Transmission Control Lever Malfunction

Transmission Control Lever Malfunction

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

The body control module (BCM) controls the shift lock solenoid by providing battery voltage to the shift lock control solenoid. The BCM utilizes a smart driver to control the voltage supplied to the shift lock solenoid. The smart driver monitors the voltage and current flow of the control circuit.


Diagnostic Aids

* Use a scan tool to verify there are no brake pedal position sensor and/or transmission internal mode switch (IMS) DTCs set that could cause the BCM not to provide battery voltage to the A/T shift lock solenoid.
* If the automatic transmission shift lock control circuit is shorted to battery positive voltage, the A/T shift lock solenoid will be inoperative. The vehicle will shift out of PARK without depressing the brake pedal.



Reference Information
Schematic Reference

Shift Lock Control Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Automatic Transmission Shift Lock Control 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, while pressing the brake pedal, observe the scan tool Brake Applied Output Signal parameter. The reading should be ON with the brake pedal pressed.

• If not the specified parameter, refer to Stop Lamps Malfunction (Stop Lamps Malfunction).

2. Ignition ON, observe the scan tool BCM Shift Lock Solenoid Command parameter. The parameter should change from ON to OFF when the brake pedal is depressed.

• If not the specified parameter, replace the BCM.

3. Press the brake pedal, the vehicle operator should be able to move the shifter lever out of the park position.



Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the automatic transmission shift lock actuator.
2. Ignition OFF, test for less than 1.0 ohm between the ground circuit terminal A and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the control circuit terminal B and ground.
4. Ignition ON, command the scan tool BCM Shift Lock Solenoid output control ON and OFF. The test lamp should turn ON and OFF as commanded.

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

5. If all circuits test normal, test or replace the shift lock control solenoid.



Component Testing

1. Install a 10 A fused jumper wire between the control circuit terminal B and 12 volts. Install a jumper wire between the ground circuit terminal A and ground.
2. Listen for the solenoid to turn ON and OFF.

• If the function does not perform as specified, replace the shift lock control solenoid.




Repair Instructions

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

* Automatic Transmission Shift Lock Actuator Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming