Tire Pressure Monitoring (TPM) - Operation

OPERATION

TIRE PRESSURE MONITORING

The Tire Pressure Monitoring (TPM) system is designed to operate without loss of function for all OEM tire construction for this vehicle. Sensors, mounted to each road wheel as part of the valve stem, transmit an RF signal indicating their individual pressure to a receiver located in the TPM module. These transmissions occur approximately once every minute at speeds over 15 mph (24 km/h). For more information on sensors, Tire Pressure Monitoring (TPM) Sensor - Operation.

If the TPM module detects that the tire pressure in any road tire is going low, beyond the Low Pressure (lamp) ON threshold (see placard table below), a chime will sound and the indicator lamp will turn on. In addition to the chime and lamp, a graphic display of the pressure value(s) and position of the low tire(s) will flash in the Electronic Vehicle Information Center (EVIC). Once pressure in the suspect tire(s) raises above the Low Pressure (lamp) OFF Threshold (see placard table below), and the TPM module receives a valid transmission from the sensor, the lamp will go out. If a system fault is detected due to a missing sensor signal, in addition to a chime and a indicator lamp flashing, a "Check TPM System" text message will be displayed in the instrument cluster, and the tire pressure graphic display will have "- -" in place of the pressure value. After the flash sequence, the TPM indicator lamp will remain illuminated. The system will return to normal once the TPM module receives a valid transmission from that sensor location. If a system fault is detected, the indicator lamp will flash on/off for 75 seconds and then remain on solid.

If the TPM module detects a warning or fault condition at ignition key ON it will wait approximately ten seconds before sending the first request to illuminate the indicator lamp. This will assure that the display module has concluded its bulb check period. The display module will request a chime once per ignition cycle when a "warning" or "fault" condition is detected. A "warning" or "fault" condition will remain enabled until the problem causing the condition is corrected and reset.

The TPM module shall continuously monitor for the receipt of tire pressure RF message transmissions from the wheel sensors during the ignition key ON cycle. The wheel sensor IDs and the location of each sensor (e.g. Tire 1, Tire 2 etc.) are learned by the TPM control module using signal strength and direction of wheel rotation as received by the TPM module from each of the sensors, and updates the graphic display when necessary or during a service procedure, as required.

The TPM System will continue to warn the driver of low tire pressure as long as the condition exists, and will not turn off the indicator lamp until the tire pressure is at or above the Low Pressure (lamp) OFF threshold (see placard table below). The system will automatically update and the TPM indicator lamp will turn off once the updated tire pressures have been received.

Tire pressure will vary with temperature by about 1 psi (6.9 kPa) for every 12°F (6.5°C). This means that when the outside temperature decreases, the tire pressure will decrease. Tire pressure should always be set based on cold inflation tire pressure (placard pressure). This is defined as the tire pressure after a vehicle has not been driven for more than 3 hours (and in outside ambient temperature). The tire pressure will also increase as the vehicle is driven; this is normal and there should be no adjustment for this increased pressure. For a system fault, the system will return to normal once the TPM module receives a valid transmission from that sensor location.

TPM THRESHOLD PRESSURES

NOTE: To determine the pressure thresholds for a vehicle, refer to the Tire Inflation Pressure (Placard) Label found on the Driver B-pillar, then apply the placard pressure to the following table.