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Engine Controls - Trouble Shooting - No Codes: Other Pontiac Aztek I

Testing & Diagnostics ~5936 words

Possible Causes & Corrections

Check the following items

  1. Fuel system circuits for proper operation. Refer to FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS in «FUEL SYSTEMS»(ref-152619-S32565021802003021700000) in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
  2. Low fuel pressure. Refer to «FUEL SYSTEMS»(ref-152619-S32565021802003021700000) in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
  3. Faulty fuel injectors. Refer to «FUEL SYSTEMS»(ref-153136-S29653111982003031900000) in SYSTEM & COMPONENT TESTING - 3.4L AZTEK & RENDEZVOUS article.
  4. Fuel contamination.
  5. Inspect any items which may cause an engine to run rich. Using scan tool, long term fuel trim is significantly in the negative range.
  6. Inspect any items which may cause an engine to run lean. Using scan tool, long term fuel trim is significantly in the positive range.
  7. Inspect spark plugs for proper heat range and reach.
  8. Inspect for proper ignition voltage output using Spark Tester (J-26792).
  9. If spark is not present at the coils, inspect ignition coil for cracks, carbon tracking/arcing, coil resistance value out of range (5000-8000 ohms). Check spark plug wires for signs of arcing, crossfiring, cracks, carbon tracking, plug boot damage, pinched, improper routing, or a resistance value out of range (3000 ohms per foot). Check for defective ignition module, ignition system wiring, loose ignition module feed or ground connection, or damaged system wiring.
  10. Remove spark plugs and inspect for fouled plugs, cracks, wear improper gap burned or damaged electrodes improper heat range or reach.
  11. If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.
  12. Low engine coolant.
  13. Restricted air flow to radiator or restricted water flow through the radiator.
  14. Inoperative electric cooling fan circuits.
  15. Correct coolant solution should be a 50/50 mix.
  16. Excessive oil in combustion chamber or leaking valve seals.
  17. Low cylinder compression. Refer to «MECHANICAL INSPECTION»(ref-152619-S15977923652003021700000) under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
  18. Incorrect basic engine parts. Inspect cylinder heads, camshaft, valve train components, pistons, etc.
  19. Test the CKP sensor "B" for an internal short. Refer to Electronic Ignition System in «IGNITION SYSTEMS»(ref-152619-S40142985842003021700000) in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
  20. Test for proper EGR system operation. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.
  21. Inspect the Transaxle Range Switch input with the vehicle in Drive and gear selector in Drive or Overdrive. See appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.
  22. Test the Torque Converter Clutch (TCC) operation. TCC applying too soon can cause engine to spark knock.
  23. If scan tool readings are normal and there are no engine mechanical faults, fill the fuel tank with a known-good quality gasoline that has a minimum octane rating of 87 and re-evaluate vehicle performance.

