21-003-26

Flash: Transmission Control Module (TCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle may exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs):
• P0826-00 - Up/Down Shift Switch.
• P0827-00 - Up/down Shift Switch Circuit Low.
• P085F-00 - Up And Down Shift Switch Circuit Range/performance. Customers may also experience one or more of the following:
• **Customer is unable to switch the ignition to OFF when in Park gear.
• After shifting into Park, the Instrument Panel Cluster (IPC) will display that the transmission is in Neutral.** NOTE: **The transmission will actually be in Park and able to hold the vehicle, but the cluster display would indicate Neutral, preventing the engine from shutting off.**
• Rough/bumpy 2-3 power on upshifts and/or 3-2 coast down shifts.
• Vehicle enters into limp home mode. Other software improvements:
• Decreased sensitivity to DTCs P1D8A and P1D8B. This bulletin involves reprogramming the TCM with the latest available software.