GM Service Manual Online
For 1990-2009 cars only

Important: Review the system description in order to familiarize yourself with the system functions. Refer to Automatic Transmission Shift Lock Control Circuit Description .

Visual/Physical Inspection

    • Inspect for aftermarket devices which could affect the operation of the Automatic Transmission Shift Lock Control System. Refer to Checking Aftermarket Accessories in Wiring Systems.
    • Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Symptom List

Refer to a symptom diagnostic procedure from the following table in order to diagnose the symptom:

Step

Action

Normal Result(s)

Abnormal Result(s)

1

  1. Turn ON the ignition, with the engine OFF.
  2. Depress the brake pedal.
  3. Attempt to move the shift lever out of the PARK position.

The transmission shift lever will move out of the PARK position.

Automatic Transmission Shift Lock Control Always On with Ignition in Run

2

  1. Shift to the PARK position.
  2. Release the brake pedal.
  3. Block the wheels.
  4. Attempt to move the shift lever out of the PARK position.

The transmission shift lever will not shift out of the PARK position.

Automatic Transmission Shift Lock Control Inoperative

Refer to the appropriate symptom diagnostic table for further diagnosis.