GM Service Manual Online
For 1990-2009 cars only

Your vehicle has an automatic transmission shift lock control system. You have to fully apply the regular brakes before you can shift from PARK (P) when the ignition is in RUN. See Automatic Transmission Operation .

If you cannot shift out of PARK (P), ease pressure on the shift lever-push the shift lever all the way into PARK (P) as you maintain brake application. Then move the shift lever into the gear you want. You must press the shift lever button on the shift lever.

If you ever hold the brake pedal down but still can't shift out of PARK  (P), try this:

  1. Turn the key to OFF.
  2. Apply and hold the brake until the end of Step 4.
  3. Shift the transmission to NEUTRAL (N).
  4. Start the vehicle and then shift to the drive gear you want.
  5. Have the vehicle fixed as soon as possible.