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Engine Controls - 3.9L - Troubleshooting & Diagnosis: Diagnosis Chevrolet Uplander I

Testing & Diagnostics ~3438 words

Important Preliminary Inspections Before Starting

Before using the Symptom tables, perform the following

  1. Perform «Diagnostic System Check - Vehicle»(ref-241670-S16610990062006081100000) and verify all of the following items: Ensure that the engine control module (ECM) and malfunction indicator lamp (MIL) are operating correctly. Ensure that there are no diagnostic trouble codes (DTCs) that are stored. Scan tool data is within a normal operating range. Refer to «Scan Tool Data List»(ref-241748-S22574443422006081100000) .
  2. Verify the customer concern.
  3. Perform the Visual/Physical Inspection in this article The visual/physical inspection is extremely important and can lead to correcting a condition without additional testing. It may also help reveal the cause of an intermittent condition.
  4. Locate the correct symptom. Perform the tests and inspections associated with the symptom.

Symptoms

Use the following symptoms in order to isolate possible systems that are associated with the condition

SymptomsAction/System
Find the symptom in the left column and perform the test/inspection procedure in the right column
Hard Start BackfireTip: A vehicle with a camshaft actuator stuck in an un-parked position may experience a hard start. Start and run the engine until fully warm. Observe the camshaft position (CMP) variation parameter while accelerating up to 1,500 RPM and back to idle several times. The CMP variation should indicate a value for 1-2 seconds and then return to 0 degree. If the camshaft actuator does not respond, refer to Camshaft Position Actuator Cleaning and Inspection and Camshaft Position Actuator Magnet Cleaning and Inspection . Symptoms - Fuel System Symptoms - Ignition System Symptoms - Sensors/Systems Engine exhaust-Refer to Symptoms - Engine Exhaust . Inspect the engine mechanical for oil consumption, correct engine compression and correct base engine timing-Refer to Symptoms - Engine Mechanical . Backfire-Inspect the intake and exhaust system and associated passages for casting flash. Inspect the engine cooling system for correct level and operation-Refer to Symptoms - Engine Cooling . Inspect the engine electrical system for correct operation-Refer to Charging System Test .
Surges/ChugglesTip: A vehicle with a camshaft actuator uncontrolled and wandering may experience an engine surge. Start and run the engine until fully warm. Observe the CMP variation parameter while accelerating up to 1,500 RPM and back to idle several times. The CMP variation should indicate a value for 1-2 seconds and then return to 0 degree. If the camshaft actuator does not respond, refer to Camshaft Position Actuator Cleaning and Inspection and Camshaft Position Actuator Magnet Cleaning and Inspection . Symptoms - Fuel System Symptoms - Ignition System Symptoms - Sensors/Systems Inspect the engine mechanical for oil consumption, correct engine compression and correct base engine timing-Refer to Symptoms - Engine Mechanical . Inspect the engine mechanical for correct engine oil pressure. Incorrect oil pressure may cause the camshaft actuator to vary beyond the device control when operated. Refer to Oil Pressure Diagnosis and Testing . Inspect the engine electrical system for correct operation-Refer to Charging System Test . Engine exhaust-Refer to Restricted Exhaust . Ensure the customer understands the operation of the Automatic Transmission including the Tap shift option if applicable. Inspect the automatic transmission for proper shifting and torque converter clutch (TCC) engagement-Refer to Symptoms - Automatic Transmission . HVAC System operation- Ensure the customer understands the operation of the HVAC system. Refer to the following: Air Conditioning (A/C) System Performance Test Symptoms - HVAC Systems - Manual Symptoms - HVAC Systems - Automatic
Lack of Power, Sluggishness or SponginessTip: A vehicle with a camshaft actuator stuck in the park position may experience a lack of power during take off. Start and run the engine until fully warm. Observe the CMP variation parameter while accelerating up to 1,500 RPM and back to idle several times. The CMP variation should indicate a value for 1-2 seconds and then return to 0 degree. If the camshaft actuator does not respond, refer to Camshaft Position Actuator Cleaning and Inspection and Camshaft Position Actuator Magnet Cleaning and Inspection . Symptoms - Fuel System Symptoms - Ignition System Symptoms - Sensors/Systems Inspect for a restricted air intake system. Inspect for a dirty or restricted air filter. Inspect the engine mechanical for oil consumption, correct engine compression and correct base engine timing-Refer to Symptoms - Engine Mechanical . Inspect the engine mechanical for correct engine oil pressure. Incorrect oil pressure may cause the camshaft actuator to vary beyond the device control when operated. Refer to Oil Pressure Diagnosis and Testing . Inspect the engine electrical system for correct operation-Refer to Charging System Test . Engine Exhaust-Refer to Restricted Exhaust . Ensure the customer understands the operation of the Automatic Transmission including the Tap shift option if applicable. Inspect the automatic transmission for proper shifting and TCC engagement-Refer to Symptoms - Automatic Transmission . Torque Management System, if applicable-Refer to CELL LINK ABS Description and Operation and Symptoms - Antilock Brake System . HVAC System operation-Refer to the following: Air Conditioning (A/C) System Performance Test Symptoms - HVAC Systems - Manual Symptoms - HVAC Systems - Automatic .
