Transmission Control Lever Malfunction

Transmission Control Lever Malfunction

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

With the ignition in the OFF or ACCY position, the park lock solenoid is de-energized and locks the shift lever in the park position. With the ignition in the ON position, voltage is supplied to the park lock solenoid. The park lock solenoid energizes through a permanent ground unlocking the shift lever.


With the ignition in the ON position, voltage is supplied to the stop lamp switch. Voltage flows through the normally closed contacts of the switch to the automatic transmission shift lock control solenoid. The automatic transmission shift lock control solenoid is permanently grounded. This energizes the automatic transmission shift lock control solenoid causing the transmission shift lever to be physically locked in the PARK position. When the brake pedal is depressed, the contacts in the stop lamp switch open de-energizing the automatic transmission shift lock control solenoid. This allows the shift lever to be move out of the PARK position.


Diagnostic Fault Information






Diagnostic Aids

If the automatic transmission shift lock control circuit is open, 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
Description and Operation

Automatic Transmission Shift Lock Control Description and Operation (Description and Operation)
Electrical Information Reference

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



Circuit/System Verification

Ignition OFF, the gear shift lever should be locked in the PARK position. When the brake pedal is pressed, the gear shift lever can now be moved to any gear selection.


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. Ignition ON, verify that a test lamp illuminates between the control circuit terminal B and ground.

• If the test lamp does not illuminate, test the park lock solenoid and A/T shift lock control solenoid control circuits for an open or short to ground. If all circuits test normal, test or replace the automatic transmission shift lock actuator.

4. Ignition ON, verify that a test lamp illuminates between the control circuit terminal E and ground.

• If the test lamp does not illuminate, test the A/T shift lock control solenoid control circuit for an open. If all circuits test normal, test or replace the stop lamp switch.

5. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal E and ground when the brake pedal is depressed.

• If the test lamp illuminates, test the A/T shift lock control solenoid control circuit for a short to voltage. If all circuits test normal, test or replace the stop lamp switch.

6. If all circuits test normal, test or replace the automatic transmission shift lock actuator.



Component Testing

1. Install a 10 A fused jumper wire from 12 volts to the automatic transmission shift lock actuator control circuit terminals B and E. Momentarily connect a jumper wire from ground to terminal A.
2. Listen for the solenoids to turn ON and OFF.

• If the function does not perform as specified, replace the automatic transmission shift lock actuator.




Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

* Automatic Transmission Shift Lock Actuator Replacement (Service and Repair)
* Stop Lamp Switch Replacement