TPMS Function

The TPMS monitors tire pressure using 4 valve stem mounted TPMS sensors, these sensors transmit tire pressure data to the BCM. The TPMS sensor locations and unique identifiers are trained (calibrated) to the BCM based on the training order. The BCM compares the tire pressure data sent by the sensors with a programmed desired tire pressure. This programmed pressure is the same pressure indicated on the VC label. If the tire pressure deviates from the programmed tire pressure the BCM, using the MS-CAN, signals the IPC to illuminate the TPMS warning indicator and to display a message in the message center. The programmed desired tire pressure cannot be changed.

For vehicles with different front and rear tire pressures, the tire pressures must be adjusted and the TPMS sensors must be trained following a tire rotation. Refer to: Tire Pressure Monitoring System (TPMS) Sensor Location Calibration . Failure to train the sensors results in a false low tire pressure event which causes the TPMS warning indicator to illuminate.

For vehicles with the same front and rear tire pressures, tire rotation does not affect the TPMS.

The diagnostic scan tool is a useful tool in diagnosing TPMS concerns and may be used to verify the accuracy of the tire pressure data transmitted by the TPMS sensors. This is accomplished by comparing the BCM tire pressure PID data to the actual tire pressure using a digital tire pressure gauge.