What does it mean?
C1254 is a Chassis (ABS, traction control, steering) fault code. It indicates: Brake Booster Pump Motor Relay Contact Circuit Failure . 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
- Red brake warning lamp together with ABS and stability lamps
- Hard, high brake pedal with little or no power assist
- Pump motor does not run at all, or runs erratically and cuts out
- Noticeably longer stopping distance and a wooden pedal feel
- ABS and traction/stability control switched off
- Audible warning or a brake system message in the cluster
Likely causes
- Burnt, pitted or welded contacts inside the brake booster pump motor relay
- Corroded or loose terminals in the relay socket that feeds the pump motor
- Blown high-current fuse or fusible link in the pump motor supply leg
- Chafed, open or high-resistance wiring between the relay contacts and the booster pump motor
- A pump motor drawing excessive current and burning the contacts
- Weak battery or corroded battery cables leaving low voltage on the contact circuit
- Faulty ABS/brake control module monitoring the contact feedback (least likely)
How to fix it
- Read all stored codes and the freeze frame data, and note whether the fault is current or historic
- Inspect the fuse, the relay and its socket in the underhood box for melted plastic, discoloured terminals and corrosion
- Fit a known good identical relay and see whether the fault clears
- Measure voltage drop across the relay contacts while the pump is commanded on; more than a few tenths of a volt means bad contacts
- Check for battery voltage at the pump motor connector during a commanded run, and check the ground side as well
- Measure the pump motor current draw; excessive draw points to a failing motor rather than the relay
- Repair the damaged harness or replace the relay, and only then consider the booster/pump assembly