GM Service Manual Online
For 1990-2009 cars only

Important: 

   • The following procedure is for vehicles that have not had the park/neutral position (PNP) switch removed or replaced. If the switch has been removed or replaced, refer to Park/Neutral Position Switch Replacement for the proper adjustment procedure.
   • Apply the park brake.
   • The engine must start in the park (P) or neutral (N) positions only.
   • Check the PNP switch for proper operation. If adjustment is required, proceed as follows:

  1. Place the shift lever in the neutral (N) position.
  2. With an assistant in the drivers seat, raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle .
  3. Loosen the PNP switch bolts.
  4. With the vehicle in neutral (N), rotate the PNP switch while the assistant attempts to start the engine.
  5. Following a successful start, turn the engine OFF.
  6. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  7. Tighten the PNP switch bolts.
  8. Tighten
    Tighten the bolts to 25 N·m (18 lb ft).

  9. Lower the vehicle.
  10. Check the PNP switch for proper operation. The engine must start in the park (P) or neutral (N) positions only.
  11. Replace the PNP switch if proper operation can not be achieved. Refer to Park/Neutral Position Switch Replacement .