GM Service Manual Online
For 1990-2009 cars only

Description

The engine control module (ECM) learns the idle position of the throttle body to ensure the correct idle operation. Anytime the ECM or the throttle body is replaced, the ECM must learn the idle position. The engine idle may be unstable or a DTC may set if the idle position is not learned.

Conditions for Running the Idle Learn Procedure

    • DTCs P0121, P0122, P0123, P0221, P0222, P0223, P0638, P2100, P2101, P2105, P2107, and P2119 are not set.
    • The engine speed is less than 40 RPM.
    • The vehicle speed is 0 km/h (0 mph).
    • The accelerator pedal position is less than 14.9 percent.
    • The ignition 1 voltage is more than 10 volts.
    • The engine coolant temperature is between 5-85°C (41-185°F).
    • The intake air temperature is between 5-60°C (41-140°F).

Idle Learn Procedure

    Important: 

       • Ensure the above conditions are met before proceeding with this procedure.
       • Do not perform this procedure if a throttle position (TP) sensor or other throttle actuator control (TAC) system DTCs are set other than P2176. The ECM will not perform the idle learn procedure with a DTC set.

  1. Turn OFF the ignition for 30 seconds.
  2. Turn ON the ignition, with the engine OFF for 60 seconds.
  3. Turn OFF the ignition.
  4. Turn ON the ignition, with the engine OFF.
  5. Clear the DTCs with a scan tool.