GM Service Manual Online
For 1990-2009 cars only

Starter Solenoid Does Not Click 6.6L /8.1L

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description Automatic Transmission

When the Ignition switch is placed in the start position B+ is supplied to the coil side of the STARTER relay, the powertrain control module (PCM) / engine control module (ECM) also receives the 12 V signal that crank has been requested, The PCM/ECM verifies the vehicle is in PARK and conditions are acceptable for engine cranking, the PCM/ECM will then ground the control circuit of the STARTER relay. With STARTER relay closed B+ is supplied to the starter solenoid and the engine will begin cranking.

Circuit/System Description Manual Transmission

When the Ignition switch is placed in the start position and Clutch Start Switch closed (clutch pedal depressed) B+ is supplied to the coil side of the STARTER relay, the powertrain control module (PCM) / engine control module (ECM) also receives the 12 V signal that crank has been requested, The PCM/ECM verifies the clutch pedal is depressed and conditions are acceptable for engine cranking, the PCM/ECM will then ground the control circuit of the STARTER relay. With STARTER relay closed B+ is supplied to the starter solenoid and the engine will begin cranking

Reference Information

Schematic Reference

Starting and Charging Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Starting System Description and Operation

Electrical Information Reference

    •  Testing for Intermittent Conditions and Poor Connections
    •  Circuit Testing
    •  Wiring Repairs
    •  Connector Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Automatic Transmission

  1. Ignition ON, observe the scan tool PCM/ECM Crank Request Signal parameter. Place Ignition switch in the START position, the parameter should display Yes.
  2. If not the specified value refer to Crank Request Signal Malfunction.
  3. Ignition ON, transmission in Park or Neutral, verify the scan tool PNP Switch parameter reads Park/Neutral.
  4. If not the specified value refer to Park/Neutral Circuit Malfunction.
  5. Place Ignition switch in the START position, the starter solenoid should engage and the engine should crank.
  6. If the solenoid does not engage, refer to STARTER Relay Circuit Malfunction.

Manual Transmission

  1. Ignition ON, observe the scan tool PCM/ECM Crank Request Signal parameter. With the clutch pedal fully depressed place ignition switch in the START position, the parameter should display Yes.
  2. If not the specified value refer to Crank Request Signal Malfunction.
  3. Ignition ON, clutch pedal fully depressed, verify the scan tool Clutch Start Switch parameter reads Applied.
  4. If not the specified value refer to Clutch Start Switch Circuit Malfunction.
  5. Place Ignition switch in the START position, the starter solenoid should engage and the engine should crank.
  6. If the solenoid does not engage, refer to STARTER Relay Circuit Malfunction.

Circuit/System Testing

Crank Request Signal Malfunction

  1. Verify that STRTR fuse 11 / circuit breaker is not open.
  2. Remove the STRTR fuse 11 / circuit breaker from the IP fuse block 1.
  3. Place the ignition switch to the START position verify a test lamp illuminates between terminal K6 and ground.
  4. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance, between IP fuse block 1 terminal K6 and Ignition switch terminal D.
  5. If the circuit tests normal replace the Ignition switch.
  6. Install a 10 amp fused jumper in place of STRTR fuse 11 / circuit breaker.
  7. Ignition OFF, disconnect the harness connector at the PCM/ECM.
  8. With the clutch pedal fully depressed on Manual transmissions and PARK on Automatic Transmissions, place the Ignition switch to the START position verify a test lamp illuminates between the Clutch Start Switch/ Crank request Signal circuit X1 terminal 7 (6.6L) or X2 terminal 59 (8.1L) and ground.
  9. If the test lamp does not illuminate, test the circuit for a short to ground or an open/high resistance.
  10. If the circuit tests normal replace the PCM/ECM.

Park/Neutral Circuit Malfunction

  1. Ignition OFF, disconnect the harness connector at the AT Inline Connector.
  2. Install a 3A fused jumper wire between the ignition circuit terminal 18 and ground. Verify the scan tool PCM/ECM PNP Switch parameter reads Park/Neutral.
  3. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the PCM/ ECM.
  4. If all circuits test normal, test or replace the IMS switch.

Clutch Start Switch Circuit Malfunction

  1. Ignition OFF, disconnect the harness connector at the clutch start switch.
  2. Ignition ON, verify a test lamp illuminates between the ignition circuit terminal A and ground.
  3. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
  4. Verify the scan tool Clutch Start Switch parameter reads Released.
  5. If not the specified value, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the PCM/ECM.
  6. Install a 3A fused jumper wire between the ignition circuit terminal A and the signal circuit terminal B. Verify the scan tool Clutch Start Switch parameter reads Applied.
  7. If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the PCM/ECM.
  8. If all circuits test normal, replace the Clutch Start Switch.

