Gear Selector Module (GSM)
The Gear Selector Module (GSM) is located on the left-hand side of the gear selector assembly. The Gear Selector Module (GSM) is powered by and communicates via serial communication with the Transmission Control Module (TCM). The gear position is indicated in the Driver Information Module (DIM) and on certain versions also by LEDs in the gear shift knob.
There is a directly connected cable from the Transmission Control Module (TCM) to the Gear Selector Module (GSM) which controls the shift-lock solenoid. The power supply and ground for the shift-lock solenoid are directly connected to the Gear Selector Module (GSM).
The Gear Selector Module (GSM) can be diagnosed. In the event of a fault a signal on fault status is sent to the Transmission Control Module (TCM) which then stores any diagnostic trouble codes (DTC).