GM Service Manual Online
For 1990-2009 cars only
  1. Warm the engine to normal operating temperature - until the radiator fan turns on.
  2. Apply the parking brake and block both rear wheels.
  3. Start the engine, and shift to the D position, while pressing the brake pedal.
  4. Press the accelerator pedal, and release it suddenly. The engine should not stall.
  5. Repeat step 2-4 in all shift lever positions.
  6. Connect the scan tool.
  7. Test-drive the vehicle on a flat road in the D position.
  8. Listen for abnormal noise and clutch slippage.
  9. While driving, check that shift points occur at the proper speeds, by monitoring the throttle position sensor voltage with the scan tool. Compare your shift point speeds and voltage to those in Shift Speed. Refer to Shift Speed .