TPMS Function

The TPMS system 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 Medium Speed Controller Area Network (MS-CAN), signals the IPC to illuminate the TPMS warning indicator and to also display a message on the message center. The programmed desired tire pressure cannot be changed.

The 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 Parameter Identification (PID) data to the actual tire pressure using a digital tire pressure gauge. Training the sensors is not necessary after a tire rotation on vehicles with the same front and rear tire pressures however, the BCM cannot recognize that the sensor identifiers have been moved to different positions and will retain the original position information for each sensor.