Hesitation, Sag, Stumble Cuts Out, Misses Rough, Unstable or Incorrect Idle and StallingIMPORTANT: A rough idle may be considered a normal condition at start-up if the engine oil temperature is below -7°C (+19.4°F). This condition may last up to 200 seconds until the oil temperature warms enough to allow stable operation of the camshaft actuator. Tip: A vehicle with a camshaft actuator stuck at full camshaft retard may experience a rough idle.Start and run the engine until fully warm. Observe the CMP variation parameter while accelerating up to 1,500 RPM and back to idle several times. The CMP variation should indicate a value for 1-2 seconds and then return to 0 degree. If the camshaft actuator does not respond, refer to Camshaft Position Actuator Cleaning and Inspection and Camshaft Position Actuator Magnet Cleaning and Inspection . Symptoms - Fuel System Symptoms - Ignition System Symptoms - Sensors/Systems Inspect for a restricted air intake system. Inspect for a dirty or restricted air filter. Ensure correct engine oil is used. Incorrect oil for the temperature may cause variations with camshaft actuator operation. Inspect the intake manifold tuning valve for leaks at the seal and for proper operation. An uncontrolled tuning valve may cause isolations in the air flow-refer to intake manifold tuning valve inspection in the Intake Manifold Replacement - Upper . Inspect the engine mechanical for oil consumption, correct engine compression and correct base engine timing-Refer to Symptoms - Engine Mechanical . Inspect the engine mechanical for correct engine oil pressure. Incorrect oil pressure may cause the camshaft actuator to vary beyond the device control when operated. Refer to Oil Pressure Diagnosis and Testing . Inspect the engine electrical system for correct operation-Refer to Charging System Test . Engine Cooling System-Refer to Symptoms - Engine Cooling . Engine Exhaust-Refer to Restricted Exhaust . Inspect the engine mounts. Refer to Engine Mount Inspection . Inspect the crankcase ventilation system-Refer to Positive Crankcase Ventilation (PCV) Valve Cleaning and Inspection . Inspect the air intake system for leaks and unmetered air HVAC System operation-Refer to the following: Air Conditioning (A/C) System Performance Test Symptoms - HVAC Systems - Manual Symptoms - HVAC Systems - Automatic Inspect the automatic transmission for proper shifting and TCC engagement-Refer to Symptoms - Automatic Transmission . Inspect the transmission range switch for proper operation. Refer to Range Selector Displays Incorrect Range (3.5L) or Range Selector Displays Incorrect Range (3.9L) . Inspect the transmission mounts. Refer to CELL LINK 142106 for the F40 transmission or Transmission Mount Inspection for the 4T65E transmission.
Detonation/Spark KnockExcessive heavy loads or review owner's driving habits-Consult the Vehicle Owner's Manual. Ensure quality fuel is used-Consult the Vehicle Owner's Manual Symptoms - Fuel System Symptoms - Ignition System Inspect the engine mechanical for the following: Oil consumption Carbon build up or other hot point within the combustion chamber Correct engine compression Correct base engine timing Refer to Symptoms - Engine Mechanical . Engine Cooling System-Refer to Engine Overheating . Inspect the automatic transmission for proper shifting and TCC engagement-Refer to Symptoms - Automatic Transmission .
Poor Fuel EconomyProper tire inflation-Refer to Tires in Service and Appearance Care in the vehicle Owner's Manual. Inspect for a dirty or restricted air filter. Fuel Quality-Refer to the following: Alcohol/Contaminants-in-Fuel Diagnosis Fuel Service and Appearance Care in the vehicle Owner's Manual Symptoms - Fuel System Symptoms - Ignition System Symptoms - Sensors/Systems Inspect the engine mechanical for oil consumption, correct engine compression and correct base engine timing-Refer to Symptoms - Engine Mechanical . Inspect the crankcase ventilation system-Refer to Positive Crankcase Ventilation (PCV) Valve Cleaning and Inspection . Tip: A vehicle with a camshaft actuator either stuck at full camshaft retard, in the park position or uncontrolled and wandering may experience poor fuel economy. Start and run the engine until fully warm. Observe the CMP variation parameter while accelerating up to 1,500 RPM and back to idle several times. The CMP variation should indicate a value for 1-2 seconds and then return to 0 degree. If the camshaft actuator responds erratic or inconsistent or not at all, refer to Camshaft Position Actuator Cleaning and Inspection and Camshaft Position Actuator Magnet Cleaning and Inspection . Inspect the engine cooling system for correct level and operation-Refer to Symptoms - Engine Cooling . Engine Electrical System operation-Refer to Charging System Test . Engine Exhaust-Refer to Symptoms - Engine Exhaust . HVAC System operation. Ensure the customer understands the operation of the HVAC system-Refer to the following: Air Conditioning (A/C) System Performance Test Symptoms - HVAC Systems - Manual Symptoms - HVAC Systems - Automatic . Ensure the customer understands the operation of the Automatic Transmission including the Tap shift option if applicable. Inspect the automatic transmission for proper shifting and TCC engagement-Refer to Symptoms - Automatic Transmission . Inspect the Braking System-Refer to BRAKES DRAG .
Dieseling/Run-OnSymptoms - Fuel System Symptoms - Ignition System Inspect the engine mechanical for the following: Carbon build up or other hot point within the combustion chamber Correct engine compression Correct base engine timing Refer to Symptoms - Engine Mechanical . Inspect the intake and exhaust system and associated passages for casting flash.
IMPORTANT
A rough idle may be considered a normal condition at start-up if the engine oil temperature is below -7°C (+19.4°F). This condition may last up to 200 seconds until the oil temperature warms enough to allow stable operation of the camshaft actuator.