Check the following items

  1. Search for bulletins.
  2. Monitor the 24X crank sensor and CMP sensor signal present parameters on scan tool. If both are not responding, test the sensor feed circuit. Both sensors use a separate feed circuit but are internally connected to power. Test all CKP sensor "A" and CMP sensor circuits for intermittents. Monitor the 3X parameter on scan tool. If 3X is not responding, inspect CKP sensor "B" and circuits for intermittents. Inspect the Ignition Control (IC) circuit, IC timing control circuit, low resolution engine speed signal circuit and the low reference circuit for intermittents. If these circuits become open or shorted, they may not set a DTC immediately, but are capable of causing driveability complaints. Test the CKP sensor "B" for an internal short. Refer to Electronic Ignition System Diagnosis in «IGNITION SYSTEMS»(ref-152619-S40142985842003021700000) in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
  3. Inspect Mass Airflow (MAF) sensor conditions. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article. Ensure that MAF sensor honeycomb is not damaged.
  4. Test for low fuel pressure. Refer to Fuel System Diagnosis in «FUEL SYSTEMS»(ref-152619-S32565021802003021700000) in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
  5. Test for contaminated fuel.
  6. Ensure each injector harness is connected to the correct injector/cylinder.
  7. Inspect for proper ignition voltage output.
  8. If spark is not present at the coils, inspect for coil for cracks, carbon tracking/arcing, or a resistance value outside the specified range (5000-8000 ohms). Check spark plug wires for signs of arcing, crossfiring, cracks, carbon tracking, plug boot damage, pinched, improper routing, or a resistance value outside the specified range (3000 ohms per foot). Spraying secondary ignition wires with a light mist of water may help locate an intermittent problem. Ignition voltage will arc to ground when a secondary component is faulty. Check for defective ignition module, ignition system wiring, loose ignition module feed or ground connection or damaged system wiring.
  9. Remove spark plugs and inspect for fouled plugs cracks wear improper gap, burned or damaged electrodes, improper heat range or reach. If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.
  10. Test compression. Refer to «MECHANICAL INSPECTION»(ref-152619-S15977923652003021700000) under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article. Low compression can be caused by sticking or leaking valves, worn camshaft lobes, valve timing, bent push rods, worn rocker arms, or broken valve springs. Check for excessive oil in combustion chamber, caused by leaking valve seals. Check for incorrect basic engine parts, such as camshaft, cylinder heads, pistons, etc.
  11. Inspect intake and exhaust manifolds for casting flash.
  12. Test Torque Converter Clutch (TCC) operation. Refer to appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.
  13. Inspect exhaust system for possible restriction. Inspect exhaust system for damaged or collapsed pipes. Inspect mufflers for heat distress or possible internal failure. Inspect for possible plugged catalytic converter.

Check the following items

  1. Search for bulletins.
  2. Test fuel system circuits for proper operation. Refer to Fuel Pump Electrical Circuit Diagnosis in «FUEL SYSTEMS»(ref-152619-S32565021802003021700000) in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
  3. Test for low fuel pressure. Refer to «FUEL SYSTEMS»(ref-152619-S32565021802003021700000) in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
  4. Test for faulty fuel injectors. Refer to «FUEL SYSTEMS»(ref-153136-S29653111982003031900000) in SYSTEM & COMPONENT TESTING - 3.4L AZTEK & RENDEZVOUS article.
  5. Inspect for fuel contamination.
  6. Inspect any items which may cause an engine to run rich. Using scan tool, long term fuel trim is significantly in the negative range.
  7. Inspect any items which may cause an engine to run lean. Using scan tool, long term fuel trim is significantly in the positive range.
  8. Inspect for conditions which may cause an incorrect idle speed: Throttle body tampering, excessive deposits or damage. Check for restricted air intake system or large vacuum leak. Check for collapsed air intake ducts. Check for improper installation or leaks especially between the MAF sensor and throttle body.
  9. Inspect Throttle Position (TP) sensor and related circuit wiring. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.
  10. Monitor the 24X crank sensor and CMP sensor signal parameters on scan tool. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article. If both are not responding, test the sensor feed circuit. Both sensors use a separate feed circuit but are internally connected to power. Test all CKP sensor "A" and CMP sensor circuits for intermittents.
  11. Monitor the 3X crank sensor parameter on the scan tool. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article. If 3X crank sensor parameter is not responding, inspect the CKP sensor "B" and circuits for intermittents. Inspect the Ignition Control (IC) circuit, IC timing control circuit, low resolution engine speed signal circuit and the low reference circuit for intermittents. If these circuits become open, or shorted, they may not set a DTC immediately, but are capable of causing driveability complaints.
  12. Test CKP sensor "B" for an internal short. Refer to Electronic Ignition System diagnosis under «IGNITION SYSTEMS»(ref-152619-S40142985842003021700000) in SYSTEM & COMPONENT TESTING - 3.4L AZTEK & RENDEZVOUS article.
  13. Test EGR system for proper operation. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.
  14. Test PCV valve for proper operation. See «EMISSION SYSTEMS & SUB-SYSTEMS»(ref-153136-S32939651532003031900000) in SYSTEM & COMPONENT TESTING - 3.4L AZTEK & RENDEZVOUS article.
  15. Inspect the transaxle range switch input with vehicle in Drive and the gear selector in Drive or Overdrive.
  16. Inspect for bent balancer interrupter rings or damaged crankshaft position sensor.
  17. Inspect for proper ignition voltage output using Spark Tester (J-26792).
  18. If spark is not present at the coils, inspect for coils for cracks, carbon tracking/arcing, or a resistance value that is out of range (5000-800 ohms). Check spark plug wires for signs of arcing, crossfiring, cracks, carbon tracking, plug boot damage, pinched, or improper routing. Check spark plug wire resistance (3000 ohms per foot). Check for defective ignition module, ignition system wiring, loose ignition module feed or ground connection, or damaged system wiring.
  19. Remove spark plugs and inspect for fouled plugs, cracks, wear, improper gap, burned or damaged electrodes, improper heat range or reach. Check if spark plugs are gas or oil fouled. Cause of fouling must be determined before replacing the spark plugs. Check compression. Refer to «MECHANICAL INSPECTION»(ref-152619-S15977923652003021700000) under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article. Low compression can be caused by sticking or leaking valves, worn camshaft lobes, valve timing, bent push rods, worn rocker arms or broken valve springs. Check for excessive oil in combustion chamber. Check for incorrect basic engine parts, such as camshaft, cylinder heads, pistons, etc.
  20. Inspect exhaust system for possible restrictions. Inspect exhaust system for damaged or collapsed pipes. Inspect mufflers for heat distress or possible internal failure. Check for possible plugged catalytic converter.
  21. An engine miss condition can be caused by Electromagnetic Interference (EMI) on the reference circuit. EMI can usually be detected by monitoring engine RPM with a scan tool. A sudden increase in RPM with little change in actual engine RPM change, indicates EMI is present. If a problem exists, inspect routing of secondary ignition wires or high voltage components near ignition control circuits.

