Transmission Range Indicator

The electronic gear selector indicator gives an indication to the vehicle operator of the transmission gear that has been selected with the automatic transmission gear selector lever. This indicator is controlled by the circuit board based upon programming and electronic messages received from the TCM, over the CAN data bus.

The gear selector indicator information is displayed by the odometer VFD unit soldered onto the electronic circuit board, and the VFD will not display the gear selector indicator information after the ignition switch is turned to the OFF position. Each time the is disconnected from battery current for more than about five minutes, it must configure itself for the automatic transmission type that is in the vehicle once it is reconnected to battery current. The circuitry operates the gear selector indicator to provide the following features:

• Selected Gear Message  - Each time the receives an electronic selected gear  message from the TCM, a box will be illuminated around the appropriate character in the gear selector indicator. The box will remain illuminated until the receives a different selected gear  message, or until the ignition switch is turned to the OFF position, whichever occurs first.
• Communication Error  - If the fails to receive a selected gear  message from the PCM within three seconds, the circuitry will display all gear selector positions boxed (selected) until a valid selected gear  message is received or until the ignition switch is turned to the OFF position, whichever occurs first.

The TCM continually monitors a hard-wired multiplex input from the Transmission Range Sensor (TRS), then sends the proper message to the IPC.