Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Gear Selector Module (GSM)
The gear selector assembly is located in the tunnel console and is mechanically connected to the transmission via a cable that moves the shift valve in the transmission control system. The gear selector module (GSM) is located on the left side of the gear selector assembly. The control module is powered by and communicates via serial communication with the transmission control module (TCM). The gear position is indicated by a number of LEDs in the top panel of the gear selector assembly.
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).
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.