Envoy 4WD V8-5.3L VIN M (2005)
PROM - Programmable Read Only Memory: Customer Interest
Engine Controls - Low Speed Deceleration Shudder
Bulletin No.: 06-06-04-056
Date: October 24, 2006
TECHNICAL
Subject:
LH6 Engine Low Speed Deceleration Shudder, Chuggle or Pulsation (Reprogram ECM)
Models:
2006 Buick Rainier
2006 Chevrolet TrailBlazer, TrailBlazer EXT
2006 GMC Envoy Denali, Envoy XL Denali
2006 Saab 9-7X
with 5.3L Vortec V8 Active Fuel Management Engine VIN M - RPO LH6)
and Two-Wheel Drive ONLY Vehicles with 4L60-E Automatic Transmission (PRO M30)
Attention:
The following service ECM calibration update may slightly increase fuel consumption and should only be used if the customer commented on the
shudder conditions outlined in this Service Bulletin. Most vehicles will never experience this shudder.
Condition
Some customers may comment on the following low speed deceleration shudder, chuggle or pulsation conditions:
Shudder feels like a brake pulsation and/or chuggle on deceleration from approximately 40 km/h (25 mph) to 24 km/h (15 mph).
Shudder will continue if brakes are released and the vehicle coasts in 40 km/h (25 mph) to 24 km/h (15 mph) speed range.
Shudder is significantly diminished or eliminated if A/C is "Off' due to reduced engine load.
Shudder is eliminated if vehicle is put in D3 mode, which disables 4 cylinder mode (4 cyl mode is permitted when trans is automatically in 3rd or 4th
gear, but disabled when PRNDL is placed in the 3rd position).
Selectable Service Calibration Number
Use this selectable service calibration Only for vehicles with low speed deceleration shudder, chuggle and/or pulsation experienced at high temperature
and low altitude. A slight increase in fuel consumption may occur.
Calibration 12614807 is selectable with 12606496. The title line states: "New calibration to address vehicle shudder during decel between 25 and 15
mph, feels like brake roughness. Should be used for complaint only as some loss of performance and fuel economy may occur".
Correction
Reprogram the ECM with the latest calibrations if the above concern is encountered. An updated ECM calibration is now available to address this
concern. This calibration, or any that follow, is designed to address this concern. Refer to Service Programming System (SPS) using the appropriate
Service Information (SI) procedures. The new ECM calibrations will be available to dealerships in TIS2Web (website version of TIS) version 10.0 for
2006 beginning 10/01/2006. If you cannot access the calibration, call the Techline Customer Support Center and it will be provided. As always, make
sure your Tech 2(R) is updated with the latest software version.
Warranty Information (excluding Saab U.S. Models)
