SCC(Smart Cruise Control) is a system added additional function that can keep distance from the car ahead safely according to speed of the car ahead by using radar sensor to existing conventional ACC(Auto Cruise Control) function. SCC recognizes the closest one among the cars ahead on front line as control target when vehicle goes straight . But in case of the vehicle being in a curved lane, SCC recognizes the closest one within same lane among the cars ahead as control target although that is not on the front line. It is essential for SCC to recognize a turning radius to determine a control target. WSS(wheel speed sensor), YAW rate sensor, SAS(steering angle sensor) signals are used by reference data. SCC can predict driving condition based on these signals and can determine proper control target according to driving condition.
SCC monitors SAS checksum, message counter, SAS signal, SAS status with every reception of the CAN message. SCC sets this code when SCC detects improper signal or SCC detects SAS offset value higher than threshold after driving more than 500km.
Item
Detecting Condition
Possible cause
DTC Strategy
CAN message monitoring
Improper alinement
Faulty SAS
Case1
Enable
Conditions
After vehicle is moved over a distance of at minimun 500km.
Threshold value
SAS offset value > 12 °
Case2
Engine Run (engine rpm higher than 400 at least for 2s)
No undervoltage detected
Thresholdvalue
Abnormal checksum value
Abnormal message counter
Case3
Abnormal SAS signal received
Internal state of steering angle sensor is not OK
Diagnosis Time
Immediately
Recover Condition
As soon as the signal is alright again
Fail Safe
Red SCC warning lamp turns on