Symptoms

Symptoms - Fuel System

SymptomsFuel System
Find the symptom in the left column and perform the test/inspection procedure in the right column, be sure to review each cell of the table to identify all tests for a symptom.
Hard Start Surges/Chuggles Lack of Power, Sluggishness or Sponginess Detonation/Spark Knock Hesitation, Sag, Stumble Cuts Out, Misses Poor Fuel Economy Rough, Unstable or Incorrect Idle and Stalling BackfireTest the fuel system for correct operation, restriction, volume and pressure. Refer to Fuel System Diagnosis and Fuel Pump Electrical Circuit Diagnosis . Inspect for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis . Inspect the throttle body for coking. Refer to THROTTLE BODY INSPECTION AND CLEANING . Inspect for lean or rich conditions. Refer to P0171, P0172, P0173 or P0174 conditions for running the DTC.
Dieseling/Run OnTest the fuel system for excessive fuel pressure. Refer to Fuel System Diagnosis .
Hard Start Surges/Chuggles Lack of Power, Sluggishness or Sponginess Detonation/Spark Knock Hesitation, Sag, Stumble Cuts Out, Misses Poor Fuel Economy Rough, Unstable or Incorrect Idle and Stalling Dieseling, Run-OnTest for proper operation of the fuel injectors. Refer to Fuel Injector Diagnosis .
Surges/Chuggles Lack of Power, Sluggishness or Sponginess Hesitation, Sag, Stumble Cuts Out, Misses Rough, Unstable or Incorrect Idle and StallingInspect the evaporative emission (EVAP) system for the following: Excess fuel in the EVAP lines and/or in the EVAP canister. Refer to Evaporative Emissions (EVAP) Hose Routing Diagram . Integrity-Refer to System Testing in DTC P0442 .

Fuel System

Symptoms - Ignition System

SymptomsIgnition System
Find the symptom in the left column and perform the test/inspection procedure in the right column, be sure to review each cell of the table to identify all tests for a symptom.
Hard Start Surges/Chuggles Lack of Power, Sluggishness or Sponginess Detonation/Spark Knock Hesitation, Sag, Stumble Cuts Out, Misses Poor Fuel Economy Rough, Unstable or Incorrect Idle and Stalling Dieseling, Run-On BackfireInspect for proper Ignition System operation. Refer to Electronic Ignition (EI) System Diagnosis . Inspect spark plugs and spark plug wires. Refer to SPARK PLUG INSPECTION and SPARK PLUG WIRE INSPECTION . Inspect the spark plugs for correct application. Refer to Ignition System Specifications .
Hard Start Surges/Chuggles Lack of Power, Sluggishness or Sponginess Hesitation, Sag, Stumble Cuts Out, Misses Poor Fuel Economy Rough, Unstable or Incorrect Idle and Stalling BackfireInspect the crankshaft position (CKP) sensor for the following: CKP sensor for damage and proper installation-Refer to CRANKSHAFT POSITION SENSOR REPLACEMENT and CKP SYSTEM VARIATION LEARN PROCEDURE . Inspect the CKP Sensor and corresponding harness for electro-magnetic interference (EMI).

