HVAC Temperature Sensor Circuit Range/Performance Problem
The HVAC system is detecting an issue with the temperature sensor.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The HVAC system has a temperature sensor that tells it how hot or cold the air is. If this sensor is malfunctioning, it can't regulate the cabin temperature properly, leading to extreme heat or cold inside the vehicle.
What the computer is actually seeing
The computer monitors the voltage from the temperature sensor, expecting a range typically between 0.5V to 4.5V as the temperature changes. It notices values either outside this range or not changing as expected.
What a healthy reading looks like
Sensor voltage should be within 0.5V to 4.5V corresponding to temperature readings from -40°F to +230°F.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check the HVAC temperature sensor wiring for breaks or fraying. Decision: If the wiring appears damaged, repair it and retest.
- 22. Inspect connectors for corrosion or loose connections. Decision: If connectors are damaged, repair or replace them and retest.
- 33. Measure the voltage at the temperature sensor while the vehicle is running and compare to the expected values. Decision: If the voltage is outside the 0.5V to 4.5V range, replace the temperature sensor.
- 44. Check for any other DTCs related to the HVAC system that may provide additional context. Decision: Address any additional fault codes found before proceeding.
Common causes
- Faulty HVAC temperature sensor
- Wiring issues in the sensor circuit
- Corroded or loose connectors
- Software calibration problem in HVAC control module
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Yes, but climate control will be affected. Make it a priority to diagnose it soon.
Will this code come back after fixing it?
If the root cause is addressed, it shouldn't return. Always clear codes and retest after repairs.
Why does this code sometimes pair with B1401?
B1401 indicates a similar sensor issue, so if one sensor fails, the other may also be affected.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
Start guided diagnostic →