The Hill-start Assist Control (HAC) function helps the vehicle not to slip on a steep hill when starting up without depressing the brake pedal. When this function is operating, brake lamp turns on by the brake lamp relay for representing vehicle braking.
The HECU monitors the brake lamp relay (HAC relay) for normal operation. If there is an open or a short in the relay circuit, this DTC is set.
Item | Detecting Condition | Possible cause |
DTC Strategy |
•
Voltage Monitoring | 1. Open or short in the brake lamp relay(HAC relay) circuit 2. Faulty brake lamp relay(HAC relay) |
Enable Conditions |
•
When HAC brake lamp relay drive OFF - If the monitor of HAC Brake Lamp Drive is ON for 500ms, The failure is recognized - If the monitor of HAC Brake Lamp Relay is different from BLS signal for 3sec, The failure is recognized
•
When HAC brake lamp relay drive ON - If the monitor of HAC Brake Lamp Drive is OFF for 500ms, The failure is recognized - If the monitor of HAC Brake Lamp Relay is OFF for 500ms, The failure is recognized | |
Fail Safe |
•
Inhibit the HAC control and allow the ABS/EBD/ESP control. |
