The tire pressure monitor (TPM) system alerts the driver when a large change in pressure of one tire exist, 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, instrument panel cluster (IPC) message center, and the driver information center (DIC) to perform the system functions. The EBCM contains the software to calculate relative tire pressure differences. The software requires up to 8 km (5 miles) of straight line, smooth road driving in each of the 4 speed ranges to complete the calibration process in order to have any capability for detecting a tire pressure condition. The speed ranges are as follows:

Each of the speed ranges have 2 modes of operation:

In calibration mode the TPM system is learning the tire pressure calibrations and can not detect a low tire pressure condition. In detection mode the TPM system has learned the tire pressure calibration and can detect a low tire pressure condition. The EBCM learns the tire pressure calibration for each speed range independently. Once the TPM system has learned the tire pressure calibration 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 one tire, so too will that tires circumference, radius, and diameter, 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 48-69 kPa (7-10 psi) lower or higher than the other three the EBCM commands the driver information center (DIC) message center to display. The CHECK TIRE PRESSURE warning message via a class 2 serial data circuit. The system does not alert the driver to which tire is high or low. The warning messages do not appear in either display if any of the following conditions are present:

To clear the CHECK TIRE PRESSURE warning message, refer to Tire Pressure Monitor Procedure .