What does it mean?
C1175 is a Chassis (ABS, traction control, steering) fault code. It indicates: ABS Hydraulic Valve Power Relay Circuit Short to Ground .
Symptoms
- ABS, traction and stability control warning lamps on together from key-on
- ABS is inoperative, so the pedal no longer pulses and a wheel can lock during a panic stop
- Blown ABS fuse, sometimes repeatedly, or a rapid chattering noise from the relay box
- Stopping distances on wet, icy or gravel surfaces increase noticeably
- Hill-start assist, trailer aids and electronic brake force distribution stop working
Likely causes
- Moisture sitting in the underbonnet fuse and relay box after a blocked scuttle drain or a damaged box lid seal
- Relay control wire rubbed bare where the loom crosses a metal edge or is clipped to the hydraulic unit bracket
- Internal short inside the relay between the winding and its metal frame
- Harness pinched during a previous brake, subframe or engine mount repair and slowly cutting through
- Corroded and swollen terminals in the ABS module connector, letting adjacent pins touch the shell
- Salt and grit damage on the loom section that runs low behind the front wheel arch
- Shorted low-side driver inside the ABS control module
How to fix it
- Check the ABS fuses; a short to ground usually blows one, and the fuse that failed tells you which branch to follow
- Read the whole chassis code list — a block of valve and relay codes at once means one shared circuit, not several failed parts
- Open the fuse and relay box and look for water tracks, white powdery corrosion and green terminals before touching the wiring
- With the relay removed and the ABS module unplugged, measure resistance from the control terminal to chassis ground; a very low value proves the short
- Unwrap the loom from the fuse box to the hydraulic unit and inspect each clip, bracket and body pass-through for chafe
- Test the relay off the car for a winding to case short, and replace it if it fails
- Repair the harness with sealed joints and reroute it clear of sharp edges before clearing codes and road testing