What does it mean?
C1407 is a Chassis (ABS, traction control, steering) fault code. It indicates: Open or Short in Rear Speed Sensor RH Circuit .
Symptoms
- ABS, traction and stability lamps on, systems disabled
- Right rear wheel speed missing or erratic in live data while the front wheels read correctly
- ABS may activate briefly at low speed, or the rear may lock earlier than normal under hard braking
- Electronic parking brake or hill hold functions may be inhibited on some vehicles
- Trailer stability assistance unavailable where it is fitted
Likely causes
- Open or shorted right rear wheel speed sensor
- Sensor harness damaged along the underbody, where it runs near the fuel tank, exhaust and rear axle
- Corroded rear connector, often the worst affected corner for road salt and standing water
- Rusted or damaged tone ring on the right rear hub, common on older rear bearings
- Excessive rear wheel bearing play changing the air gap
- Harness pinched or stretched by rear suspension movement or a towbar installation
- Rodent damage to the rear section of the loom
How to fix it
- Road test and confirm which corner drops out by comparing all four wheel speeds
- Inspect the rear harness run for chafing, stretching and rodent damage, paying attention to the suspension flex points
- Open the rear connector and check for water, corrosion and green terminals; dry and reseal it
- Measure sensor resistance or output at the sensor connector and compare it with the opposite rear corner
- Test the circuit for open, short to ground and short to voltage from the module connector
- Remove the sensor, clean the bore, and inspect the tone ring and bearing for rust and play
- Replace the sensor or the rear hub assembly as the tests indicate, then verify all four speeds track together