Park Reverse Neutral Drive Low (PRNDL) Display - Automatic Transmission

The IPC displays the selected gear position as determined by the TCM. The gear position is communicated via GMLAN from the TCM through the BCM to the IPC. The IPC receives a GMLAN message from the BCM indicating the gear position. If the BCM detects a malfunction in the transmission range switch where vehicle speed is continually greater than the indicated gear position's capability, the PRNDL display on the DIC will display the letter P. The PRNDL display on the DIC can also blank if:

• The BCM detects a malfunction in the transmission range switch circuit in the mid range.
• The IPC detects a loss of GMLAN communications with the BCM.
• There is a loss of communication with the TCM.