Normal Operation

WARNING: This page is about a different car, the 2007 Lincoln MKX and 2007 Ford Edge. However, it is still accessible from the selected car via links, so may be relevant.

The steering wheel rotation sensor (which is integral to the steering angle sensor module) monitors the steering wheel position when the slotted-wheel in the sensor passes through the optical field of the sensor.

The steering angle sensor module sends steering wheel rotation (in degrees) to the ABS module along the high-speed controller area network (HS-CAN) bus. Fused ignition voltage is supplied to smart junction box (SJB) fuse 34 (5A) from battery junction box (BJB) fuse 53 (30A) along circuit CBB53 (GY/BN). SJB fuse 34 (5A) supplies this voltage to the sensor along circuit CBP34 (VT/BN). Ground for the sensor is provided along circuit GD115 (BK/GY).

If the ground or power to the steering wheel rotation sensor is interrupted, DTC C1278 will be set. Also, if the information sent to the ABS module over the HS-CAN bus is present but erratic, invalid (when compared to other inputs) or otherwise suspected to be incorrect, DTC C1278 will be set. If the information sent to the ABS module is missing completely, this indicates an issue with the HS-CAN bus and DTC U0126 will be set in the ABS module.

Possible Causes

Circuit open
Circuit shorted
Steering wheel rotation sensor