STARTER Relay Circuit Malfunction

  1. Ignition OFF, disconnect the crank relay, test for 60-80 ohms of resistance between relay terminals 85 and 86.
  2. If not within the specified range, replace the STARTER relay.
  3. Ignition ON, transmission in Park/Neutral (automatic transmission) or clutch pedal depressed (manual transmission), place the ignition switch to the START position verify a test lamp illuminates between the relay coil B+ circuit terminal A7 and ground.
  4. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  5. Ignition ON, verify a test lamp illuminates between the relay switch B+ circuit terminal A9 and ground.
  6. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the IGN 1 fuse is open, test the relay controlled output circuit for a short to ground.
  7. Connect a test lamp between the relay coil B+ circuit terminal A7 and the relay coil control circuit terminal B9.
  8. Ignition ON, transmission in Park/Neutral (automatic transmission) or clutch pedal depressed (manual transmission), The test lamp should turn ON and OFF when changing between the commanded states.
  9. If the test lamp is always ON, test the relay coil control circuit for a short to ground. If the circuit tests normal, replace the PCM/ECM.
    If the test lamp is always OFF, test the relay coil control circuit for a short to voltage or and open/high resistance.If the circuit tests normal, replace the PCM/ECM.

    Important: The engine may begin to crank.

  10. Ensure the parking brake is applied and the transmission is in NEUTRAL on manual transmission or PARK on automatic transmission. Momentarily install a 40A fused jumper wire between the B+ circuit terminal A9 and the control output circuit terminal B7. The starter solenoid should engage and the engine should begin cranking.
  11. If the solenoid does not engage, test the control output circuit for a short to ground or an open/high resistance.
  12. If all circuits test normal, test or replace the starter.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Relay Replacement
    •  Starter Motor Replacement
    •  Ignition and Start Switch Replacement
    •  Clutch Pedal Position Switch Replacement
    •  Control Module References for PCM/ECM replacement, setup and programming

Starter Solenoid Does Not Click LF6 /LF8

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description Automatic Transmission

With the Ignition in the ON position, the ECM enables the ECM relay by grounding the control circuit of the ECM relay. With ECM relay closed, B+ is supplied to the coil side of the STARTER CUT relay.The ECM will ground the control circuit of the STARTER CUT relay based on information from the TCM (automatic transmission) that the vehicle is in PARK, and conditions are acceptable for engine cranking.With the STARTER CUT relay closed, ground is supplied to the control circuit of the STARTER relay. With the Ignition switch in the Start position 12V is supplied to the coil side of the STARTER relay and signals the ECM that CRANK has been requested. With the STARTER relay closed battery voltage is supplied to the starter motor and engine will begin cranking.

Circuit/System Description Manual Transmission

With the Ignition in the ON position, the ECM enables the ECM relay by grounding the control circuit of the ECM relay. With ECM relay closed, B+ is supplied to the coil side of the STARTER CUT relay. The ECM will ground the control circuit of the STARTER CUT relay when a clutch start signal is received, clutch closed and conditions are acceptable for engine cranking.With the STARTER CUT relay closed, ground is supplied to the control circuit of the STARTER relay. With the Ignition switch in the Start position 12V is supplied through the closed clutch switch (clutch pedal depressed) to the coil side of the STARTER relay and signals the ECM that CRANK has been requested. With the STARTER relay closed battery voltage is supplied to the starter motor and engine will begin cranking.

Reference Information

Schematic Reference

Starting and Charging Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Starting System Description and Operation

Electrical Information Reference

    •  Testing for Intermittent Conditions and Poor Connections
    •  Circuit Testing
    •  Wiring Repairs
    •  Connector Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Automatic Transmission

  1. Ignition ON, observe the scan tool ECM Crank Request Signal parameter. Place Ignition switch in the START position, the parameter should display Yes.
  2. If not the specified value refer to Crank Request Signal Malfunction.
  3. Ignition ON, transmission in Park or Neutral, verify the scan tool PNP Switch parameter reads Park/Neutral.
  4. If not the specified value refer to Park/Neutral Circuit Malfunction.
  5. Place Ignition switch in the START position, the starter solenoid should engage and the engine should crank.
  6. If the solenoid does not engage, refer to STARTER Relay Circuit Malfunction.

