What does it mean?
C1184 is a Chassis (ABS, traction control, steering) fault code. It indicates: ABS Hydraulic Valve Power Relay 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
- ABS lamp on together with the traction and stability control lamps, sometimes only after driving for a while
- ABS switched off, so there is no pedal pulsing or wheel speed regulation under hard braking
- Warning lamps can clear after a restart and come back on the next drive, especially on rough roads
- Braking is otherwise normal, so the change is only noticeable on wet, gravel or icy surfaces
- Missing or repeated ABS self-test noise from the hydraulic unit when the ignition is switched on
Likely causes
- Relay contact resistance rising with age, so the valve supply voltage sags under load
- Poor connection at the ABS module ground or at the body ground for the hydraulic unit
- Corroded high current fuse or a discoloured, heat softened fuse holder
- Water damaged ABS module connector with corroded feed and monitoring pins
- Wiring harness insulation cracked by underbonnet heat, giving an unstable connection under vibration
- Weak battery or a charging system that cannot hold voltage when the ABS pump and valves load the system
- Internal fault in the ABS module monitoring circuit that watches the valve supply
How to fix it
- Test the battery and charging system, then measure voltage drop on the main power and ground paths under load
- Look at the freeze frame voltage stored when the code set — a low value usually confirms a supply or ground problem
- Remove and inspect the valve relay and its socket, checking for pitted contacts, discoloured plastic and loose terminals
- Check the high current ABS fuses and their holders with a meter and by feel for heat damage
- Clean and retighten the ABS hydraulic unit ground stud and the body ground points in the same area
- Inspect the ABS module connector for corrosion, then wiggle test the harness with a meter connected to catch intermittent faults
- If supply, ground, fuse and relay are all good, the ABS control module needs repair or replacement, followed by coding and a system bleed if the unit is opened