The Steering wheel angle sensor uses two sensors ( A-sensor and B-sensor ) to determine the direction of the rotation.
The main components of each sensor are LED, photo transistor and slit plate.
The slit plate, which has 45 holes, is installed between LED and photo transistor, and generates signals if slit plate rotates according to the steering wheel rotation.
The sensor signals are generated by photo transistor which is driven whenever the light passes through the holes. The HECU detects operating speed and direction of the steering wheel by this input signal, and the signal is used to input signal for anti-roll control.
If some signal voltage stays in abnormal voltage range, the time is counted seperately.
And if the monitored time exceeds the specified min. fault duration, failure is detected.
The monitoring starts 1sec after Power Up.
Item
Detecting Condition
Possible cause
DTC Strategy
Voltage Monitoring
Open or short of steering wheel sensor circuit
Faulty steering wheel sensor
Enable Conditions
When Vsas >4.2±0.1V or Vsas<1.2±0.1V or 2.1±0.1V<Vsas<2.9±0.1V continue 1sec.
- The monitoring starts 1sec after Power Up.
? Vsas : Voltage of the steering angle sensor.
Fail Safe
Inhibit the ESP/DBC control and allow the ABS/EBD control.
The ESP/DBC warning lamp is activated.