Check for the following

  1. Search for bulletins.
  2. Test fuel system circuits for proper operation. Refer to Fuel Pump Electrical Circuit Diagnosis in «FUEL SYSTEMS»(ref-153136-S29653111982003031900000) in SYSTEM & COMPONENT TESTING - 3.4L AZTEK & RENDEZVOUS article.
  3. Test for low fuel pressure. Refer to «FUEL SYSTEMS»(ref-152619-S32565021802003021700000) in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
  4. Test for faulty fuel injectors. Refer to «FUEL SYSTEMS»(ref-153136-S29653111982003031900000) in SYSTEM & COMPONENT TESTING - 3.4L AZTEK & RENDEZVOUS article.
  5. Inspect for fuel contamination.
  6. Inspect for fuel in the pressure regulator vacuum hose.
  7. Ensure each injector harness is connected to the correct injector/cylinder.
  8. Test for short between battery positive voltage and any of the ignition feed circuits.

Check the following items

  1. Search for bulletins.
  2. Test Engine Coolant Temperature (ECT) sensor for being shifted in value. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article or connect a scan tool and compare engine coolant temperature with Intake Air Temperature (IAT) on a cold engine. The ECT and IAT should be within 5°F (3°C) of each other. Test resistance of ECT sensor if temperature is out of range with IAT sensor.
  3. Monitor the 24X crank sensor and CMP sensor signal present parameters on a scan tool. If both are not responding, test the sensor feed circuit. Both sensors use a separate feed circuit but are internally connected to power. Test all CKP sensor "A" and CMP sensor circuits for intermittents. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.
  4. Monitor the 3X crank sensor parameter on the scan tool. If the 3X crank sensor parameter is not responding, inspect the CKP sensor "B" and circuits for intermittents. Inspect the Ignition Control (IC) circuit, IC timing control circuit, low resolution engine speed signal circuit and the low reference circuit for intermittents. If these circuits become open or shorted, they may not set a DTC immediately, but are capable of causing driveability complaints. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.
  5. Inspect Mass Airflow (MAF) sensor for proper installation and conditions. A MAF sensor with a damaged honeycomb may cause a hard start.
  6. Inspect the air intake ducts for being collapsed, damaged areas, looseness, improper installation, or leaking, especially between the MAF sensor and the throttle body.
  7. Using a scan tool, test Idle Air Control (IAC) operation. Command engine speed to 1500 RPM and back to the starting RPM. If engine RPM does not change when commanded, diagnose IAC circuit.
  8. Inspect EGR system for proper sealing/connections and operation. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.
  9. Test fuel system circuits for proper operation. Refer to Fuel Pump Electrical Circuit Diagnosis in «FUEL SYSTEMS»(ref-153136-S29653111982003031900000) in SYSTEM & COMPONENT TESTING - 3.4L AZTEK & RENDEZVOUS article.
  10. Test for low fuel pressure. Refer to «FUEL SYSTEMS»(ref-152619-S32565021802003021700000) in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
  11. Test for faulty fuel injectors. Refer to «SYSTEM & COMPONENT TESTING - 3.4L AZTEK & RENDEZVOUS»(ref-153136) article.
  12. Inspect for fuel contamination.
  13. Inspect for proper ignition voltage output using Spark Tester (J-26792).
  14. If spark is not present at the coils, inspect for coils for cracks, carbon tracking/arcing, or a resistance value outside the specified range (5000-8000 ohms). Check spark plug wires for signs of arcing, crossfiring, cracks, carbon tracking, plug boot damage, pinched, improper routing, or a resistance value outside the specified range (3000 ohms per foot). Check for defective ignition module, ignition system wiring, loose ignition module feed or ground connection, or damaged system wiring.
  15. Remove spark plugs and inspect for fouled plugs, cracks, wear, improper gap, burned or damaged electrodes, improper heat range or reach.
