Design

Design

Tire pressure monitoring system (TPMS)




The purpose of the tire pressure monitoring system, TPMS, is to enable the driver to have optimum tire pressure by giving a warning when the pressure in any of the tires becomes too low. Correct tire pressure is important for:
- achieving good fuel economy
- achieving optimum comfort and good driving characteristics
- preventing flat tires due to too low tire pressure.
The function is integrated in the central electronic module (CEM). Sensors are installed together with the air valve on each wheel to measure the air pressure in the tires.

Note! The system must be regarded as a driver aid to maintain the correct tire pressure. The system must NOT be regarded as a warning system that indicates that there is a serious problem with the vehicle. No tire is completely sealed - there is always slight leakage as the tire can never be completely sealed to the rim. When inflating the tire with air, you must, as much as possible, ensure that the tires are at same temperature as the outside temperature. Furthermore, "Comfort pressure" should not be applied as this gives a tire pressure that is too close to the parameter for the monitoring system, which means that even small changes in temperature or load can cause the pressure in the tires to be too low for the system to consider acceptable. When inflating with air, the tires must be filled to the pressure stated on the decal located on the car body. The pressure is calculated with regard to fuel economy, comfort and safety. Therefore, these pressures MUST be followed. If the decal is missing or damaged, a new one must be ordered and applied. This is especially important on vehicles with TPMS.

Tire pressure sensor




The tire pressure sensors are installed together with the air valve on the rim. The sensor consists of a pressure sensor, a communication circuit, an acceleration sensor and a battery.

Note! Special procedures are required for removing the tire from the rim depending on vehicle model and tire type. This is to prevent damaging the sensor. See the specific mechanical information instruction under Repairing/Removal, replacement and installation.