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.
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.
Common causes
- high
Ambient temperature sensor failed
One of the most commonly reported causes for this code — check this first.
Typical part cost: $30-170
- medium
Wiring or connector fault to sensor
A plausible cause — test and verify before replacing parts.
Typical part cost: $30-170
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First things to check
- 1Confirm the code with a scan tool and check for additional related codes.
- 2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.
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Related codes
See related trouble codes
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Frequently asked questions
What does B0040 mean?
B0040 means "Outside Temperature Sensor Circuit". It is a generic OBD-II code that points to a fault in the body.
What are the most common causes of B0040?
ambient temperature sensor failed; wiring or connector fault to sensor — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.
Can I keep driving with this code?
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical. Use the Wrenchify app for a full diagnosis specific to your vehicle.
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