The DBC function is the shorten word of Downhill Brake Control function. When a vehicle goes down the hill, just pushing the DBC switch enables the car to keep its vehicle's speed at a constant value without operating the brake pedal. The DBC function is operated when the vehicle is on the decline and its velocity is under the predetermined speed.
The HECU monitors the brake lamp relay(DBC relay) for a normal operation and if there is a open or short circuit in the relay, this DTC is set.
Item
Detecting Condition
Possible cause
DTC Strategy
Voltage Monitoring
Open or short in the brake lamp relay(DBC relay) circuit
Faulty brake lamp relay(DBC relay)
Enable Conditions
When DBC brake lamp relay drive OFF
- If the monitor of DBC Brake Lamp Drive is ON for 500ms, The failure is recognized.
- If the monitor of DBC Brake Lamp Relay is different from BLS signal for 3sec, The failure is recognized.
When DBC brake lamp relay drive ON
- If the monitor of DBC Brake Lamp Drive is OFF for 500ms, The failure is recognized.
- If the monitor of DBC Brake Lamp Relay is OFF for 500ms, The failure is recognized.
Fail Safe
Inhibit the DBC control and allow the ABS/EBD/ESP control.
The DBC warning lamp is activated.