| Subject: | Harsh Garage Shift Cold |
| Models: | 1999-2005 Buick Century, LeSabre, Park Avenue, Regal, Rendezvous |
| 2005-2007 Buick Allure (Canada), LaCrosse, Lucerne, Rendezvous, Terraza, |
| 2000-2005 Chevrolet Impala, Monte Carlo. Venture |
| 2006-2007 Chevrolet Impala, Malibu, Monte Carlo, Uplander |
| 1999-2002 Chevrolet Lumina |
| 1999-2002 Oldsmobile Aurora, Intrigue |
| 1999-2004 Oldsmobile Silhouette |
| 1999-2005 Pontiac Bonneville, Grand Prix, Montana |
| 2006-2007 Pontiac G6, Grand Prix, Montana |
This PI was updated to include 2006 and 2007 model years. Please discard PIP3460.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
The 4T65E Automatic Transmission may exhibit a condition of a harsh garage shift into reverse or drive on a cold start. The condition will typically occur on the first start of the day and will not reoccur until the vehicle has an overnight soak. The
harsh garage shift occurs due to an elevated idle of 1,100 to 1,300 (approximate) RPM and a commanded amperage of 0.1 amps (approximate). Once the engine RPM reduces to a normal idle speed 650 to 800 (approximate), the transmission engagement becomes smoother.
Recommendation/Instructions:
Due to the emission package on the vehicle, the idle may be elevated during the first 30 to 60 seconds (approximate) on a cold start. The condition should be considered characteristic and should be compared to a like unit with the same emission package.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
