21-021-15

Flash: Transmission Diagnostic And Shift Enhancements This bulletin involves reprogramming the Transmission Control Module (TCM) with new software. A small number of customers may experience a Malfunction Indicator Lamp (MIL) illumination on vehicles equipped with a 948TE 9 speed automatic transmission (sales code DFH or DFJ). Upon further investigation, a technician may find Diagnostic Trouble Code (DTC) P1DAD - Input Shaft-Output Shaft Direction Correlation stored in the TCM memory. In addition to addressing the above DTC, this TCM calibration update is being released to enable the new wiTECH based ?Transmission Quick Learn? procedure to be performed anytime the transmission adaptation memory cells are cleared or when addressing customer concerns of poor shift quality. It is also being released to improve transmission downshift response time during normal driving.