What does it mean?
C1245 is a Chassis (ABS, traction control, steering) fault code. It indicates: Acceleration Sensor Output Malfunction .
Symptoms
- Stability, traction and ABS warning lamps on
- Stability control switched off, and hill-hold assist inactive
- Acceleration reading on the scan tool implausible, jumping or offset with the vehicle level and stationary
- Stability control intervening incorrectly on rough roads
- Fault often intermittent and worse over broken surfaces
Likely causes
- Sensor drifted or producing a noisy, unstable output
- Sensor bracket loose or bent, so vibration reaches the sensing element
- Wrong sensor orientation after refitting, giving a permanent offset
- Open, shorted or high resistance signal, supply or ground wire
- Corroded connector or water in the sensor mounting area
- Calibration not carried out after fitting the sensor or after suspension and alignment work
- Module input circuit failure
How to fix it
- Read the acceleration value with the vehicle level and stationary and check it sits near zero
- Take the vehicle on a gentle road test and confirm the value responds smoothly to braking and acceleration
- Check supply, ground and signal at the sensor connector, and look for corrosion and moisture
- Confirm the sensor is tight, correctly oriented and mounted on an undamaged bracket
- Wiggle test the harness while watching the live value to find an intermittent connection
- Perform the calibration routine and repeat the road test
- Replace the sensor if the output stays out of range, and calibrate it afterwards