Engine Controls - Low Speed Throttle Tip-In Clunk Noise

Bulletin No.: 05-06-04-017

Date: March 07, 2005

TECHNICAL

Subject:
Throttle Tip-in Clunk Noise at Low Speeds (Reprogram ECM)

Models:
2005 Buick Rainier
2005 Chevrolet TrailBlazer Models
2005 GMC Envoy Models

with 5.3L Gasoline Engine (VIN M - RPO LH6)

Condition

Some customers may comment on a clunk type noise on light throttle tip-in at low speeds. The clunk type noise may be evident but not as significant at higher speeds.

Cause

Torque reversal in the driveline may cause this condition. Engineering made Calibration changes to increase air flow during a decel to help keep a positive driveline torque. These air flow changes also drive changes to the cruise control operation.

Correction

Reprogram the ECM with calibration P/N 12597129 or P/N 12597130 using the appropriate Service Information (SI) procedures. The new calibrations were released beginning with TIS satellite data update version 11 for 2004, available November 2004. As always, make sure your TECH 2(R) is updated with the latest software version.





Warranty Information





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