What does it mean?
C1158 is a Chassis (ABS, traction control, steering) fault code. It indicates: ABS Hydraulic Valve Power Relay Circuit Failure .
Symptoms
- ABS warning lamp on, usually together with the traction and stability control lamps
- ABS is off: no pedal pulsing under hard braking and the wheels can lock on wet or loose surfaces
- Ordinary hydraulic braking still works, but stopping distances get longer and the car may pull under panic braking
- Electronic brake force distribution and hill-start assist drop out and the red brake lamp may light
- The single self-test click from the ABS unit at key-on is missing, or repeats several times
Likely causes
- Failed valve power relay with burnt contacts or an open coil winding
- Blown or intermittent high current fuse on the valve power feed
- Corroded, heat damaged or spread terminals in the fuse and relay box that supplies the ABS hydraulic unit
- Water ingress into the ABS module connector, leaving corrosion on the power and feedback pins
- Chafed, brittle or badly repaired wiring between the fuse box, the relay and the hydraulic unit
- Weak battery, dirty battery posts or a poor chassis ground dropping voltage as the relay pulls in
- Internal failure of the driver stage inside the ABS control module that switches the relay
How to fix it
- Check battery voltage and clean the battery and chassis ground connections first; this code is a classic low voltage side effect
- Read all stored chassis codes together — if every valve and pump code is present, suspect the shared power feed rather than the components
- Pull the ABS valve relay, inspect the contacts and socket for heat damage, then measure the coil and contact resistance off the car
- Test the ABS fuses, including the high current ones, with a meter rather than judging them by eye
- Unplug the ABS module connector and inspect both halves for water, corrosion and pushed back terminals
- Reconnect and measure voltage at the valve supply while the module runs its self-test, wiggling the harness to catch intermittent drops
- If feed, ground and relay all check out, the fault is inside the ABS control module and it needs repair or replacement with correct coding