What does it mean?
C1228 is a Chassis (ABS, traction control, steering) fault code. It indicates: ABS Hydraulic Valve Power Relay Circuit Short to Battery . This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms
- ABS and stability lamps on and staying on
- Valve relay stays pulled in after the key is switched off, sometimes with a slight hum from the hydraulic unit
- Battery going flat when the vehicle stands for a day or two
- ABS and traction functions disabled
- Blown ABS fuses on some vehicles, sometimes repeatedly
Likely causes
- Control wire rubbed through onto a permanently live feed in the engine bay fuse box area
- Water or salt inside the relay box connecting the control pin to a live pin
- Relay contacts welded closed after repeated heavy current, feeding voltage back into the circuit
- Incorrect relay fitted, with different internal wiring or a missing suppression diode
- Retrofitted electrical accessory connected into the ABS supply harness
- High side driver inside the ABS module failed short
How to fix it
- Disconnect the ABS module and check for voltage on the relay control terminal with the key both off and on
- Trace the harness beside the fuse box and any heavy live cables looking for chafe marks and melted insulation
- Open and dry the relay box, then clean corrosion and water tracks from the pins
- Remove the relay and check for welded or stuck contacts, and confirm the correct part is fitted
- Disconnect aftermarket accessory wiring in the area and retest the circuit
- Repair the damaged harness and secure it away from live cables
- Verify the parasitic drain has gone before returning the vehicle, and treat the module as the last suspect