Ignition System

Symptoms - Sensors/Systems

SymptomsSensor/System
Find the symptom in the left column and perform the test/inspection procedure in the right column, be sure to review each cell of the table to identify all tests for a symptom.
Hard Start Surges/Chuggles Hesitation, Sag, Stumble Cuts Out, Misses Poor Fuel Economy Rough, Unstable or Incorrect Idle and Stalling BackfireInspect the mass air flow (MAF) sensor for proper installation, obstruction, contamination and damage. Refer to MASS AIRFLOW SENSOR/INTAKE AIR TEMPERATURE SENSOR REPLACEMENT . Inspect the MAF sensor for proper seating of the connector and terminals. Inspect the manifold absolute pressure (MAP) sensor for proper installation, obstruction and damage. Refer to MANIFOLD ABSOLUTE PRESSURE SENSOR REPLACEMENT . Ensure the quality of the MAP sensor vacuum source.
Hard Start Detonation/Spark Knock Hesitation, Sag, Stumble Poor Fuel Economy Rough, Unstable or Incorrect Idle and StallingInspect for vacuum leaks and other unmetered air. Test the engine coolant temperature (ECT) sensor for being shifted in value. Refer to the Temperature vs Resistance - Engine Coolant Temperature (ECT) Sensor .
Surges/Chuggles Lack of Power, Sluggishness or Sponginess Detonation/Spark Knock Poor Fuel Economy BackfireMonitor the Knock Sensor (KS) System for excessive spark retard activity. Refer to the Knock Sensor description within in the Electronic Ignition (EI) System Description .
Hesitation, Sag, StumbleInspect the accelerator pedal position (APP) sensor and the related wiring. Inspect the Throttle Actuator Control (TAC) System for proper operation.
Surges/Chuggles Lack of Power, Sluggishness or Sponginess Hesitation, Sag, Stumble Cuts Out, Misses Poor Fuel Economy Rough, Unstable or Incorrect Idle and Stalling BackfireInspect for contaminated oxygen sensor (O2S).
Poor Fuel EconomyInspect for proper operation of the speedometer. Refer to Speedometer and/or Odometer Inaccurate or Inoperative .
Hard Start Surges/Chuggles Poor Fuel Economy Rough, Unstable or Incorrect Idle and Stalling BackfireInspect the camshaft actuator for correct operation. Refer to Camshaft Actuator System Description . Inspect the intake manifold tuning valve for correct operation. Refer to Intake Manifold Tuning Valve System Description

Sensor/System

Diagnostic Fault Information

IMPORTANTAlways perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Scan Tool Reference

Scan Tool Data List

Circuit/System Testing

  1. Turn OFF the ignition.
  2. Disconnect the ECM.
  3. Turn ON the ignition with the engine OFF. If the MIL is still ON, test the MIL control circuit for a short to ground. If the MIL control circuit tested OK and the MIL stayed ON, replace the instrument panel cluster (IPC). If the MIL control circuit tested OK and the MIL went out when the ECM was disconnected, replace the ECM.
  4. Measure for 12 volts from the MIL ignition voltage circuit in the ECM harness connector to a ground. If there is less than 12 volts, test the MIL ignition voltage circuit for an open or a short to ground and an open fuse.
  5. Remove the fuse that supplies voltage to the MIL.
  6. Measure for less than 1 volt from the MIL control circuit in the ECM harness connector to a good ground. If there is more than 1 volt, test the MIL control circuit for a short to voltage.
  7. Install the fuse that supplies voltage to the MIL.
  8. The MIL should illuminate with a 3-amp fused jumper wire connected between the MIL control circuit in the ECM harness connector and a good ground. If the MIL does not illuminate, test the MIL control circuit for an open or high resistance. If the MIL control circuit tests OK, replace the IPC. If the MIL does illuminate, but does not when commanded ON with a scan tool, replace the ECM.
IMPORTANTAlways perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Scan Tool Data List

  1. Crank the engine for up to 30 seconds.
  2. Observe the Engine DTC information with a scan tool. If any of the following DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(ref-241670-S33247835882006081100000) to diagnose those DTCs: P0201-P0206, P0335, P0336, P0351-P0353, P0601, P0602, P0603, P0604, P0606, P0607, P060D, P062F, P0685, P0689, P0690, P1516, P2610
  3. Observe the engine speed parameter while cranking the engine. If engine RPM is not indicated, refer to «Electronic Ignition (EI) System Diagnosis»(ref-241724-S31165460522006081100000) .
  4. Install a spark tester.
  5. Crank the engine for 15 seconds. Spark should be observed from the Spark Tester. If spark is not observed refer to «Electronic Ignition (EI) System Diagnosis»(ref-241724-S31165460522006081100000) .
  6. With the ignition ON and the engine OFF, test the fuses that are supplied by the powertrain relay for voltage. The test lamp should illuminate at each test point for the following fuses: Emission Fuse Ignition 1 Fuse If the test lamp does not illuminate on at least one side of each fuse, refer to «DTC P0685, P0689 or P0690»(ref-241738-S05183130912006081100000) .
  7. Command the fuel pump ON and OFF. Fuel pump should energize when commanded ON and De-energize when commanded OFF If the fuel pump does not respond refer to «Fuel Pump Electrical Circuit Diagnosis»(ref-241724-S22717874872006081100000) .
  8. Turn OFF the ignition.
  9. Install the J 34730-1A Fuel Pressure Gage. Turn ON the ignition and command the fuel pump ON while observing the J 34730-1A . The fuel pressure should be between 345-414 kPa (50-60 psi). If the fuel pressure is not within 345-414 kPa (50-60 psi) refer to «Fuel System Diagnosis»(ref-241724-S11039114732006081100000) .
  10. Inspect for the following conditions: Compare the actual engine coolant temperature to the ECT parameter. Air filter and air intake system for restrictions and obstructions Test the fuel for contamination. Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(ref-241724-S06850347672006081100000) . Inspect the spark plug and spark plug wires. Refer to «SPARK PLUG WIRE INSPECTION»(ref-241687-S38996683812007030600000) . Test the exhaust system for restrictions. Refer to «Restricted Exhaust»(ref-241745-S18134174622006081100000) .

Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Battery Voltage - Relay Switch Side12
Fuel Pump Supply Voltage123
Fuel Pump Relay ControlP0230P0230P0230
Fuel Pump Relay GroundP0230P0230P0230
Fuel Pump Ground2
1 Open fuel pump fuse, cranks no start 2 Cranks no start 3 Fuel pump operates continuously, then discharged battery

Fuel Pump Electrical Circuit Diagnosis

Diagnostic Aids

The following conditions may cause the fuel pump fuse to open

  1. The fuse is faulty.
  2. There is an intermittent short to ground in the supply voltage circuit of the fuel pump.
  3. The fuel pump has an intermittent internal condition.
  1. «Scan Tool Data List»(ref-241748-S22574443422006081100000)
  2. «Scan Tool Data Definitions»(ref-241748-S27313933292006081100000)
  3. «Scan Tool Output Controls»(ref-241748-S22193935662006081100000)
  1. With the ignition OFF, remove the fuel pump relay from the rear electrical center.
  2. With the ignition ON, engine OFF, probe the control circuit of the fuel pump relay with a test lamp that is connected to a good ground. Command the fuel pump relay ON and OFF with a scan tool. The test lamp should turn ON and OFF with each command. If the test lamp does not turn ON and OFF, test for an open or a short to ground in the fuel pump relay control circuit, an intermittent or a poor connection at the engine control module (ECM) or a faulty ECM. If the test lamp remains illuminated with each command, test for a short to voltage in the control circuit of the fuel pump relay, an intermittent or a poor connection at the ECM or a faulty ECM.
  3. Connect a test lamp between the control circuit of the fuel pump relay and the ground circuit of the fuel pump relay. Command the fuel pump relay ON and OFF with a scan tool. If the test lamp does not turn ON and OFF, repair the open or the high resistance in the ground circuit of the fuel pump relay. If the test lamp does turn ON and OFF, test for an intermittent and for a poor connection at the fuel pump relay or a faulty fuel pump relay.
  4. Inspect the fuel pump fuse. If the fuel pump fuse is open, test for a short to ground in the supply voltage circuit of the fuel pump or a faulty fuel sender.
  5. With the ignition ON, engine OFF, probe the battery positive voltage circuit of the fuel pump relay with a test lamp that is connected to a good ground. If the test lamp does not illuminate, repair the open in the battery positive voltage circuit.
  6. Connect a 15-amp fused jumper wire between the battery positive voltage circuit of the fuel pump relay and the supply voltage circuit of the fuel pump. If the fuel pump operates, test for an intermittent or poor connection at the fuel pump relay or a faulty fuel pump relay. If the fuel pump does not operate, test for an open or high resistance in the supply voltage circuit of the fuel pump, an open or high resistance in the ground circuit of the fuel pump, an intermittent or poor connection at the fuel sender cover or a faulty fuel sender.

Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

  1. «Scan Tool Data List»(ref-241748-S22574443422006081100000)
  2. «Scan Tool Data Definitions»(ref-241748-S27313933292006081100000)
  3. «Scan Tool Output Controls»(ref-241748-S22193935662006081100000)

Testing Procedure

  1. Turn OFF the ignition.
  2. Relieve the fuel pressure. Refer to «FUEL PRESSURE RELIEF»(ref-241687-S25790378692007030600000) ..
  3. Disconnect the chassis fuel hose from the engine compartment fuel pipe. Refer to «FUEL HOSE/PIPES REPLACEMENT - CHASSIS»(ref-241687-S40730260922007030600000) .
  4. Install the J 37287 between the chassis fuel hose and the engine compartment fuel pipe. See «Special Tools»(ref-241687-S04860103302006081100000) .
  5. Open the valve on the J 37287 . See «Special Tools»(ref-241687-S04860103302006081100000) .
  6. Turn ON the ignition, with the engine OFF.
  7. Command the fuel pump relay ON with a scan tool.
  8. Bleed the air from the J 34730-1A .
  9. Command the fuel pump relay ON and then OFF with a scan tool.
  10. Close the fuel feed pipe shut-off valve.
  11. Monitor the J 34730-1A for 1 minute. If the fuel pressure remains constant, replace the fuel sender assembly. If the fuel pressure does not remain constant, locate and replace the leaking fuel injectors.

Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

  1. Monitoring the misfire current counters or misfire graph, may help to isolate the fuel injector that is causing the condition.
  2. Operating the vehicle over a wide temperature range may help isolate the fuel injector that is causing the condition.
  3. Perform the fuel injector coil test within the conditions of the customers concern. A fuel injector condition may only be apparent at a certain temperature or under certain conditions.
  1. «Scan Tool Data List»(ref-241748-S22574443422006081100000)
  2. «Scan Tool Data Definitions»(ref-241748-S27313933292006081100000)
  3. «Scan Tool Output Controls»(ref-241748-S22193935662006081100000)

Fuel Injector Coil Test

  1. Observe the ECT Sensor parameter with a scan tool. The ECT sensor should be 10-32°C (50-90°F). If the ECT Sensor parameter is not within 10-32°C (50-90°F), go to step 3.
  2. Measure the resistance of each fuel injector with a DMM. The resistance of each fuel injector should be 11-14 ohms. If the resistance of any fuel injector is not 11-14 ohms, replace the fuel injector.
  3. Measure and record the resistance of each fuel injector with a DMM. Subtract the lowest resistance value from the highest resistance value. The difference between the lowest value and the highest value should be equal to or less than 3 ohms. If the difference is equal to or less than 3 ohms, perform the Fuel Injector Balance Test-Fuel Pressure Test. If the difference is more than 3 ohms, continue with the Fuel Injector Coil Test.
  4. Add all of the fuel injector resistance values to obtain a total resistance value. Divide the total resistance value by the number of fuel injectors to obtain an average resistance value. Subtract the lowest individual fuel injector resistance value from the average resistance value. Compute the difference between the highest individual fuel injector resistance value and the average resistance value. Replace the fuel injector that displays the greatest resistance difference above or below the average.
  5. Perform the Fuel Injector Balance Test-Fuel Pressure Test.

Fuel Injector Balance Test-Fuel Pressure Test

IMPORTANTDO NOT perform this test if the engine coolant temperature (ECT) is above 94°C (201°F). Irregular fuel pressure readings may result due to hot soak fuel boiling.
IMPORTANTVerify that adequate fuel is in the fuel tank before proceeding with this diagnostic.
  1. Install a fuel pressure gage. Refer to «FUEL PRESSURE GAGE INSTALLATION AND REMOVAL»(ref-241687-S07442735162007030600000) .
  2. Turn ON the ignition, with the engine OFF.
  3. Command the fuel pump relay ON with a scan tool.
  4. Observe the fuel pressure gage with the fuel pump commanded ON. The fuel pressure should be 345-414 kPa (50-60 psi). If the fuel pressure is not 345-414 kPa (50-60 psi), refer to «Fuel System Diagnosis»(ref-241724-S11039114732006081100000) .
  5. Monitor the fuel pressure gage for one minute. The fuel pressure should not decrease more than 34 kPa (5 psi). If the fuel pressure decreases more than 34 kPa (5 psi), refer to «Fuel System Diagnosis»(ref-241724-S11039114732006081100000) .
  6. Perform the Fuel Injector Balance Test with Special Tool or the Fuel Injector Balance Test with Tech 2.

Fuel Injector Balance Test with Special Tool

  1. Set the amperage supply selector switch on the fuel injector tester to the Balance Test 0.5-2.5 amp position.
  2. Connect the J 39021 , the J 39021-210 and the J-39021-450 to the fuel injector multi-way connector. See «Special Tools»(ref-241687-S04860103302006081100000) .
  3. Command the fuel pump relay ON and then OFF with a scan tool.
  4. Record the fuel pressure indicated by the fuel pressure gage after the fuel pressure stabilizes. This is the first pressure reading.
  5. Energize the fuel injector by depressing the Push to Start Test button on the fuel injector tester.
  6. Record the fuel pressure indicated by the fuel pressure gage after the fuel injector has stopped pulsing. This is the second pressure reading.
  7. Repeat steps 2-6 for each fuel injector.
  8. Perform the Pressure Drop Calculation.

Fuel Injector Balance Test with Tech 2

  1. With a scan tool, select the Fuel Injector Balance Test function within the Special Functions menu.
  2. Select an injector to be tested.
  3. Press Enter to prime the fuel system.
  4. Record the fuel pressure indicated by the fuel pressure gage after the fuel pressure stabilizes. This is the first pressure reading.
  5. Energize the fuel injector by depressing the Pulse Injector button on the scan tool. This will energize the injector and decrease the fuel pressure.
  6. Record the fuel pressure indicated by the fuel pressure gage after the fuel injector has stopped pulsing. This is the second pressure reading.
  7. Press Enter again to bring you back to the Select Injector screen.
  8. Repeat steps 2-7 for each fuel injector.
  9. Perform the Pressure Drop Calculation.

