What does it mean?
C1179 is a Chassis (ABS, traction control, steering) fault code. It indicates: ABS Delta Stroke Sensor .
Symptoms
- Brake and ABS warning lamps on, often with a stability control lamp and a warning message
- Brake pedal feel changes: it can go long and soft or unusually hard, depending on the system design
- ABS and stability control functions are switched off
- On hybrid and electrified vehicles, regenerative braking is reduced and the transition to friction braking feels abrupt
- Warning buzzer or repeated brake system alerts each time the car is started
Likely causes
- Internal failure or drift of the stroke sensor element
- Corroded, wet or loose sensor connector in the area behind the master cylinder and brake booster
- Chafed or broken wiring between the sensor and the brake actuator or ABS module
- Sensor zero point never learned after brake actuator, master cylinder, sensor or module replacement
- Air in the hydraulic circuit or a low fluid level, so the measured stroke no longer matches the expected value
- Internal leak or wear in the master cylinder or brake actuator assembly changing the stroke characteristic
- Low system voltage or a poor ground affecting the sensor reference
How to fix it
- Check brake fluid level and condition first, and look for leaks at the master cylinder, actuator and calipers
- Read all brake system codes and the freeze frame; low voltage or another actuator code will often explain this one
- Watch the live stroke sensor value with the pedal released and slowly applied; it should start near its stored zero and rise smoothly
- Inspect the sensor connector and wiring behind the booster for moisture, corrosion, chafe and pins that have backed out
- Measure supply voltage, ground and signal at the sensor with the ignition on, following the manufacturer test values
- Bleed the system correctly, including the actuator bleed routine where required, then run the sensor zero point learning procedure
- Replace the stroke sensor or the actuator assembly only after the fluid, wiring and calibration checks are complete, and repeat the learning procedure afterwards