6L80 Automatic Transmission Delayed Engagement from PARK to DRIVE or PARK to REVERSE (Reprogram Transmission Control Module (TCM))

This bulletin is being revised with a new Drive procedure and change the Warranty Information. Please discard Corporate Bulletin Number 06-07-30-002 (Section 07 - Transmission/Transaxle).

Some customers may comment on a delayed engagement into Drive or Reverse when shifting from Park.

Tip
Normal Park/Neutral to Reverse or Drive engagement time will be in the vicinity of one and a half (1.5) seconds if the automatic transmission fluid (ATF) is above 0°C (32°F). When the ATF is colder than 0°C (32°F), the engagement time will become longer with the colder the transmission fluid.

A revised transmission calibration has been released to address this issue. Follow the service procedure below.

1. Reprogram the TCM with an updated software calibration released with TIS satellite data update version 1 on 01/09/06 or later. Refer to Transmission Control Module Programming and Setup in Vehicle Control Systems in SI.
2. Check and clear all DTCs that may have set as a result of the programming process.
3. Perform a drive procedure as detailed below.

Drive Procedure

•	Drive maneuvers should be performed at transmission oil temperatures of at least 40°C (104°F).

•	Transmission oil levels should be set properly before starting drive cycles.

•	Initial upshifts may have an erratic feel for the first several cycles. They should improve significantly with repeated maneuvers.

•	At the start of the drive cycles, no DTCs should be set in the ECM or TCM. The MIL should not be illuminated.

•	A drive cycle requires five light throttle accelerations to 40 km/h (25 mph) and five light throttle accelerations to 64 km/h (40 mph).

1.	From a complete stop, lightly accelerate at a relatively constant throttle pedal position up to 40 km/h (25 mph) or 64 km/h (40 mph).

2.	Bring the vehicle to a complete stop using the regular brakes.

3.	Repeat five times to 40 km/h (25 mph) and five times to 64 km/h (40 mph). Maneuvers can be performed in any combination.

Important: After performing the drive procedure, the Garage Shift Adapts must also be learned by following the procedure below.

4. With a scan tool or the DIC, ensure that the transmission temperature is 40°C (104°F) or higher.
5. With the engine at idle, shift from Reverse to Drive leaving the shift lever in Drive for three seconds. After three seconds, shift back to the Reverse position leaving the shift lever in Reverse for three seconds. Perform this procedure 20 times (R-D-R-D-R-D...). The transitions need to be directly to Drive and Reverse, without stopping in Neutral.
6. With the engine at idle, shift from Neutral to Drive leaving the shift lever in Drive for three seconds. After three seconds, shift back to the Neutral position leaving the shift lever in Neutral for three seconds. Perform this procedure 10 times (N-D-N-D-N-D...).
7. With the engine at idle, shift from Neutral to Reverse leaving the shift lever in Reverse for three seconds. After three seconds, shift back to the Neutral position leaving the shift lever in Neutral for three seconds. Perform this procedure 10 times (N-R-N-R-N-R...).

At the end of these maneuvers, the vehicle may still experience some minor driveability issues, but should learn improved shifting performance over the next several key cycles and driving time. Coach the customer about the transmission's ability to self correct shifting issues or concerns. The transmission adapts are always functional and operate at transmission oil temperatures above 40°C (104°F).

For vehicles repaired under warranty use: