B1966: A/C Post Heater Sensor Circuit Failure
MediumBodyClimate Control
What does B1966 mean?
B1966 is a diagnostic trouble code indicating "A/C Post Heater Sensor Circuit Failure". A sensor in the climate control 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 climate control 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.
Get a diagnosis for YOUR car
Code B1966 can mean different things depending on your vehicle. TorqueBot gives you a diagnosis specific to your make, model, and year.