Flash: 845RE Transmission Shift Enhancements

Bulletin number

21-006-15 REV-B

Component

Power train

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. ? Harsh or erratic 8-6 downshift during freeway driving. ? Harsh or erratic 6-4 and/or 6-3 downshift during city driving. ? Harsh or erratic upshifts while in Sport Mode. ? Less than desired downshift timing (longer time to downshift than expected). ? Less than desired downshift feel during coasting decelerations and while passing. ? Less than desired shift feel when shifting from reverse to drive or drive to reverse while the vehicle is stationary (i.e. garage shift). ? Less than desired upshift feel during normal non-aggressive driving. ? Less than desired powertrain performance at higher altitudes. ? Less than desired paddle shifter operation.

Owners of these vehicles have filed 29 complaints in the transmission category.