Gear selector module (GSM)

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2006 Volvo S80, 2005 Volvo S80, 2004 Volvo S80, 2003 Volvo S80, and 2002 Volvo S80. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Gear Selector Module (GSM)

Courtesy of VOLVO CARS OF NORTH AMERICA.

The gear selector assembly is positioned in the center console and is mechanically connected to the transmission by a cable which moves the gear valve in the valve housing. The gear selector module (GSM) is positioned on the top panel of the gear selector assembly.

The gear selector module (GSM) receives gear position signals from the transmission control module (TCM) via serial communication. The transmission control module (TCM) receives the present gear position from the gear-shift position sensor. The LEDs in the top panel indicate the selected gear to the driver. The gear selector module (GSM) communicates serially with the central electronic module (CEM). The central electronic module (CEM) sends a signal to the gear selector module (GSM) to activate the shift-lock. The power supply and ground for the shift-lock solenoid are directly connected to the gear selector module (GSM).

The "W" switch in the gear selector assembly top panel is positioned on the printed circuit board for the gear selector module (GSM) and activates Winter mode. The gear selector module (GSM) checks the back-up (reverse) inhibitor function based on the vehicle speed signal from the transmission control module (TCM).

There are diagnostics for the gear selector module (GSM). Diagnostic trouble codes (DTCs) are stored in the transmission control module (TCM) in the event of a fault.