  16. If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.
  17. Excessive oil in combustion chamber.
  18. Low cylinder compression. Refer to «MECHANICAL INSPECTION»(ref-152619-S15977923652003021700000) under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
  19. For incorrect basic engine parts, such as cylinder heads, camshaft, valve train components, pistons, etc.

Check for the following items

  1. Search for bulletins.
  2. Monitor the Heated Oxygen Sensors (HO2S). See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article. The HO2S should respond quickly to different throttle positions. If not, inspect the HO2S for Silicone or other contaminants from fuel or use of improper RTV sealant. The sensors may have a White powdery coating. Silicone contamination causes a high but false HO2S signal voltage, rich exhaust indication. The PCM will reduce the amount of fuel delivered to the engine, causing a severe driveability problem.
  3. Monitor the 24X crank sensor and CMP sensor signal present parameters on scan tool. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article. If both are not responding, test the sensor feed circuit. Both sensors use a separate feed circuit but are internally connected to power. Test all CKP "A" and CMP sensor circuits for intermittents.
  4. Monitor the 3X crank sensor parameter on scan tool. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article. If the 3X crank sensor parameter is not responding, inspect the CKP sensor "B" and circuits for intermittents. Inspect the Ignition Control (IC) circuit, IC timing control circuit, low resolution engine speed signal circuit and the 3X low reference circuit for intermittents. If these circuits become open or shorted they may not set a DTC immediately, but are capable of causing driveability complaints.
  5. Test the CKP sensor "B" for an internal short. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.
  6. Inspect Throttle Position (TP) sensor and related wiring. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.
  7. Inspect Mass Airflow (MAF) sensor and related wiring. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article. Inspect the air intake ducts for being collapsed, damaged areas, looseness, improper installation, or leaking especially between the MAF sensor and the throttle body.
  8. Test the EGR system for proper operation.
  9. Test the fuel system circuits for proper operation. Refer to Fuel Pump Electrical Circuit Diagnosis in «FUEL SYSTEMS»(ref-153136-S29653111982003031900000) in SYSTEM & COMPONENT TESTING - 3.4L AZTEK & RENDEZVOUS article.
  10. Test for low fuel pressure. Refer to «FUEL SYSTEMS»(ref-152619-S32565021802003021700000) in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
  11. Test for faulty fuel injectors. Refer to «FUEL SYSTEMS»(ref-153136-S29653111982003031900000) in SYSTEM & COMPONENT TESTING - 3.4L AZTEK & RENDEZVOUS article.
  12. Inspect for fuel contamination.
  13. Inspect any items which may cause an engine to run rich. Using scan tool, a long term fuel trim is significantly in the negative range.
  14. Inspect any items which may cause an engine to run lean. Using scan tool, a long term fuel trim is significantly in the positive range.
  15. Inspect for proper ignition voltage output using Spark Tester (J-26792).
  16. If spark is not present at the coils, inspect for coils for cracks, carbon tracking/arcing, or a resistance value outside the specified range (5000-8000 ohms). Check spark plug wires for signs of arcing, crossfiring, cracks, carbon tracking, plug boot damage, pinched, improper routing, or a resistance value outside the specified range (3000 ohms per foot). Check for defective ignition module, ignition system wiring, loose ignition module feed or ground connection, or damaged system wiring.
  17. Remove spark plugs and inspect for fouled plugs, cracks, wear, improper gap, burned or damaged electrodes, improper heat range or reach.
  18. If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs

