GM Service Manual Online
For 1990-2009 cars only

Anytime the engine control module (ECM) or the throttle body is replaced, the ECM must learn the idle position of the throttle body. The engine idle may be unstable when the idle position has not been learned.

Perform the following procedure in order to allow the ECM to learn the idle position:

  1. With a scan tool, verity that DTCs are not set.
  2. Turn OFF the ignition for 30 seconds.
  3. Turn ON the ignition, with the engine OFF for 30 seconds.
  4. Turn OFF the ignition.