Test E: Speedometer/Odometer Is Inoperative

Pinpoint Test E: The Speedometer/Odometer Is Inoperative





Normal Operation
The instrument cluster receives the vehicle speed data from the powertrain control module (PCM) over the high speed controller area network (HS-CAN). The instrument cluster monitors the vehicle speed input from the PCM and commands the speedometer with a corresponding movement of the pointer.

The vehicle speed on the 5R55 transmission is generated by the PCM and calculated from the transmission output shaft speed (OSS) input and the tire size and axle ratio that is programmed at the end of the production line in the vehicle identification (VID) block.

The vehicle speed on the 6R60 transmission is generated by the PCM and calculated from the transmission OSS input sent from the transmission control module (TCM) over the HS-CAN bus and the tire size and axle ratio that is programmed at the end of the production line in the VID block. If the OSS signal to the PCM is missing or the OSS CAN message is missing, then the PCM will use an ABS vehicle speed sent by the ABS module to the PCM over the HS-CAN bus.

The odometer indicates the vehicle distance traveled whenever the ignition switch is in the RUN position, based upon rolling count data sent from the PCM over the HS-CAN. The instrument cluster provides a reset button to allow the trip odometer to be reset to 0. When the reset button is pressed, the trip odometer is reset. The trip odometer accumulates and registers up to 999.9 kilometers or 999.9 miles.

This pinpoint test is intended to diagnose the following:
- PCM
- instrument cluster