Check the following items

  1. Search for bulletins.
  2. Test the fuel system circuits for proper operation. Refer to Fuel Pump Electrical Circuit Diagnosis in «FUEL SYSTEMS»(ref-153136-S29653111982003031900000) in SYSTEM & COMPONENT TESTING - 3.4L AZTEK & RENDEZVOUS article.
  3. Test for low fuel pressure. Refer to «FUEL SYSTEMS»(ref-152619-S32565021802003021700000) in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
  4. Test for faulty fuel injectors. Refer to «FUEL SYSTEMS»(ref-153136-S29653111982003031900000) in SYSTEM & COMPONENT TESTING - 3.4L AZTEK & RENDEZVOUS article.
  5. Inspect for fuel contamination.
  6. Inspect any items which may cause an engine to run rich. Using scan tool, long term fuel trim is significantly in the negative range.
  7. Inspect any items which may cause an engine to run lean. Using scan tool, long term fuel trim is significantly in the positive range.
  8. Test the CKP sensor "B" for an internal short. Refer to Electronic Ignition System in «IGNITION SYSTEMS»(ref-152619-S40142985842003021700000) in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
  9. Using a scan tool, monitor Knock Sensor (KS) system for excessive spark retard activity. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.
  10. If knock retard is greater than 10-12 degrees, disconnect KS, and ground the sensor harness connector. Monitor knock retard on scan tool. There should be no knock retard present. If knock retard is still present, replace PCM.
  11. Inspect EGR system for proper operation. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.
  12. Inspect the air intake ducts for being collapsed, damaged areas, looseness, improper installation, or leaking especially between the Mass Airflow (MAF) sensor and throttle body.
  13. Inspect for proper ignition voltage output using Spark Tester (J-26792).
  14. If spark is not present at the coils, inspect coils for cracks, carbon tracking/arcing, or a resistance value outside the specified range (5000-8000 ohms). Check spark plug wires for signs of arcing, crossfiring, cracks, carbon tracking, plug boot damage, pinched, improper routing, or a resistance value outside the specified range (3000 ohms per foot). Check for defective ignition module, ignition system wiring, loose ignition module feed or ground connection, or damaged system wiring.
  15. Remove spark plugs and inspect for fouled plugs, cracks, wear, improper gap, burned or damaged electrodes, improper heat range or reach.
  16. If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.
  17. Excessive oil in combustion chamber, caused by leaking valve seals.
  18. Low cylinder compression. Refer to «MECHANICAL INSPECTION»(ref-152619-S15977923652003021700000) under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
  19. For incorrect basic engine parts such as cylinder heads, camshaft, valve train components, pistons, etc.
  20. Inspect the exhaust system for any possible restrictions. Inspect exhaust system for damaged or collapsed pipes. Inspect mufflers for heat distress or possible internal failure. Inspect for possible plugged catalytic converter. Test for proper Torque Converter Clutch (TCC) operation. See appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.

