C1277

Symptoms

• ABS or traction control warning light illuminated
• malfunction indicator lamp on
• loss of traction control or stability assist functionality
• improper response from the steering angle sensor.

Probable causes

• Damaged wiring or connectors in the steering wheel angle sensor circuit (shorted, open or corroded)
• faulty steering wheel angle sensor / clockspring assembly
• poor or corroded ground in the steering column harness (shared with the clockspring)
• ABS module ground or communication issues
• impact damage to the sensor or its mounting.

Diagnostic steps

1) Scan the vehicle and record all codes - C1277 often sets together with C1278; on Ford trucks a TSB (08-20-8) covers the traction control lamp on with DTC C1277/C1278. 2) Visually inspect the steering angle sensor wiring and connectors at the steering column; check for broken, bent, pushed-out or corroded pins. 3) Check the sensor ground, which typically ties into the steering column harness and may be shared with the clockspring; inspect the body ground point behind the driver's side dash for corrosion or looseness. 4) Check the ABS module connections and grounds, since the module supplies power and ground to the sensor. 5) With a scan tool, compare live steering angle data against actual steering input. 6) Replace the steering angle sensor / clockspring assembly if the circuit tests good but the signal is faulty. 7) Clear codes and road test to verify.