AHLS provides driver with the best visibility by adjusting vertical direction of the headlamp. It consists of ECM, Linkage and actuator. The ECM detects the vehicle speed to use it as a compensation factor for the actuator control.
When a vehicle drives at a constant speed, the AHLS-ECM controls the actuator slowly with using vehicle's speed information. As the result of that, a driver doesn't feel its lamp's leveling operation.
When a vehicle stops, the AHLS-ECM controls the actuator relatively fast.
The ECM sets DTC C1212 if the speed signal line carries a higher frequency than defined maximum value( approx. 300Hz) for 2 seconds.
Item | Detecting Condition | Possible Cause |
DTC Strategy |
•
Frequency check |
•
Poor connection
•
Faulty Vehicle speed sensor
•
AHLS-ECM faulty |
Detecting mode |
•
When vehicle is driving | |
Threshold Value |
•
Frequency >300Hz | |
Detecting time |
•
2 Sec |
Fig.1) It shows Signal waveform at driving condition that changes frequncy according to vehicle speed.