Check the following items

  1. Search for bulletins.
  2. Observe the owner's driving habits. Is the A/C on full time and defroster mode on? Are the tires at the correct pressure? Are excessively heavy loads being carried? Is acceleration too much, too often?
  3. Test the fuel system circuits for proper operation. Refer to Fuel Pump Electrical Circuit Diagnosis under «FUEL SYSTEMS»(ref-153136-S29653111982003031900000) in SYSTEM & COMPONENT TESTING - 3.4L AZTEK & RENDEZVOUS article.
  4. Test for low fuel pressure. Refer to «FUEL SYSTEMS»(ref-152619-S32565021802003021700000) in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
  5. Test for faulty fuel injectors. Refer to «FUEL SYSTEMS»(ref-153136-S29653111982003031900000) in SYSTEM & COMPONENT TESTING - 3.4L AZTEK & RENDEZVOUS article.
  6. Inspect for fuel contamination.
  7. Ensure each injector harness is connected to the correct injector/cylinder.
  8. Inspect for fuel in the pressure regulator vacuum hose.
  9. Observe the 24X crank sensor and CMP sensor signal parameters on scan tool. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article. If both are not responding, check the sensor feed circuit. Both sensors use a common feed circuit.
  10. Inspect air intake system and crankcase for air leaks.
  11. Inspect air intake ducts for being collapsed, damaged areas, looseness, improper installation, or leaking, especially between the MAF sensor and throttle body.
  12. Inspect for proper operation of the speedometer.
  13. Inspect for proper ignition voltage output using Spark Tester (J-26792).
  14. If spark is not present at the coils, inspect coils for cracks, carbon tracking/arcing, or a resistance value outside the specified range (5000-8000 ohms). Check spark plug wires for signs of arcing, crossfiring, cracks, carbon tracking, plug boot damage, pinched, improper routing, or a resistance value outside the specified range (3000 ohms per foot). Check for defective ignition module, ignition system wiring, loose ignition module feed or ground connection, or damaged system wiring.
  15. Remove spark plugs and inspect for fouled plugs, cracks, wear, improper gap, burned or damaged electrodes, improper heat range or reach.
  16. If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.
  17. Inspect engine coolant for correct level.
  18. Inspect for incorrect or faulty engine thermostat.
  19. Check engine compression. Refer to «MECHANICAL INSPECTION»(ref-152619-S15977923652003021700000) under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article. Low compression can be caused by sticking or leaking valves, worn camshaft lobes, valve timing, bent push rods, worn rocker arms or broken valve springs. Check for excessive oil in combustion chamber, which can be caused by leaking valve seals.
  20. For incorrect basic engine parts such as camshaft, cylinder heads, pistons, etc.
  21. Test the Torque Converter Clutch (TCC) operation. See appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.
  22. Inspect exhaust system for possible restriction. Inspect exhaust system for damaged or collapsed pipes. Inspect mufflers for heat distress or possible internal failure. Inspect for possible plugged catalytic converter.

Possible Cause & Correction

Check the following items

  1. Fill limiter vent valve stuck closed.
  2. Fill limiter vent valve stuck closed.
  3. Restricted Evaporative Emission (EVAP) canister.
  4. EVAP vent valve stuck closed.
  5. High Reid Vapor Pressure (RVP) or high fuel temperature.
  6. Fuel filler hose is pinched or kinked.
  7. Fill limiter vent valve stuck closed.
  8. EVAP canister blocked.
  9. EVAP vent valve stuck closed.
  10. Restricted or pinched EVAP vapor lines.
  11. Blocked fuel filler hose/pipe or fuel fill check valve.
  12. Pressure relief valve is stuck open or leaking.
  13. Fill limiter vent valve is stuck open or leaking.

