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 Inoperative

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 Always On with Ignition in Run

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