C1178: Speed Wheel Sensor LR Coherency Fault

MediumChassisWheel Speed Sensors

What does C1178 mean?

C1178 is a diagnostic trouble code indicating "Speed Wheel Sensor LR Coherency Fault". A sensor in the wheel speed sensors is reporting abnormal data or has lost communication with the ECU. Sensors can fail due to age, contamination, heat exposure, or wiring issues.

Common causes

  • Faulty wheel speed sensors component
  • Wiring or connector issue in the related circuit
  • Failed sensor providing incorrect readings
  • Software/calibration issue requiring ECU update
  • Related component causing secondary fault

What should you do?

Schedule a diagnostic appointment at your earliest convenience. The vehicle is generally safe to drive short distances, but the underlying issue should be addressed to prevent it from worsening.

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Code C1178 can mean different things depending on your vehicle. TorqueBot gives you a diagnosis specific to your make, model, and year.

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Related codes

C1176Speed Wheel Sensor LR Circuit Open
C1175Speed Wheel Sensor LR Input Circuit Failure
C1168Speed Wheel Sensor RR Coherency Fault
C1166Speed Wheel Sensor RR Input Open Circuit