Check the following items

  1. Search for bulletins
  2. Test the fuel system circuits for proper operation. Refer to Fuel Pump Electrical Circuit Diagnosis in «FUEL SYSTEMS»(ref-153136-S29653111982003031900000) in SYSTEM & COMPONENT TESTING - 3.4L AZTEK & RENDEZVOUS article.
  3. Test for low fuel pressure. Refer to «FUEL SYSTEMS»(ref-152619-S32565021802003021700000) in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
  4. Test for faulty fuel injectors. Refer to «FUEL SYSTEMS»(ref-153136-S29653111982003031900000) in SYSTEM & COMPONENT TESTING - 3.4L AZTEK & RENDEZVOUS article.
  5. Inspect for fuel contamination.
  6. Inspect for fuel in the pressure regulator vacuum hose.
  7. Ensure each injector harness is connected to the correct injector/cylinder.
  8. Inspect for any items which may cause an engine to run rich. Using scan tool, long term fuel trim is significantly in the negative range.
  9. Inspect for any items which may cause an engine to run lean. Using scan tool, long term fuel trim is significantly in the positive range.
  10. Test for conditions which cause an incorrect idle speed. Check for throttle body tampering, excessive deposits or damage. Check for restricted air intake system or large vacuum leak.
  11. Inspect the air intake ducts for being collapsed, damaged areas, looseness, improper installation, or leaking especially between the MAF sensor and the throttle body.
  12. Inspect crankcase ventilation valve for proper operation. See «EMISSION SYSTEMS & SUB-SYSTEMS»(ref-153136-S32939651532003031900000) in SYSTEM & COMPONENT TESTING - 3.4L AZTEK & RENDEZVOUS article.
  13. Inspect the Throttle Position (TP) sensor and related wiring. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.
  14. Monitor the 24X crank sensor and CMP sensor signal present parameters on scan tool. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article. If both are not responding, test the sensor feed circuit. Both sensors use a separate feed circuit but are internally connected to power. Test all CKP sensor "A" and CMP sensor circuits for intermittents.
  15. Monitor the 3X parameter on the scan tool. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article. If the 3X is not responding, inspect the CKP sensor "B" and circuits for intermittents. Inspect the Ignition Control (IC) circuit, IC timing control circuit, low resolution engine speed signal circuit and the low reference circuit for intermittents. If these circuits become open or shorted, they may not set a DTC immediately, but are capable of causing driveability complaints.
  16. Test EGR system for proper operation. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.
  17. Inspect the Transaxle Range Switch input with the vehicle in Drive and the gear selector in Drive or Overdrive.
  18. Inspect for proper ignition voltage output using Spark Tester (J-26792).
  19. If spark is not present at the coils, inspect coils for cracks, carbon tracking/arcing, or a resistance value outside the specified range (5000-8000 ohms). Check spark plug wires for signs of arcing, crossfiring, cracks, carbon tracking, plug boot damage, pinched, improper routing, or a resistance value outside the specified range (3000 ohms per foot). Check for defective ignition module, ignition system wiring, loose ignition module feed or ground connection, or damaged system wiring.
  20. Remove spark plugs and inspect for fouled plugs, cracks, wear, improper gap, burned or damaged electrodes, improper heat range or reach.
  21. If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.
  22. Inspect engine mechanical for low compression. Refer to «MECHANICAL INSPECTION»(ref-152619-S15977923652003021700000) under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article. Low compression can be caused by sticking or leaking valves, worn camshaft lobes, valve timing, bent push rods, worn rocker arms, or broken valve springs. Check for excessive oil in combustion chamber, which can be caused by leaking valve seals.
  23. Inspect for incorrect basic engine parts, such as camshaft, cylinder heads, pistons, etc.
  24. Inspect exhaust system for damaged or collapsed pipes.
  25. Inspect mufflers for heat distress or possible internal failure.
  26. Inspect for possible plugged three-way catalytic converter. See «MECHANICAL INSPECTION»(ref-152619-S15977923652003021700000) under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
  27. An engine miss condition can be caused by Electromagnetic Interference (EMI) on the reference circuit. EMI can usually be detected by monitoring engine RPM with a scan tool. A sudden increase in RPM with little change in actual engine RPM change, indicates EMI is present. If a problem exists, inspect the routing of secondary ignition wires, high voltage components, e.g. near ignition control circuits.
  28. Inspect for intake and exhaust manifold passages for casting flash.

