harness connectors. Did you find and correct the condition? If yes, go to next step. If no, go to «DIAGNOSTIC AIDS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__diagnostic-aids) .
  7. Operate the system to verify the repair. Did you correct the condition? If yes, system is okay at this time. If no, go to step 3 .

Diagnostic Procedure (Regal)

  1. If diagnostic system check has already been performed, go to next step. If diagnostic system check has not been performed, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  2. Are any fuel injector DTCs set? If yes, go to «DTC P0201-P0206: INJECTOR CONTROL CIRCUIT»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__dtc-p0201-p0206-injector-control-circuit) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, go to next step.
  3. Check the F/INJR fuse No. 28 (15-amp), located in underhood junction block. Is the F/INJR fuse open? If yes, go to next step. If no, go to step 5 .
  4. Turn ignition switch to OFF position. Disconnect a fuel injector harness connector. Turn ignition switch to RUN position, engine OFF. Probe the fuel injector ignition 1 voltage supply circuit using a test light connected to battery voltage. Does the test light illuminate? If yes, go to step 6 . If no, go to «DIAGNOSTIC AIDS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__diagnostic-aids) .
  5. Turn ignition switch to OFF position. Disconnect a fuel injector harness connector. Turn ignition switch to RUN position, engine OFF. Probe the fuel injector ignition 1 voltage supply circuit using a test light connected to a good ground. Does the test light illuminate? If yes, go to «DTC P0341: CAMSHAFT POSITION SENSOR PERFORMANCE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__dtc-p0341-camshaft-position-sensor-performance) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, go to step 7 .
  6. Check each fuel injector ignition 1 voltage supply circuit for a short to ground. Replace the F/INJR fuse. After repair, go to step 8 .
  7. Repair the open or poor connection in the fuel injector ignition 1 voltage supply circuit. After repair, go to next step.
  8. Operate the system to verify the repair. Did you correct the condition? If yes, system is okay at this time. If no, go to step 3 .

Diagnostic Aids

  1. Monitoring the fuel injector circuit status using a scan tool, while moving the fuel injector harness, may help to isolate an intermittent condition.
  2. Performing the Fuel Injector Coil Test may help isolate an intermittent condition. See «FUEL INJECTOR COIL TEST»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing-38l__fuel-injector-coil-test) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  3. For an intermittent condition, go to «INTERMITTENTS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-troubleshooting-no-codes-38l__intermittents) in TROUBLE SHOOTING - NO CODES - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.

FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS (EXCEPT PARK AVENUE)

Note. For component location and connector terminal identification, see COMPONENT LOCATIONS and CONNECTOR IDENTIFICATION in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. For circuit identification, see WIRING DIAGRAMS .

When ignition switch is turned to RUN position, the Powertrain Control Module (PCM) enables the fuel pump relay which powers the fuel pump on. The pump remains ON as long as the engine is cranking or running and the PCM receives ignition reference pulses. If there are no ignition reference pulses, the PCM shuts the fuel pump OFF within 2 seconds after the ignition was switched to the RUN position or if the engine stops.

