PRE-RELEASE
Pressure sensor, tyre pressure (754)
| Pressure sensor, tyre pressure (754) |
| Main function |
The sensor transmits information on tyre pressure, temperature and direction of rotation to the control module, which in turn informs the driver is a tyre has low pressure.
| Type |
The tyre pressure sensor is an integrated sensor with transmitter, battery and valve. It comprises a plastic housing, with an electronic unit, which is joined to an aluminium housing with a valve. On the valve are a tapered seal and a crown nut, which is used to fit the valve into the corner of the wheel. The sensor weighs approximately 38 g.
| Engaging |
The sensor houses a 3V (500 mAh) lithium battery that is activated when speed exceeds 20 km/h. The battery is not replaceable.
| Function |
The pressure sensor measures tyre pressure, temperature and direction of rotation. The temperature value is only used in certain markets. Each sensor has a unique code which is transmitted with every information block. The sensors are fitted into special Saab rims. During normal operation, the sensor takes a reading every 10 seconds and transmits a signal once every minute. If the pressure has dropped by more than 0.08 bar from the latest reading, a new signal is transmitted after 10 seconds.
When battery voltage is low, the control module transmits a system fault message on the I-bus.