Check for the following items

  1. Search for bulletins.
  2. Be sure driver understands transmission Torque Converter Clutch (TCC) and A/C compressor operation, as explained in the owner's manual. Inform customer how TCC and A/C clutch operates.
  3. Monitor the Heated Oxygen Sensors (HO2S). See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article. The HO2S should respond quickly to different throttle positions. If not, inspect the HO2S for Silicone or other contaminants from fuel or use of improper RTV sealant. The sensors may have a White powdery coating. Silicone contamination causes a high but false HO2S signal voltage which is a rich exhaust indication. The PCM will reduce the amount of fuel delivered to the engine, causing a severe driveability problem.
  4. Inspect the Mass Airflow (MAF) sensor and related wiring. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.
  5. Inspect the air intake ducts for being collapsed, damaged areas, looseness, improper installation, or leaking especially between the MAF sensor and throttle body.
  6. Monitor the 24X crank sensor and the CMP sensor signal present parameters on the scan tool. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article. If both sensors are not responding, test each sensor feed circuit. Each sensor uses a separate supply circuit but are internally connected to power. Test all CKP sensor "A" and CMP sensor circuits for intermittents.
  7. Monitor the 3X crank sensor parameter on the scan tool. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article. If the 3X crank sensor parameter is not responding, inspect the CKP sensor "B" and related circuits for intermittents. Inspect the Ignition Control (IC) circuit, IC timing control circuit, low resolution engine speed signal circuit and the low reference circuit for intermittents. If these circuits become open or shorted may not set a DTC immediately, but are capable of causing driveability complaints.
  8. Test the CKP sensor "B" for an internal short. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.
  9. Test the EGR system for proper operation. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-155075-S27919636112003060600000) in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.
  10. Test the fuel pressure. Refer to «FUEL SYSTEMS»(ref-152619-S32565021802003021700000) in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
  11. Inspect for contaminated fuel.
  12. Ensure each fuel injector harness is connected to the correct fuel injector/cylinder.
  13. Inspect any items which may cause an engine to run rich. Using scan tool, long term fuel trim is significantly in the negative range.
  14. Inspect any items that may cause an engine to run lean. Using scan tool, long term fuel trim is significantly in the positive range.
  15. Inspect for proper ignition voltage output using Spark Tester (J-26792).
  16. Test the TCC operation.
  17. Inspect the exhaust system for possible restriction. Inspect exhaust system for damaged or collapsed pipes. Inspect muffler for heat distress or possible internal failure. Test for possible plugged catalytic converter by testing the exhaust system backpressure.

RESTRICTED EXHAUST

For dual exhaust systems a quick check of exhaust flow will help determine which side of the exhaust system is restricted. The side that has less exhaust flow is the side that will be suspect, and diagnosis should begin there. To diagnose exhaust system, refer to EXHAUST SYSTEM BACKPRESSURE under MECHANICAL INSPECTION under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.

INTERMITTENTS

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

PRELIMINARY

Perform the Diagnostic System Check-Engine Controls before starting. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.

CONTROL MODULE POWER & GROUNDS, & COMPONENT POWER & GROUNDS

Poor power or ground connections can cause widely varying symptoms.

  1. Test all control module power circuits. Many vehicles have multiple circuits supplying power to the control module. Other components in the system may have separate power circuits that may also need to be tested. Inspect connections at the module or component connectors, fuses, and any intermediate connections between the power source and the module or component. A test light or a Digital Volt-Ohmmeter (DVOM) may indicate that voltage is present, but neither tests the ability of a circuit to carry sufficient current. Ensure that the circuit can carry the current necessary to operate the component. See POWER DISTRIBUTION in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
  2. Test all control module ground and system ground circuits. The control module may have multiple ground circuits. Other components in the system may have separate grounds that may also need to be tested. Inspect grounds for clean and tight connections at the grounding point. Inspect the connections at the component and in splice packs, where applicable. Ensure that the circuit can carry the current necessary to operate the component. See GROUND DISTRIBUTION in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

TEMPERATURE SENSITIVITY

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

INCORRECT PCM PROGRAMMING

  1. There are only a few situations when reprogramming a PCM is appropriate, such as the following: A new service PCM is installed. A PCM from another vehicle is installed. Revised software or calibration files have been released for this vehicle.
  2. Verify that the PCM contains the correct software or calibration. If incorrect programming is found, reprogram the PCM with the most current software or calibration. See «POWERTRAIN CONTROL MODULE»(ref-155075-S39693243352003060600000) under PROGRAMMING in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.

DUPLICATING FAILURE CONDITIONS

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

VEHICLE DATA RECORDER

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

More articles — Engine Controls - Trouble Shooting - No Codes