C0278 LEXUS, TOYOTA, SCION: OPEN OR SHORT CIRCUIT IN ABS SOLENOID RELAY CIRCUIT
POST UPDATED IN February, 2023
C0278 Code failures by brands
Description of DTC code C0278
The ABS solenoid relay provides the power required by the ABS solenoid and the TRAC solenoid. Once the ignition switch is turned on, the car’s speed reaches 6 km/h. To determine if the solenoid is OK, an initial self-diagnostic is made, then the relay switches on. In case there is a fault in its circuit, the relay switches off.
The DTC C0278 OBDII code setting occurs when the supply voltage to the solenoid relay (+ BS) drops below the DTC detection level because the battery or alternator outputs are not as required.
Symptoms of fault code C0278
- Check Engine light ON.
- The ABS warning light turns on.
Causes of OBD2 C0278
The OBD2 fault code C0278 is stored due to the following reasons:
- The ABS Solenoid circuit wiring or connections may be faulty.
- The Anti-Lock Brake System Solenoid relay or relay fuse may be bad.
- Possibly the ABS Actuator (Slip Control ECU) is in bad condition.
Possible solutions of the DTC code C0278
To troubleshoot the C0278 OBDII diagnostic code C0278, try this:
- Check the wires associated with the ABS Solenoid circuit and verify that they are not deficient due to wear or burn spots. If you find one of these conditions, make the appropriate adjustments.
- Check the integrity of the Anti-Lock Brake System Solenoid relay and its fuse. If you determine that one of these is bad, replace it.
