OBD-II code · Body
B0300 HVAC Evaporator Temperature Sensor Circuit
The HVAC controller reports a fault in the evaporator temperature sensor circuit, used to prevent evaporator icing.
Is it safe to drive with B0300?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyEvaporator sensor failure
- PossibleFaulty sensor connector
Symptoms
- Warning light or symbol related to the affected system
- Comfort or safety function impaired
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.8–3 h
- Emissions test
- Usually unaffected
- Parts involved
- Evaporator Temperature Sensor, HVAC Control Module
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.