The Steering angle sensor(SAS) is installed in MDPS assembly.
The SAS is used to determine turning direction and speed of the steering wheel.
The HECU uses the signals from the SAS when performing ESP-related calculations.
If the SAS signal is different from calculated value by yaw-rate sensor and wheel speed sensor, mechanically impossible SAS signal is detected, there is a difference between SAS signal and driving condition of the vehicle calculated from yaw-rate sensor and lateral G sensor, a failure is detected.
Item
Detecting Condition
Possible cause
DTC Strategy
Signal Monitoring
Short of steering angle sensor circuit
Faulty steering angle sensor
Case 1
MonitoringPeriod
Continueosly on driving
Enable
Conditions
In case of straight and stable driving over 30kph, monitoring a fault if it is more than 25deg to difference between previous SAS offset and mean of estimated SAS offset
Case 2
Continous (no low- voltage and no errors after IGN on)
Monitoring a fault if sensor values keep out of the physical range of steer for 600ms
Case 3
Continuous (no low-voltage, no errors and more than 2.75kph speed after IGN on)
Monitoring a fault if ?Sensor values keep more than 40deg for 40ms.
Case 4
Continuous (during driving)
In case of stable driving, monitoring a fault if it is more than 10deg to the difference between measured SAS offset and estimated SAS offset
Case 5
In case of over 70kph driving, monitoring a fault if conditions between estimated SAS vaules and measured SAS sensor value are not proper to driving status.
Fail Safe
Inhibit the ESP control and allow the ABS/EBD control.
The ESP warning lamps are activated.