What does it mean?
C1142 is a Chassis (ABS, traction control, steering) fault code. It indicates: ABS Pressure Sensor Circuit .
Symptoms
- ABS, stability control and often the red brake warning lamp on
- Brake assist, hill hold and stability functions unavailable
- Live data shows brake pressure well above zero with the pedal released
- Pedal feel changes or the pedal feels inconsistent between stops
- Stability control intervenes unexpectedly during light braking
- Fault sets during braking rather than at key on
Likely causes
- Internal sensor failure, so the reported pressure drifts or sticks at one value
- Corroded or wet connector at the sensor, which usually sits on the hydraulic unit or master cylinder
- Chafed, broken or shorted sensor wiring in the engine bay
- Fault on the sensor reference or ground circuit shared with other chassis sensors
- Air in the brake hydraulics making the measured pressure implausible during braking
- Sensor loose in its port or fitted with a damaged seal
- Failed input circuit inside the ABS control module
How to fix it
- With the pedal released and the engine off, read the pressure value, it should be close to zero
- Press the pedal and watch the value rise smoothly and fall back again
- Inspect the sensor connector for moisture and corrosion and check terminal tension
- Measure the reference voltage and ground at the sensor connector
- Check the wiring for continuity and for shorts to ground and to battery voltage
- Bleed the brakes if the pedal is spongy and the pressure signal looks unstable
- Replace the sensor if it is a separate part, or the hydraulic unit if the sensor is integral, then code and bleed