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Starter Solenoid Does Not Click



Starter Solenoid Does Not Click

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



Diagnostic Fault Information






Circuit/System Description

When the ignition mode switch is placed in the START position, a discrete signal is supplied to the body control module (BCM) notifying it that the ignition is in the START position. The BCM then sends a message to the engine control module (ECM) that crank has been requested. The ECM then verifies that the transmission is in Park or Neutral. If it is, the ECM then supplies a ground to the control circuit of the CRANK relay. When this occurs, battery voltage is supplied through the switch of the CRANK relay to S terminal of the starter solenoid.


Reference Information
Schematic Reference

Starting and Charging Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Starting System Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information


Circuit/System Verification

1. Ignition ON, verify that no brake pedal position sensor, starter relay, theft deterrent, or automatic transmission DTCs are set that would cause the ECM to disable starting.

• If DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code Descriptions) .

2. Ignition ON, observe the scan tool BCM Ignition Mode Switch parameter. Place the ignition mode switch in the crank position, the parameter should display CRANK.

• If not the specified value, refer to Power Mode Description and Operation (Power Mode Description and Operation) .

3. Transmission range selector in park , verify the scan tool ECM PNP Switch and TCM IMS parameters display Park/Neutral.

• If the TCM IMS parameter does not indicate Park/Neutral, refer to Transmission Internal Mode Switch Logic (Transmission Internal Mode Switch Logic) .


• If the ECM Park/Neutral parameter does not indicate Park/Neutral, refer to ECM Park Switch Circuit Malfunction.

4. Transmission range selector in park or neutral, attempt to start the vehicle. The starter relay should click and the engine should begin cranking.

• If the starter relay does not click or the engine does not crank, refer to Starter Relay Circuit Malfunction.




Circuit/System Testing


ECM Park Switch Circuit Malfunction (6L50/6L80/6L90-E)
1. Ignition OFF, disconnect the harness connector at the AT Inline 16-Way Connector.
2. Ignition ON, install a 3A fused jumper wire between the signal circuit terminal 3 and ground. Verify the scan tool ECM PNP switch parameter displays Park/Neutral.

• If not the specified value, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

3. If all circuits test normal, test or replace the internal mode switch (IMS).



Starter Relay Circuit Malfunction
1. Ignition OFF, disconnect the starter relay.
2. Ignition ON, verify a test lamp illuminates between the relay coil B+ circuit terminal C13 and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

3. Ignition ON, verify a test lamp illuminates between the relay switch B+ circuit terminal C14 and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

4. Connect a test lamp between the relay coil control circuit terminal A13 and the relay coil B+ circuit terminal C13.
5. With the transmission range selector in park or neutral and the brake pedal depressed, cycle the ignition mode switch between the OFF and START position. The test lamp should turn ON and OFF when changing between the commanded states.

• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.
• If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

6. Ensure the parking brake is applied and the transmission is in PARK. Momentarily install a 40A fused jumper wire between the B+ circuit terminal C14 and the control output circuit terminal A13. The starter solenoid should engage and the engine should begin cranking.

• If the solenoid does not engage, test the control output circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the starter motor.

7. If all circuits test normal, test or replace the starter relay.



Component Testing

1. Ignition OFF, disconnect the starter relay.
2. Test for 60-180 ohms between terminals 85 and 86.

• If the resistance is not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

* 30 and 86
* 30 and 87
* 30 and 85
* 85 and 87


• If not the specified value, replace the relay.

4. Install a 20A fused jumper wire between terminal 85 and 12 volts. Install a jumper wire between terminal 86 and ground. Test for less than 2.0 ohms between terminals 30 and 87.

• If greater than the specified range, replace the relay.




Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Relay Replacement (Attached to Wire Harness) (Relay Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (Relay Replacement (Within an Electrical Center))
* Manual Shift Shaft Position Switch Replacement (Service and Repair)
* Starter Motor Replacement (LC3) (Service and Repair)Starter Motor Replacement (LH2) (Service and Repair)
* Control Module References (Programming and Relearning) for ECM replacement, setup and programming


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