PRE-RELEASE
Yaw rate sensor (658)
| Yaw rate sensor (658) |
The yaw rate sensor comprises a combined micromechanical yaw rate sensor and lateral acceleration sensor. It is located on a bracket on the exhaust pipe tunnel ahead of the gear lever. This location has been chosen as the sensor should be positioned as close as possible to the car's centre of gravity and centre line (X-axis).
Its housing is hermetically sealed and filled with nitrogen to protect the components from being affected by the environment. The sensor is used to measure the physical forces of the yaw rate and the lateral acceleration of the vehicle.
| Pin | Function | In/Out | Test reading |
|
1
|
Reference signal
|
Out
|
»
2.6 V
|
|
2
|
Reference signal from ESP control module
|
In
|
»
3.2 V, 50 Hz square wave, pulse ratio 50%
|
|
4
|
Angle of rotation
|
Out
|
-138°/s - +138°/s
|
|
5
|
Lateral acceleration
|
Out
|
0 - 5 V
2.6 V when driving straight ahead. |
|
6
|
System ground
|
Ground
|
| Yaw rate sensor |
The sensor contains a number of thin plates that have weights and are freely suspended independent of each other. The weights, and thereby the plates, move around their own vertical axis in relation to the movement of the vehicle. When the distance between the plates changes, an electrical signal is generated by the gyro sensor. This signal provides the control module with information about the car's rotation.
| Lateral acceleration sensor |
The acceleration sensor comprises three capacitor plates. One of these capacitor plates is freely suspended between the two fixed plates. The forces of acceleration that arise when the car moves sideways cause the swinging plate to move. This changes the capacitance and produces an electrical signal. This signal provides the control module with information about the car's lateral movement.
| Diagnostic help |
Yaw rate sensor
The yaw rate sensor value can be read using the diagnostic tool. The reading should be 0°/s when the car is stationary. A DTC is generated if a faulty or improbable signal is produced by the lateral acceleration sensor, or if there is an open circuit, short to ground or short to a positive cable.The ESP, TCS and ESP OFF lamps will not come on.
