Flash: 845RE Transmission Shift Enhancements This bulletin involves reprogramming the Transmission Control...

Bulletin number

21-036-16

Component

Power train: automatic transmission: control module (TCM/PCM/tecm)

Summary

Flash: 845RE Transmission Shift Enhancements This bulletin involves reprogramming the Transmission Control Module (TCM) with the latest available software. A small number of customers may experience one or more of the following Symptom/Condition(s) and/or a Malfunction Indicator Lamp (MIL) due to an erroneous Diagnostic Trouble Code (DTC): P1DCD - TCM monitoring processor performance multiple clutches locked up. P1B13 - Park-By-Wire unintended out of park position. P0734 - Gear 4 Shift Incorrect Ratio set in the TCM memory.In addition, customers may experience the following conditions: Bump sensation felt during engine start/stop transition on light throttle acceleration (Stop-Start Multiple VSM System Sales Code XBU equipped vehicles only). Less than desired overall downshifts during normal driving. Less than desired downshifts during passing maneuvers. Less than desired upshift quality in lower gears.The following improvements are included in this update: Engine start/stop calibration update to allow Park and Neutral to be considered valid stop positions (Stop-Start Multiple VSM System Sales Code XBU equipped vehicles only).

Owners of these vehicles have filed 227 complaints in the transmission category.