GM Service Manual Online
For 1990-2009 cars only

Symptom

Procedure

The ignition key cannot be removed from the lock cylinder with the gear selector in PARK.

Lock Cylinder Can Be Removed Without Depressing Retainer

The gear selector does not shift out of PARK with the brake pedal depressed and the ignition switch in RUN.

Automatic Transmission Shift Lock Control Always On with Ignition in Run

The gear selector shifts out of PARK with the ignition switch in RUN and the brake pedal not depressed.

Automatic Transmission Shift Lock Control Inoperative

The gear selector shifts out of PARK with the ignition switch in OFF (with center console only)

Test CKT 275 for a short to battery voltage or for a faulty transaxle range switch. If OK, replace the automatic transaxle control.