What does it mean?
C1208 is a Chassis (ABS, traction control, steering) fault code. It indicates: Wheel Speed Sensor Rear-LH Invalid/No Signal .
Symptoms
- ABS, traction and stability control lamps all on
- Rear left wheel speed stays at zero on the scan tool while the vehicle is driven
- ABS never activates, so the rear can lock and the car can feel unstable during heavy braking
- Stability control is unable to brake that wheel individually, so the car understeers or slides further before recovering
- Hill-hold, electronic parking brake or trailer functions may report their own faults
Likely causes
- Tone ring badly rusted or with broken teeth, which is common on rear hubs exposed to salt
- Sensor tip caked with brake dust and ferrous particles
- Corrosion in the sensor bore lifting the sensor so the air gap is too large to read the ring
- Sensor dead internally, with normal circuit resistance but no output
- Damaged sensor lead reducing the signal below the level the module will accept
- Rear wheel bearing worn so that the ring runs away from the sensor face
- Incorrect hub, bearing or sensor fitted, with a tooth count that does not match the module's calibration
How to fix it
- Drive slowly with live data displayed and confirm which channel reads zero while its circuit resistance is normal
- Remove the sensor, clean the tip and the bore back to clean metal and check for rust building up behind the sensor
- Rotate the wheel by hand and inspect the tone ring around its whole circumference for rust flaking, cracks and lost teeth
- Refit the sensor fully home and confirm the air gap is to specification
- Test the sensor itself: winding resistance on a passive type, supply voltage and switched output on an active type
- Check rear bearing play and confirm the correct hub and sensor combination has been fitted, especially if the corner has been repaired before
- Replace the sensor if it gives no output, or the hub and bearing assembly if the tone ring is damaged, then verify all four channels agree