Description And Operation
Description
The vehicle can be equipped with the Tire Pressure Monitoring (TPM) system. The system can constantly monitor all four pressure values of the tires through sensors fitted on the valve stems, and can warn the driver, through the instrument panel, if tire pressure decreases or if there is a problem in the operation of the system itself.
The TPM is provided as standard on all models and shows the tire pressure values through a dedicated submenu in the instrument panel display. Once the pressure value of a tire is influenced by deflation, the relative pressure value will flash in the instrument panel through the EVIC, which can be 3.5" or 7" (also called DID). The system also resets automatically after the wheels have been rotated, thus guaranteeing correct information about tire pressure and displaying it at all times in the EVIC. When tire pressure is 48-55 kPa (7-8 psi) below the specification listed on the label, the system emits an acoustic signal, illuminates the ISO low tire pressure warning light, and displays the pressure of the four active tires in the EVIC display.
If a system fault is detected, the warning light will flash for 75 seconds, then remain on continuously. Dashes will take the place of the pressure reading if a sensor is not correctly operating. A five-sensor system is available for vehicles with a full-size spare wheel (in markets where provided).
Tire Pressure Sensor
The TPM system use four or five tire pressure sensors designed for mounting in place of a traditional tire valve. The tire pressure sensor includes a stem that looks similar to a standard stem. The sensor body, located at the bottom of the stem contains a sensor, a processor, a transmitter/receiver, and a battery that lasts up to ten years. If the battery fails, the sensor must be replaced.
The sensors wireless and transmit tire pressure information at a frequency of 433 MHz. The tire pressure sensors send a tire pressure sensor value every 30 seconds when the vehicle is in motion and approximately every 13 hours when the vehicle is not in motion. The sensors also transmit a unique ID code to differentiate the sensors from those on nearby vehicles.
Operation
TPM thresholds have been established for the original tire size equipped on the vehicle. Use original size tires only to maintain system accuracy.
The Radio Frequency Hub (RFH) module receives the radio signals from the tire pressure sensors and sends the relevant values to the other modules via CAN-C. The RFH module identifies the sensor position, receives the sensor data, compares the pressure data with the standard pressure values stored in the non-volatile memory, determines whether there is a problem in the tire pressure and stores the warnings regarding tire pressure and system faults.
The RFH uses the tire rotational direction and the signal strength to determine the location of each tire pressure sensor. When the vehicles is travelling forwards, tires on the right side of the vehicle rotate clockwise and tires on the left side rotate counter clockwise. Since the RFH is located above the headliner in the rear of the vehicle, rear sensors will have a stronger radio signal than front sensors.
When a sensor is installed in a tire on the vehicle, the RFH can automatically identify the sensor and its location during the first ensuing drive cycle. Identification will take approximately 10 minutes but the speed of the vehicle must exceed 24 km/h (15 mph). The TPM-RKE 9936 analyzer can also be used to program the new sensor identification number in the RFH.
For the removal and installation of the RFH, refer to MODULE, RADIO FREQUENCY (RF HUB), REMOVAL AND INSTALLATION .
The sensor IDs can also be programmed using a Scan Tool. Scan each TPM sensor at each road wheel, and store each Sensor ID in the correct location:
- Left Front
- Right Front
- Right Rear
- Left Rear
Connect the Scan Tool. Then follow the programming steps outlined in the Scan Tool.