GM Service Manual Online
For 1990-2009 cars only

Step

Action

Normal Result(s)

Abnormal Result(s)*

1

With the ignition in the RUN position, depress the brake pedal.

Transmission will shift from the park position.

Automatic Transmission Shift Lock Control Diagnosis (Transmission Will Not Shift)

2

Place the ignition in the OFF position and release the brake pedal.

Transmission will not shift from the park position.

Automatic Transmission Shift Lock Control Diagnosis (Transmission May Be Shifted)

* Refer to the appropriate symptom diagnostic table for the applicable abnormal result.