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

  1. 2 - Command both the ON and OFF states. Repeat the commands as necessary.
  2. 3 - This step determines if the condition is located on the coil side or the switch side of the circuit.
  3. 4 - This step verifies that the PCM is providing voltage to the fuel pump relay.
  4. 5 - This step tests for an open in the ground circuit to the fuel pump relay.
  5. 6 - This step determines if a voltage is constantly being applied to the fuel pump relay.
  6. 12 - To gain access to the fuel pump connector, the fuel tank may need to be removed. This step tests for a grounded fuel pump supply circuit between the fuel pump and the fuel pump fuse.
  7. 13 - This step determines if the condition with the circuit is intermittent. If the fuse does not open, inspect the supply voltage circuit between the fuse and the fuel pump for an intermittent condition.
  8. 15 - Use the same amperage fuse in the jumper as is used to protect the fuel pump circuit.
  9. 16 - To gain access to the fuel pump connector, the fuel tank may need to be removed.
  10. 17 - Check the ground connection for the fuel pump. Ensure all ground connections are clean and tight.
  1. If diagnostic system check has already been performed, go to next step. If diagnostic system check has not been performed, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  2. Turn ignition switch to RUN position, engine OFF. Command the fuel pump relay ON and OFF using a scan tool. Does the fuel pump turn ON and OFF? If yes, go to «INTERMITTENTS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-troubleshooting-no-codes-38l__intermittents) in TROUBLE SHOOTING - NO CODES - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, go to next step.
  3. Command the fuel pump relay ON and OFF using a scan tool. Do you hear a click when you command the fuel pump relay ON and OFF? If yes, go to step 9 . If no, go to next step.
  4. Turn ignition switch to OFF position. Disconnect the fuel pump relay. Turn ignition switch to RUN position, engine OFF. Probe the fuel pump relay control circuit using a test light connected to a good ground. Command the fuel pump relay ON and OFF using a scan tool. Does the test light turn ON and OFF? If yes, go to next step. If no, go to step 6 .
  5. Connect a test light between the fuel pump relay control circuit and the fuel pump relay ground circuit. Command the fuel pump relay ON and OFF using a scan tool. Does the test light turn ON and OFF? If yes, go to step 19 . If no, go to step 22 .
  6. Does the test light remain illuminated with each command? If yes, go to next step. If no, go to step 8 .
  7. Check the fuel pump relay control circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 27 . If no, go to step 26 .
  8. Check the fuel pump relay control circuit for a short to ground or an open. Did you find and correct the condition? If yes, go to step 27 . If no, go to step 20 .
  9. Turn ignition switch to RUN position, engine OFF. Does the fuel pump operate continuously? If yes, go to next step. If no, go to step 11 .
  10. Turn ignition switch to OFF position. Disconnect the fuel pump relay. Turn ignition switch to RUN position, engine OFF. Does the fuel pump operate continuously? If yes, go to step 21 . If no, go to step 25 .
  11. Is the fuel pump fuse open? If yes, go to next step. If no, go to step 14 .
  12. Access fuel sender assembly. Check the fuel pump supply voltage circuit for a grounded circuit between the fuel pump fuse and the fuel pump. Replace the fuel pump fuse if necessary. Did you find and correct the condition? If yes, go to step 27 . If no, go to next step.
  13. Install all disconnected electrical components. Install a NEW fuel pump fuse. Command the fuel pump ON using a scan tool. Is the fuel pump fuse open? If yes, go to step 24 . If no, go to «INTERMITTENTS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-troubleshooting-no-codes-38l__intermittents) in TROUBLE SHOOTING - NO CODES - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  14. Turn ignition switch to OFF position. Disconnect the fuel pump relay. Turn ignition switch to RUN position, engine OFF. Probe the fuel pump relay switch battery voltage circuit using a test light connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step 23 .
  15. Connect a 20-amp fused jumper wire between the fuel pump relay switch battery voltage circuit and the fuel pump supply voltage circuit. Does the fuel pump operate? If yes, go to step 19 . If no, go to next step.
  16. Check the fuel pump supply voltage circuit for an open or high resistance between the fuel pump relay and the fuel pump. Did you find and correct the condition? If yes, go to step 27 . If no, go to next step.
  17. Check the fuel pump ground circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step 27 . If no, go to next step.
  18. Check for poor connections at the fuel pump. Did you find and correct the condition? If yes, go to step 27 . If no, go to step 24 .
  19. Check for poor connections at the fuel pump relay. Did you find and correct the condition? If yes, go to step 27 . If no, go to step 25 .
  20. Check for poor connections at the PCM. Did you find and correct the condition? If yes, go to step 27 . If no, go to step 26 .
  21. Repair the fuel pump supply voltage circuit for a short to voltage. After repair, go to step 27 .
  22. Repair the open in the fuel pump relay ground circuit. After repair, go to step 27 .
  23. Repair the open in the fuel pump relay switch battery voltage circuit. After repair, go to step 27 .
  24. Check for poor connections at the fuel pump, within the fuel tank, before replacing the fuel pump. If connections are okay, replace the fuel pump. After repair, go to step 27 .
  25. Replace the fuel pump relay. After repair, go to step 27 .
  26. 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 in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. After repair, go to next step.
  27. Operate the system to verify the repair. Did you correct the condition? If yes, system is okay at this time. If no, go to step 2 .

The following conditions may have caused the fuel pump fuse to open

  1. The fuse is faulty.
  2. There is an intermittent short in the fuel pump power feed circuit.
  3. The fuel pump has an intermittent internal problem.
  4. For an intermittent condition, go to «INTERMITTENTS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-troubleshooting-no-codes-38l__intermittents) in TROUBLE SHOOTING - NO CODES - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.

FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS (PARK AVENUE)

Note. For component location and connector terminal identification, see COMPONENT LOCATIONS and CONNECTOR IDENTIFICATION in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. For circuit identification, see WIRING DIAGRAMS .

When ignition switch is turned to RUN position, the Powertrain Control Module (PCM) enables the fuel pump relay which powers the fuel pump on. The pump remains ON as long as the engine is cranking or running and the PCM receives ignition reference pulses. If there are no ignition reference pulses, the PCM shuts the fuel pump OFF within 2 seconds after the ignition was switched to the RUN position or if the engine stops.

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

  1. 2 - Command both the ON and OFF states. Repeat the commands as necessary.
  2. 3 - This step determines if the condition is located on the coil side or the switch side of the circuit.
  3. 4 - This step verifies that the PCM is providing voltage to the fuel pump relay.
  4. 5 - This step tests for an open in the ground circuit to the fuel pump relay.
  5. 6 - This step determines if a voltage is constantly being applied to the fuel pump relay.
  6. 12 - This step tests for a grounded fuel pump supply circuit between the fuel pump and the fuel pump fuse.
  7. 13 - This step determines if the condition with the circuit is intermittent. If the fuse does not open, inspect the supply voltage circuit between the fuse and the fuel pump for an intermittent condition.
  8. 15 - Use the same amperage fuse in the jumper as is used to protect the fuel pump circuit.
  9. 16 - This step tests the fuel pump supply circuit between the fuel pump and the fuel pump relay for an open or high resistance.
  10. 17 - This step tests the fuel pump ground circuit for an open or high resistance.
  1. If diagnostic system check has already been performed, go to next step. If diagnostic system check has not been performed, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  2. Turn ignition switch to RUN position, engine OFF. Command the fuel pump relay ON and OFF using a scan tool. Does the fuel pump turn ON and OFF? If yes, go to «INTERMITTENTS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-troubleshooting-no-codes-38l__intermittents) in TROUBLE SHOOTING - NO CODES - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, go to next step.
  3. Command the fuel pump relay ON and OFF using a scan tool. Do you hear a click when you command the fuel pump relay ON and OFF? If yes, go to step 9 . If no, go to next step.
  4. Turn ignition switch to OFF position. Disconnect the fuel pump relay. Turn ignition switch to RUN position, engine OFF. Probe the fuel pump relay control circuit using a test light connected to a good ground. Command the fuel pump relay ON and OFF using a scan tool. Does the test light turn ON and OFF? If yes, go to next step. If no, go to step 6 .
  5. Connect a test light between the fuel pump relay control circuit and the fuel pump relay ground circuit. Command the fuel pump relay ON and OFF using a scan tool. Does the test light turn ON and OFF? If yes, go to step 19 . If no, go to step 22 .
  6. Does the test light remain illuminated with each command? If yes, go to next step. If no, go to step 8 .
  7. Disconnect the Powertrain Control Module (PCM) harness connectors. Check the fuel pump relay control circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 27 . If no, go to step 26 .
  8. Disconnect the Powertrain Control Module (PCM) harness connectors. Check the fuel pump relay control circuit for a short to ground or an open. Did you find and correct the condition? If yes, go to step 27 . If no, go to step 20 .
  9. Turn ignition switch to RUN position, engine OFF. Does the fuel pump operate continuously? If yes, go to next step. If no, go to step 11 .
  10. Turn ignition switch to OFF position. Disconnect the fuel pump relay. Turn ignition switch to RUN position, engine OFF. Does the fuel pump operate continuously? If yes, go to step 21 . If no, go to step 25 .
  11. Is the F/PMP fuse (20-amp) open? F/PMP fuse is located in the left underhood junction block. If yes, go to next step. If no, go to step 14 .
  12. Remove the fuel sender access panel, located under the rear compartment floor trim. Check the fuel pump supply voltage circuit for a grounded circuit between the fuel pump fuse and the fuel pump. Replace the fuel pump fuse if necessary. Did you find and correct the condition? If yes, go to step 27 . If no, go to next step.
  13. Install all disconnected electrical components. Install a new F/PMP fuse. Command the fuel pump ON using a scan tool. Is the F/PMP fuse open? If yes, go to step 24 . If no, go to «INTERMITTENTS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-troubleshooting-no-codes-38l__intermittents) in TROUBLE SHOOTING - NO CODES - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  14. Turn ignition switch to OFF position. Disconnect the fuel pump relay. Turn ignition switch to RUN position, engine OFF. Probe the fuel pump relay switch battery voltage circuit using a test light connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step 23 .
  15. Connect a 20-amp fused jumper wire between the fuel pump relay switch battery voltage circuit and the fuel pump supply voltage circuit. Does the fuel pump operate? If yes, go to step 19 . If no, go to next step.
  16. Remove the fuel sender access panel. Check the fuel pump supply voltage circuit for an open or high resistance between the fuel pump relay and the fuel pump. Did you find and correct the condition? If yes, go to step 27 . If no, go to next step.
  17. Check the fuel pump ground circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step 27 . If no, go to next step.
  18. Check for poor connections at the fuel pump. Did you find and correct the condition? If yes, go to step 27 . If no, go to step 24 .
  19. Check for poor connections at the fuel pump relay. Did you find and correct the condition? If yes, go to step 27 . If no, go to step 25 .
  20. Check for poor connections at the PCM harness connectors. Did you find and correct the condition? If yes, go to step 27 . If no, go to step 26 .
  21. Repair the fuel pump supply voltage circuit for a short to voltage. After repair, go to step 27 .
  22. Repair the open in the fuel pump relay ground circuit. After repair, go to step 27 .
  23. Repair the open in the fuel pump relay switch battery voltage circuit. After repair, go to step 27 .
  24. Check for poor connections at the fuel pump, within the fuel tank, before replacing the fuel pump. If connections are okay, replace the fuel pump. After repair, go to step 27 .
  25. Replace the fuel pump relay. After repair, go to step 27 .
  26. 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 in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. After repair, go to next step.
  27. Operate the system to verify the repair. Did you correct the condition? If yes, system is okay at this time. If no, go to step 2 .

For an intermittent condition, go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.

IGNITION SYSTEMS

Note. For circuit identification, see WIRING DIAGRAMS .

ELECTRONIC IGNITION SYSTEM DIAGNOSIS

Note. For component location and connector terminal identification, see COMPONENT LOCATIONS and CONNECTOR IDENTIFICATION in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. For circuit identification, see WIRING DIAGRAMS .

This ignition system uses one coil for each pair of cylinders, mounted to the Ignition Control Module (ICM). Companion cylinders are a pair of cylinders that are at Top Dead Center (TDC) at the same time. The cylinder that is at TDC of the compression stroke is called the event cylinder. The cylinder that is at TDC of the exhaust stroke is called the waste cylinder. When the coil is triggered both companion cylinder spark plugs fire at the same time, completing a series circuit.

The ICM has independent power and ground circuits. The circuits between the ICM and the Powertrain Control Module (PCM) consists of the following circuits

  1. The Ignition Control (IC) timing signal.
  2. The IC timing control.
  3. The low resolution engine speed signal.
  4. The medium resolution engine signal.
  5. The camshaft position signal.
  6. The low reference.

The ICM sends 3X signals to the PCM, and controls the timing advance during engine cranking. The timing advance changes to PCM control after the following actions occur

  1. The PCM receives the second 3X signal.
  2. The PCM applies 5 volts to the Ignition Control (IC) timing signal circuit.

The ICM monitors the CKP sync signal when the engine is cranking. The CKP sync signal is passed from the CKP sensor to the ICM on the CKP sensor 2 signal circuit. The CKP sync signal is used to determine the correct cylinder pair and initiate the ignition coil firing sequence. The 18X reference pulses are passed from the CKP sensor to the ICM on the CKP sensor 1 circuit. The 18X reference pulses are used for fuel injection and ignition control. After the ICM receives both signals, the ICM passes the 18X and 3X reference signals to the PCM. The CMP and the CKP sensors share a 12 volt reference and low reference circuit. The CKP sensor consists of the following circuits

