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 CC(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.
The SCC ECU monitors SAS checksum and message counter, SAS signal, SAS status from the SAS through the CAN message. If the SCC detects improper signal or value, the SCC ECU sets DTC.
Item
Detecting Condition
Possible cause
DTC Strategy
CAN message monitoring
Improper alinement
Faulty SAS
Enable Conditions
Engine Run (engine rpm higher than 400 at least for 2s)
No low voltage/over voltage DTC
Threshold value
Abnormal checksum value
Abnormal message counter
Abnormal SAS signal received
Diagnosis Time
Continuous (minimum fault detect time : 500ms)
Recover Condition
As soon as the signal is alright again
Fail Safe
SCC Disengagement/Shutdown
Red SCC warning lamp turns on