Theory Of Operation

The purpose of this diagnostic is to make sure that the input and output of the Transmission Control Module (TCM) shift by wire software corresponds. The input to the TCM shift by wire software is the driver request, vehicle and transmission conditions.

The following conditions are monitored by this diagnostic:

• A change in transmission position has occurred that was not requested.
• A requested change in transmission position from R/N/D has not occurred.
• The shift by wire stored values in Random Access Memory (RAM) have been corrupted.
• The transmission position transmitted between the shift by wire and the shift control software has been corrupted.
• The engaged transmission position is not displayed to the driver.