Manual Transmission

  1. Ignition ON, observe the scan tool ECM Crank Request Signal parameter. With the clutch pedal fully depressed place the Ignition switch in the START position, the parameter should display Yes.
  2. If not the specified value refer to Crank Request Signal Malfunction.
  3. Ignition ON, clutch pedal fully depressed, verify the scan tool Clutch Start Switch parameter reads Applied.
  4. If not the specified value refer to Clutch Start Switch Circuit Malfunction.
  5. Place Ignition switch in the START position, the starter solenoid should engage and the engine should crank.
  6. If the solenoid does not engage, refer to STARTER Relay Circuit Malfunction.

Circuit/System Testing

Crank Request Signal Malfunction

  1. Verify that IP fuse block 1 Circuit Breaker 1 is not open.
  2. Ignition ON, verify a test lamp illuminates between Ignition switch terminal B1 and ground.
  3. If the test lamp does not illuminate, test the Ignition circuit for a short to ground or an open/high resistance, between IP fuse block 1 Circuit Breaker 1 terminal and Ignition switch terminal B1.
  4. Place the Ignition switch to the START position verify a test lamp illuminates between Ignition switch terminal S and ground.
  5. If the test lamp does not illuminate, replace the Ignition switch.
  6. Ignition OFF, disconnect the harness connector at the ECM.
  7. With the clutch pedal fully depressed on Manual transmissions and PARK on Automatic Transmissions, place the Ignition switch to the START position verify a test lamp illuminates between the Clutch Start Switch/ Crank request Signal circuit X1 terminal 96 and ground.
  8. If the test lamp does not illuminate, test the circuit for a short to ground or an open/high resistance.
  9. If the circuit tests normal replace the ECM.

Park/Neutral Circuit Malfunction

  1. Ignition OFF, disconnect the harness connector at the AT Inline Connector.
  2. Install a 3A fused jumper wire between the ignition circuit terminal 18 and ground. Verify the scan tool ECM PNP Switch parameter reads Park/Neutral.
  3. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
  4. If all circuits test normal, test or replace the IMS switch.

Clutch Start Switch Circuit Malfunction

  1. Ignition OFF, disconnect the harness connector at the clutch start switch.
  2. Ignition ON, verify a test lamp illuminates between the ignition circuit terminal A and ground.
  3. If the test lamp does not illuminate, test the Ignition circuit for a short to ground or an open/high resistance.
  4. Verify the scan tool Clutch Start Switch parameter reads Released.
  5. If not the specified value, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the ECM.
  6. Install a 3A fused jumper wire between the Ignition circuit terminal A and the signal circuit terminal B. Verify the scan tool Clutch Start Switch parameter reads Applied.
  7. If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
  8. If all circuits test normal, replace the Clutch Start Switch.

STARTER Relay Circuit Malfunction

  1. Ignition OFF, disconnect the crank relay, test for 60-80 ohms of resistance between relay terminals 85 and 86.
  2. If not within the specified range, replace the STARTER relay.
  3. Ignition ON, transmission in Park/Neutral (automatic transmission) or clutch pedal depressed (manual transmission), place the Ignition switch to the START position verify a test lamp illuminates between the relay coil B+ circuit terminal 85 and ground.
  4. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  5. Ignition ON, verify a test lamp illuminates between the relay switch B+ circuit terminal 30 and ground.
  6. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  7. Connect a test lamp between the relay coil B+ circuit terminal 85 and the relay coil control circuit terminal 86.
  8. Ignition ON, transmission in Park/Neutral (automatic transmission) or clutch pedal depressed (manual transmission), the test lamp should turn ON and OFF when changing between the commanded states.
  9. If the test lamp is always ON, test the relay coil control circuit for a short to ground. If the circuit tests normal, replace the ECM.
    If the test lamp is always OFF, test the relay coil control circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the ECM.

    Important: The engine may begin to crank.

  10. Ensure the parking brake is applied and the transmission is in NEUTRAL on manual transmission or PARK on automatic transmission. Momentarily install a 40A fused jumper wire between the B+ circuit terminal A9 and the control output circuit terminal B7. The starter solenoid should engage and the engine should begin cranking.
  11. If the solenoid does not engage, test the control output circuit for a short to ground or an open/high resistance.
  12. If all circuits test normal, test or replace the starter.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Relay Replacement
    •  Starter Motor Replacement
    •  Ignition and Start Switch Replacement
    •  Clutch Pedal Position Switch Replacement
    •  Control Module References for ECM replacement, setup and programming