The Tire Pressure Monitor (TPM) system alerts the driver when a large change in the pressure of one tire exists while the vehicle is being driven. The TPM system uses the Electronic Brake Control Module (EBCM), ABS wheel speed sensor inputs, class 2 serial data circuit, and the Instrument Panel Cluster (IPC) message center to perform the system functions. The EBCM contains the software to calculate relative tire pressure differences. The software requires approximately 30 minutes of straight line driving in each of the three different speed ranges to complete the calibration process in order to have full capability of detecting a tire pressure condition. The speed ranges are as follows:

Each speed range has 2 modes of tire pressure detection:

The EBCM learns the tire pressure calibration for each speed range independently. In Monitor Mode 1, the EBCM has only partially learned the tire pressure calibration for the speed range and has limited detection capability for a tire pressure conditions. In Monitor Mode 2, the EBCM has fully learned the tire pressure calibration for the speed range and has full detection capability for a tire pressure condition. Once the TPM system is calibrated the EBCM monitors the ABS wheel speed sensor inputs, which will all be the same as the learned calibration if the tire pressures stay the same. If the pressure increases or decreases in a tire, so too will that tires circumference and radius, which causes that wheel speed sensor input to change. The EBCM recognizes this change in wheel speed as a tire pressure condition. If the pressure in one tire becomes at least 69 kPa (10 psi) higher or lower than the other three the EBCM commands the IPC message center to display the LOW TIRE PRESSURE warning message via a class 2 serial data circuit. This warning message is a re-configurable telltale and is ranked as lowest priority and may not be displayed if a higher priority message is requested at the same time. This message does not appear if more than one tire has high or low pressure, or if the system is not calibrated properly. The TPM system does not alert the driver to which tire is high or low. To turn off the LOW TIRE PRESSURE warning message, refer to Tire Pressure Monitor Procedure .