Engine Vibration/Noise at Idle, Vibration Felt in Steering Wheel/Seat (Reprogram PCM)

Some customers may comment on an engine vibration or noise while the vehicle is in gear at idle. This vibration can be felt in the steering wheel or seat and may intensify if the A/C is turned on. It should be noted that if the engine speed is raised or lowered approximately 50 RPMs, the vibration/noise will be reduced or go away.

A new service calibration has been released to lower the engine idle speed to 538 RPM in park/neutral and 525 RPM in gear. Before installing the new calibration, use the Tech 2® and go into Powertrain/Special Functions/TAC System/Engine Speed Control and when the condition is duplicated (engine running, in gear, foot on the brake, A/C on), command the idle down to 525 RPM. If the condition greatly improves or goes away, reprogram the PCM with the updated software calibration. This new calibration was released with TIS satellite data update version 1.75 available January 26, 2005. As always, make sure your Tech 2® is updated with the latest software version.

Also, if the vehicle is a 2004 model, Corporate Bulletin Number 04-06-01-023 may need to be performed.

For vehicles repaired under warranty, use:

*This is a unique labor operation number for use only with this bulletin. This number will not be published in the Labor Time Guide.