OBD-II code · Body
B0040 Outside Temperature Sensor Circuit
The HVAC or body control module has detected an implausible signal from the outside (ambient) temperature sensor. The displayed outside temperature may be wrong or missing and automatic climate control may behave incorrectly.
Is it safe to drive with B0040?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyAmbient temperature sensor failed
- PossibleWiring or connector fault to sensor
Symptoms
- Warning light or symbol related to the affected system
- Comfort or safety function impaired
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.3–1 h
- Emissions test
- Usually unaffected
- Parts involved
- Outside Temperature Sensor, HVAC Control Module, Body Control Module
Related codes
- B0039Second Row Right Frontal Stage 1 Deployment Control
- B003ASecond Row Right Frontal Stage 2 Deployment Control
- B003BSecond Row Right Frontal Stage 3 Deployment Control
- B0041Third Row Left Frontal Stage 1 Deployment Control
- B0042Side Deployment Loop Open (Generic)
- B0043Third Row Left Frontal Stage 3 Deployment Control
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.