GM Service Manual Online
For 1990-2009 cars only

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.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Control

1

1

1

--

Ground

--

1

--

--

1. Park lever will not move from PARK with the brake pedal pressed.

Circuit/System Description

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

Reference Information

Schematic Reference

Shift Lock Control Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Automatic Transmission Shift Lock Control Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON, observe the scan tool Brake Applied Output Signal parameter while pressing and releasing the brake pedal. The parameter should change from ON to OFF when the brake pedal is depressed.
  2. If the parameter does not change, refer to Stop Lamps Malfunction.
  3. While pressing the brake pedal, observe the scan tool Brake Applied Output Signal parameter. The reading should be ON with the brake pedal pressed.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the shift lock actuator.
  2. Ignition OFF, test for less than 1.0 Ω between the ground circuit terminal and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Connect a test lamp between the ground circuit terminal and the control circuit terminal.
  5. Ignition ON, command the scan tool Shift Lock Solenoid Actuator ON and OFF. The test lamp should turn ON and OFF when changing between the commanded states.
  6. If the test lamp is always ON, test the control circuit for short to voltage. If the circuit tests normal, replace the body control module.
    If the test lamp is always OFF, test the control circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the body control module.
  7. If all circuits tests normal, test or replace the shift lock actuator.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Transmission Control Replacement
    •  Control Module References for ECM replacement, setup, and programming