Montana SV6 V6-3.9L (2007)
Control Module: Technical Service Bulletins
A/T - Intermittent Harsh Upshifts/Downshifts DTC P1811
TECHNICAL
Bulletin No.: 09-07-30-013A
Date: August 06, 2009
Subject: Intermittent Harsh Upshifts or Downshifts, DTC P1811 (Maximum Adapt and Long Shift) (Reprogram TCM)
Models:
2005-2008 Buick LaCrosse/Allure
Equipped with 3.6L Engine (RPO LY7) and 4T65 Automatic Transmission (RPO M15)
2007 Buick Terraza
2007-2009 Chevrolet Uplander
2007-2009 Pontiac Montana
2007 Saturn Relay
Equipped with 4T65 Automatic Transmission (RPO M15 or M76)
Supercede:
This bulletin is being revised to change the labor time information. Please discard Corporate Bulletin Number 09-07-30-013 (Section 07 -
Transmission/Transaxle).
Condition
Some customers may comment on harsh or firm upshifts or downshifts. These conditions may be intermittent. Diagnosis may indicate that DTC P1811
(Maximum Adapt and Long Shift) has been set. This condition may also include intermittent harsh upshifts at low speeds when lifting out of throttle, and
harsh downshifts at 2-1 coast down, or harsh shifts when rolling to a stop and stepping into the throttle before completely stopped.
Cause
These conditions may be caused by the TCM setting a DTC P1811. This may not be observable on the Tech 2(R). With a P1811, the SES light is not
illuminated, but the transmission defaults to maximum line pressure. While the code is active and at maximum line pressure, all shifts may be harsh
including upshifts, downshifts and shifts out of PARK. When the code is not active, most shifts may seem normal. However, the customer may comment
on intermittent harsh upshifts and harsh downshifts, and a delay with harsh shifts when rolling to a stop and stepping into throttle before completely
stopped.
Correction
An updated TCM calibration has been developed to address this condition. If the Service Information for the conditions described above do not isolate a
fault, reprogram the TCM with the latest calibration available. Verify that the multiple diagnostic interface (MDI) that is being used is configured to the
PC that will be used.
Important
Confirm the newest calibration includes the following description: "Select this calibration only to address DTC P1811 (Maximum Adapt and
Long Shift), Harsh Upshifts, or Downshifts." This calibration should only be used to repair vehicles that have the subject condition. This
calibration, or any that follow, is designed to address this concern. Use of this calibration to attempt to fix other conditions will not be
successful and are subject to warranty claim review.
Note
Reprogram the TCM with the software now available in the TIS2WEB using the Service Programming System (SPS). 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) Diagnostic Scan Tool is updated
with the latest software version. Clear any codes and verify the condition has been fixed.
Warranty Information
For vehicles repaired under warranty, use the table above.