  1. A 12 volt reference.
  2. A low reference.
  3. A CKP sensor 1 signal.
  4. A CKP sensor 2 signal.

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

  1. 3 - Determines if the Ignition Control (IC) module is receiving the CKP sensor 1 signal. If the CKP sensor 1 signal to the ICM is not present, there will be no RPM, spark, or fuel injector pulses.
  2. 4 - Ensures that the IC module has the proper voltage supply and ground.
  3. 6 - Verifies that the IC module is supplying the 12-volt reference to the sensor.
  1. If diagnostic system check has already been performed, go to next step. If diagnostic system check has not been performed, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  2. Check the fuses which supply ignition 1 voltage to the Ignition Control Module (ICM) and the Powertrain Control Module (PCM). Are either of the fuses open? If yes, go to step 27 . If no, go to next step.
  3. Turn ignition switch to RUN position, engine OFF. Crank the engine. Observe the engine RPM parameter using a scan tool. Does the scan tool display engine RPM? If yes, go to step 13 . If no, go to next step.
  4. Turn ignition switch to OFF position. Disconnect the ICM. Turn ignition switch to RUN position, engine OFF. Connect a test light between the ICM ignition 1 voltage circuit and the ICM ground circuit. Does the test light illuminate? If yes, go to step 6 . If no, go to next step.
  5. Leave the ICM disconnected. Connect the test light between the ICM ignition 1 voltage and a good ground. Does the test light illuminate? If yes, go to step 28 . If no, go to step 29 .
  6. Turn ignition switch to OFF position. Reconnect the ICM. Disconnect the Crankshaft Position (CKP) sensor harness connector. Turn ignition switch to RUN position, engine OFF. Connect a DVOM between the CKP sensor 12-volt reference circuit and the CKP sensor ground circuit. Is the difference between the measured voltage and the system voltage more than 0.5 volt? If yes, go to step 8 . If no, go to next step.
  7. Connect the DVOM between the CKP sensor 1 signal circuit and the CKP sensor ground circuit. Is the voltage 6-8 volts? If yes, go to step 16 . If no, go to step 11 .
  8. Connect the DVOM between the CKP sensor 12-volt reference circuit and a good ground. Is the difference between the measured voltage and the system voltage more than 0.5 volt? If yes, go to next step. If no, go to step 10 .
  9. Turn ignition switch to OFF position. Leave the CKP sensor disconnected. Disconnect the ICM harness connector. Check the CKP sensor ground circuit for an open. Did you find and correct the condition? If yes, go to step 33 . If no, go to step 27 .
  10. Turn ignition switch to OFF position. Leave the CKP sensor disconnected. Disconnect the ICM harness connector. Check the CKP 12-volt reference circuit for an open and for a short to ground. Did you find and correct the condition? If yes, go to step 35 . If no, go to step 26 .
  11. Leave the DVOM connected. Turn ignition switch to OFF position. Disconnect the ICM harness connector. Turn ignition switch to RUN position, engine OFF. Is the difference between the measured voltage and the system voltage more than 0.5 volt? If yes, go to step 30 . If no, go to next step.
  12. Check the CKP sensor 1 signal circuit for an open or a short to ground. Did you find and correct the condition? If yes, go to step 35 . If no, go to step 26 .
  13. Turn ignition switch to OFF position. Disconnect a spark plug wire from a spark plug. Install Spark Tester (J 26792), or equivalent, in the end of the spark plug wire. Jump the companion cylinder's ignition wire to a good ground. The companion cylinder is the cylinder that shares the same ignition coil. Crank the engine while observing the spark. Repeat the above test for each ignition wire, noting any cylinders that do not have spark. Do all of the cylinders have spark? If yes, go to step 23 . If no, go to next step.
  14. Do any of the cylinders have spark? If yes, go to step 19 . If no, go to next step.
  15. Turn ignition switch to OFF position. Disconnect the CKP sensor harness connector. Turn ignition switch to RUN position, engine OFF. Connect the DVOM between the CKP sensor 2 signal circuit and a good ground. Is the measured voltage 6-8 volts? If yes, go to next step. If no, go to step 17 .
  16. Check for intermittent and for a poor connection at the CKP sensor. Did you find and correct the condition? If yes, go to step 35 . If no, go to step 32 .
  17. Turn ignition switch to OFF position. Disconnect the ICM harness connector. Turn ignition switch to RUN position, engine OFF. Check the CKP sensor 2 signal circuit for a short to voltage or a short to the sensor 12-volt reference circuit. Did you find and correct the condition? If yes, go to step 35 . If no, go to next step.
  18. Check the CKP sensor 2 signal for a short to ground or an open. Did you find and correct the condition? If yes, go to step 35 . If no, go to step 26 .
  19. Check the ignition coils and the ignition wires associated with the cylinders that did not have spark. Verify that the ignition components are free of cracks and carbon tracking. Replace any damaged ignition components. Did you find and correct the condition? If yes go to step 35 . If no, go to next step.
  20. Measure the ignition coils secondary resistance. Is the resistance 5-8 k/ohms? If yes, go to next step. If no, go to step 34 .
  21. Measure the resistance of the ignition wires associated with the cylinders that did not have spark. Is the resistance more than 3 k/ohms per foot? If yes, go to step 31 . If no, go to next step.
  22. Remove the coils associated with the cylinder that did not have spark. Connect a test light across the ignition module primary circuit, between the ICM terminals, for the coils. Observe the test light while cranking the engine. Does the test light flash continuously while the engine is being cranked? If yes, go to step 34 . If no, go to step 33 .
  23. Remove the spark plugs from all of the cylinders. Check the spark plug electrodes. Are any of the spark plugs fouled? If yes, check engine compression. See «CYLINDER COMPRESSION PRESSURE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__cylinder-compression-pressure) under MECHANICAL INSPECTION.
  24. Check for a short between the ICM CKP sensor 1 and CKP sensor 2 circuits. Did you find and correct the condition? If yes, go to step 35 . If no, go to next step.
  25. Check for a short between the medium resolution and low resolution speed signal circuits to the PCM. Did you find and correct the condition? If yes, go to step 35 . If no, check engine compression. See «CYLINDER COMPRESSION PRESSURE»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-controls-basic-diagnostic-procedures-38l__cylinder-compression-pressure) under MECHANICAL INSPECTION.
  26. Check for an intermittent and for a poor connection at the ICM. Did you find and correct the condition? If yes, go to step 35 . If no, go to step 33 .
  27. Repair the short to ground in the affected circuit. After repair, go to step 35 .
  28. Repair the open in the ICM ground circuit. After repair, go to step 35 .
  29. Repair the open in the ignition 1 voltage circuit. After repair, go to step 35 .
  30. Repair the short to voltage in the CKP sensor 1 signal circuit. After repair, go to step 35 .
  31. Replace the spark plug wires. After repair, go to step 35 .
  32. Replace the CKP sensor. After repair, go to step 35 .
  33. Replace the ICM. After repair, go to step 35 .
  34. Replace the ignition coils associated with the cylinders that did not have spark. After repair, go to next step.
  35. Attempt to start the engine. Does the engine start and continue to run? If yes, go to next step. If no, go to step 2 .
  36. Clear the DTCs using a scan tool. Turn ignition switch to OFF position for 30 seconds. Start the engine. Let the engine reach operating temperature. Are there any DTCs that have not been diagnosed? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/park-avenue/ii-2002-2005/remont/testing-diagnostics/#engine-control-system-self-diagnostics-38l__diagnostic-trouble-code-definitions) in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, system is okay at this time.