Alcohol in Fuel Testing with Special Tool

  1. Test the fuel composition using J 44175 and Instruction Manual.
  2. If water appears in the fuel sample, clean the fuel system.
  3. Subtract 50 from the reading on the DMM in order to obtain the percentage of alcohol in the fuel sample.
  4. If the fuel sample contains more than 15 percent ethanol, add fresh, regular gasoline to the vehicle's fuel tank.
  5. Test the fuel composition.
  6. If testing shows the ethanol percentage is still more than 15 percent, replace the fuel in the vehicle.

Alcohol in Fuel Testing without Special Tool

  1. Using a 100 ml (3.38 oz) specified cylinder with 1 ml (0.034 oz) graduation marks, fill the cylinder with fuel to the 90 ml (3.04 oz) mark.
  2. Add 10 ml (0.34 oz) of water in order to bring the total fluid volume to 100 ml (3.38 oz) and install a stopper.
  3. Shake the cylinder vigorously for 10-15 seconds.
  4. Carefully loosen the stopper in order to release the pressure.
  5. Re-install the stopper and shake the cylinder vigorously again for 10-15 seconds.
  6. Put the cylinder on a level surface for approximately 5 minutes in order to allow adequate liquid separation. If alcohol is present in the fuel, the volume of the lower layer, which would now contain both alcohol and water, will be more than 10 ml (0.34 oz). For example, if the volume of the lower layer is increased to 15 ml (0.51 oz), this indicates at least 5 percent alcohol in the fuel. The actual amount of alcohol may be somewhat more because this procedure does not extract all of the alcohol from the fuel.

Particulate Contaminants in Fuel Testing Procedure

  1. Using an approved fuel container, draw approximately 0.5 liter (0.53 qt) of fuel.
  2. Place the container on a level surface for approximately 5 minutes in order to allow settling of the particulate contamination. Particulate contamination will show up in various shapes and colors. Sand will typically be identified by a white or light brown crystals. Rubber will appear as black and irregular particles.
  3. Observe the fuel sample. If any physical contaminants or water are present, clean the fuel system.
IMPORTANTAlways perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Inspect the spark plug wires for proper orientation.

  1. With the ignition OFF, remove the fuel pump relay using the J 43244 .
  2. Crank the engine and test for a strong spark on each cylinder spark plug wire using the J 26792 . Ground the companion cylinder spark plug wire of each cylinder when it is tested. If a strong bright blue spark is present on all 6 of the cylinders, remove and inspect all of the spark plugs for proper torque, proper gap, wear, damage and fouling. Refer to «SPARK PLUG REPLACEMENT»(ref-241687-S07054642802007030600000) , «SPARK PLUG INSPECTION»(ref-241687-S09794785642007030600000) and «Ignition System Specifications»(ref-241687-S24517631502006081100000) . Replace the spark plugs if necessary. If there is no spark on any of the cylinders, test the ignition voltage circuit of the ICM for an open/high resistance or short to ground or test the ground circuit of the ICM for an open/high resistance or a faulty ICM. The wire circuit resistance should measure less than 3 ohms. If spark is present on one or more of the cylinders, inspect and test the spark plug wires for arching, cuts, rubbing on other components and proper resistance, refer to «SPARK PLUG WIRE INSPECTION»(ref-241687-S38996683812007030600000) and «Ignition System Specifications»(ref-241687-S24517631502006081100000) or a faulty ICM. If all tests are normal, then the system is operating correctly.

Component Testing

  1. With positive polarity to the low reference terminal, measure for 9,000-11,000 ohms at 20-23°C (68-74°F) room temperature between each of the ignition coil control terminals and the low reference terminal of the ICM. If the resistance is not within the specified range, replace the ICM.
  2. Measure for 7,000-15,000 ohms at 20-23°C (68-74°F) room temperature between each pair of coil towers on the ICM. If the resistance is not within the specified range, replace the ICM.
IMPORTANTAlways perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  1. Observe the Engine DTC information with a scan tool. If a DTC is set that would prevent the I/M System Status tests from completing, diagnose that DTC before continuing. Refer to «Inspection/Maintenance (I/M) System DTC Table»(ref-241724-S19139280692006081100000) .
  2. Review applicable service bulletins for software updates that would prevent the I/M System Status tests from completing. If a control module re-program or other repair is required, perform the «Inspection/Maintenance (I/M) Complete System Set Procedure»(ref-241724-S31697531722006081100000) .
  3. Observe the I/M System Status indicators. If any I/M System Status indicators report NO, perform the «Inspection/Maintenance (I/M) Complete System Set Procedure»(ref-241724-S31697531722006081100000) .
IMPORTANTAlways perform the Inspection/Maintenance (I/M) System Check prior to using this diagnostic procedure.

