GM Service Manual Online
For 1990-2009 cars only

Step

Action

Normal Result(s)

Abnormal Result(s)*

1

  1. Make sure the gearshift selector into the PARK position.
  2. Turn the ignition switch to the RUN position.
  3. Depress the brake pedal and hold.
  4. Move the gearshift selector to the NEUTRAL position.

Brake transmission interlock solenoid disengages and allows driver to move gearshift selector from PARK to NEUTRAL.

Automatic Transmission Shift Lock Control Always On With Ignition in RUN

2

  1. Depress the brake pedal and hold.
  2. Place the gearshift selector into the PARK position.
  3. Remove all foot pressure from the brake pedal.
  4. Attempt to move the gearshift selector from PARK to the NEUTRAL position.

Gearshift selector does not move from the PARK position.

Automatic Transmission Shift Lock Control Inoperative

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