Component Description: GSM
When the driver needs to change gear position the driver selects P R N D or S by pressing a GSM button. The GSM reads the switch inputs and sends a request over the High Speed Controller Area Network 2 (HS2-CAN) through the GWM over the High Speed Controller Area Network 1 (HS1-CAN) to the PCM. The PCM receives the input from the GSM, combines in vehicle conditions to determine commanded transmission range then sends a command to the TRCM through a GWM over the High Speed Controller Area Network 2 (HS2-CAN). The TRCM will act on the command from the PCM by moving the transmission to the commanded position via a selector lever shift cable. The PCM reads the transmission range sensor (TRS) and confirms the correct position has been achieved. The PCM then sends a message to the GSM and the IPC to display the current transmission range.
Each GSM button has three individual switch contacts that are used as input that the button has been pressed. If one switch contact is seen as nonfunctional the system will still work properly. However, if two switch contacts fail the button is no longer deemed reliable and a fault message is displayed. When park is selected above 5 mph neutral is provided along with a message in the IPC. The Brake Transmission Shift Interlock (BTSI) CAN signal is used for normal function to shift from P.