Inspection/Maintenance (I/M) System Set Procedure

  1. Ensure that the vehicle meets the conditions for a cold start listed above. If the evaporative emission (EVAP) I/M System Status indicator displays NO, perform the EVAP Service bay test if applicable. If the EVAP Service bay test is NOT available, it may take up to 6 drive cycles, with 17 hours between drive cycles for the EVAP I/M System Status Indicator to transition to YES. The EVAP I/M System Status indicator requires several drive and 17 hour key OFF cycles to complete before the indicator will transition. If the O2S Heater System Status indicator displays NO, ensure that the ignition has been turned OFF for at least 10 hours.
  2. Turn OFF all accessories, HVAC system, other electrical loads, including aftermarket/add-on equipment, etc. and open the hood.
  3. Set the vehicle parking brake and ensure the vehicle is in park for automatic transmission or neutral for manual transmission.
  4. Turn the ignition ON with the engine OFF for 1 minute.
  5. Start and idle the engine for 2 minutes and until 65°C (149°F) is achieved.
  6. Run the engine for 6.5 minutes within the following conditions: MAF parameter between 4-30 g/s Engine speed steady between 1,000-3,000 RPM
  7. Return the engine to idle for 1 minute.
  8. Apply and hold brake pedal and shift to Drive for automatic or apply clutch pedal for manual and operate the vehicle within the following conditions for 2 minutes: Depress the accelerator pedal until throttle position (TP) sensor angle is more than 2 percent. Mass air flow (MAF) signal between 15-30 g/s RPM steady between 1200-2000 RPM
  9. Release the accelerator pedal and shift the vehicle to Park for automatic or Neutral and release clutch pedal for manual and allow the engine to idle for 2 minutes.
  10. Quickly depress the accelerator pedal until TP Sensor Angle is more than 8 percent and return to idle, repeat 3 times.
  11. Allow engine to idle for at least 2 minutes.
  12. Close the hood, release the parking brake and drive vehicle at 24 km/h (15 mph) or slower for 2 minutes.
  13. Continue to drive the vehicle for at least 5.5 miles between 45-112 km/h (28-70 mph) with the vehicle reaching at least 80 km/h (50 mph).
  14. Release the accelerator pedal for at least 3 seconds. This will allow the vehicle to enter the decel fuel cut off.
  15. Depress the accelerator pedal until the TP Sensor angle is between 3-20 percent and maintain for 1 minute.
  16. Safely stop the vehicle, with the engine in drive for automatic or neutral with the clutch pedal depressed and parking brake applied for manual. Allow the vehicle to idle for 2 minutes.
  17. Shift the vehicle to park for automatic and neutral for manual. Turn OFF the ignition and exit the vehicle. Do NOT disturb the vehicle for 45 minutes.
  18. Observe the I/M System Status with a scan tool. All of the I/M System Status indicators should display YES. If the EVAP I/M System Status indicator displays NO turn OFF the ignition for 17 hours, ensure that the vehicle meets the conditions for a cold start and repeat steps 13-18 three more times or until the EVAP I/M System Status indicator transitions to YES. If the indicator continues to display NO, refer to the «Inspection/Maintenance (I/M) System DTC Table»(ref-241724-S19139280692006081100000) to identify the DTCs that did not run.
  1. If any of the I/M System Status indicators display NO, refer to the «Inspection/Maintenance (I/M) System DTC Table»(ref-241724-S19139280692006081100000) for the indicator which did not display YES. The I/M System DTC Table identifies the DTCs associated with each I/M System Status Indicator.

Inspection/Maintenance (I/M) System DTC Table

SystemDTCs Required to Set System Status to YES
If an I/M System Status indicator did NOT update to YES during the Inspection/Maintenance (I/M) Complete System Set Procedure , review each indicator and reference this table to determine each DTC associated with the I/M System Status Indicator. Each DTC listed below has specific conditions that must be met for the diagnostic to run. Included within the conditions are additional DTCs which, if set, may inhibit the DTCs listed below from running. Reviewing and operating the vehicle within the Conditions for Running for each DTC listed below will allow the I/M System Status Indicators to transition to YES.
Catalyst MonitorDTC P0420-Refer to DTC P0420 .
Evaporative Emission (EVAP)DTC P0442-Refer to DTC P0442 . DTC P0446-Refer to DTC P0446 . DTC P0455-Refer to DTC P0455 . DTC P0496-Refer to DTC P0496 .
Oxygen SensorDTC P0140-Refer to DTC P0137, P0138 or P0140 . DTC P1133-Refer to DTC P0133, P1133 or P2A00 . DTC P2A01-refer to DTC P2A01 .
Oxygen Sensor HeaterDTC P0135-Refer to DTC P0030, P0053 or P0135 . DTC P0141-Refer to DTC P0036, P0054 or P0141 .

Inspection/Maintenance (I/M) System DTC Table

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