What does it mean?
C1148 is a Chassis (ABS, traction control, steering) fault code. It indicates: ABS Hydraulic Valve Power Relay Circuit Short to Ground .
Symptoms
- ABS warning lamp is on and stays on, usually joined by the traction and stability control lamps
- ABS no longer works: no pedal pulsing under hard braking and the wheels can lock on wet or loose surfaces
- Normal braking is still there, but stopping distance grows and the car may pull under emergency braking
- Electronic brake force distribution and hill-start assist drop out, and the red brake lamp may light as well
- Repeated blown ABS fuse, or the relay buzzing or chattering at key-on instead of clicking once
Likely causes
- Wiring to the relay chafed through against a bracket, body seam or the edge of the hydraulic unit, touching bare metal
- Water or road salt inside the relay socket or the fuse box, bridging the control pin to ground
- Relay failed internally with its coil or contact winding shorted to the relay case
- Damaged or crushed harness section near the ABS hydraulic unit, often after suspension, subframe or accident repair work
- Rodent damage to the loom running along the inner wing to the fuse and relay box
- Failed low-side driver inside the ABS control module holding the circuit at ground permanently
- A repair splice or aftermarket accessory tapped into the ABS power circuit
How to fix it
- Note whether the ABS fuse has blown; a short to ground normally takes the fuse or makes the relay chatter
- Read all chassis codes together — if every valve and pump code appears at once, the shared power feed is the suspect, not the individual valves
- Pull the relay and check the socket terminals for water, corrosion and heat damage, then test the relay coil and contacts off the car
- With the relay out and the connector off the ABS module, measure resistance from the relay control pin to chassis ground; near zero ohms confirms the short
- Follow the harness from the fuse box to the hydraulic unit, opening the loom at every bracket, clip and flex point to find the chafe
- Repair the damaged section properly with soldered and sealed joints rather than a crimp under tape, then reseal the connectors
- If the wiring is clean and the short is inside the module, the ABS module must be repaired or replaced and coded to the vehicle