IGNITION RELAY DIAGNOSIS

Note. Manufacturer does not provide testing procedures for many individual systems and components. For ignition relay diagnosis for LeSabre and Park Avenue, see ELECTRONIC IGNITION SYSTEM DIAGNOSIS .

For diagnosis, see IGNITION RELAY (BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO & PARK AVENUE) or IGNITION RELAY (REGAL) under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.

IDLE SPEED & IGNITION TIMING

Ensure idle speed and ignition timing are set to specification. For specifications and adjustments, see appropriate SERVICE & ADJUSTMENT SPECIFICATIONS and ON-VEHICLE ADJUSTMENTS articles.

BONNEVILLE

See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

GRAND PRIX

See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

IMPALA

See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

LESABRE

See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

MONTE CARLO

See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

PARK AVENUE

See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

REGAL

See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

See also:
• DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS
• COMPUTER RELEARN PROCEDURES - GENERAL MOTORS
• DIAGNOSTIC TROUBLE CODE DEFINITIONS
• RESTRICTED EXHAUST
• ENGINE COOLANT TEMPERATURE SENSOR
• DTC P0121: TP SENSOR PERFORMANCE
• DTC P0341: CAMSHAFT POSITION SENSOR PERFORMANCE
• SYMPTOMS
• DTC P0201-P0206: INJECTOR CONTROL CIRCUIT
• INTERMITTENTS
• FUEL INJECTOR COIL TEST
• IGNITION RELAY (BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO & PARK AVENUE)
• IGNITION RELAY (REGAL)
• VISUAL INSPECTION
• PCM/ICM FUSE LOCATION
• ELECTRONIC IGNITION SYSTEM DIAGNOSIS
• FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS (EXCEPT PARK AVENUE)
• FUEL SYSTEM DIAGNOSIS
• FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS (PARK AVENUE)
• FUEL INJECTOR CIRCUIT DIAGNOSIS
• IGNITION RELAY DIAGNOSIS
• DIAGNOSTIC AIDS
• CYLINDER COMPRESSION PRESSURE

More articles — Engine Performance