Pinpoint Test AE: DTC C1278 - Steering Wheel Angle 1 And 2 Signal Faulted

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.

AE1 REPEAT THE ON-DEMAND SELF-TEST
- Key in ON position.
- Enter the following diagnostic mode on the diagnostic tool: HCM Self-Test
- Clear the DTCs and repeat the HCM on-demand self-test.
- Is DTC C1278 retrieved again?
1. YES : Go to AE2.
2. NO : The vehicle is operating correctly at this time. The HCM may have temporarily received incorrect data from the steering wheel angle sensor module.
AE2 CHECK THE ABS MODULE FOR DTC C1278
- Carry out the on-demand self-test for the ABS module.
- Is DTC C1278 retrieved?
1. YES : Go to AE3.
2. NO : Go to AE4.
AE3 CHECK FOR CORRECT SASM OPERATION
- Disconnect the SASM connector.
- Check for:
  - corrosion
  - damaged pins
  - pushed-out pins
- Connect the SASM connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
1. YES : INSTALL a new SASM. REFER to Steering Wheel Rotation Sensor in VEHICLE DYNAMIC SYSTEMS . TEST the system for normal operation.
2. NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
AE4 CHECK FOR CORRECT HCM OPERATION
- Disconnect the HCM connector.
- Check for:
  - corrosion
  - damaged pins
  - pushed-out pins
- Connect the HCM connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
1. YES : INSTALL a new HCM. REFER to Headlamp Control Module (HCM) in this. TEST the system for normal operation.
2. NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.