Code Definition

B1254 — Air Temperature External Sensor Circuit Failure

System: Body  |  Type: Manufacturer-Specific  |  Make: Generic

About B1254

B1254 is a manufacturer-specific body diagnostic trouble code. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

When B1254 is stored, the module has detected a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: Body (B) codes are often stored in the body control module, airbag module, or climate module. A basic OBD-II tool usually will not read body codes — an enhanced or OEM-level scan tool is typically required.

B1254 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

The external air temperature sensor, commonly called the ambient air temperature sensor, is typically mounted behind the front grille, inside the front bumper cover, or under an exterior mirror, positioned so it reads outside air temperature without heat soak from the engine or exhaust. The sensor is a negative temperature coefficient (NTC) thermistor whose resistance varies with temperature, returning a voltage signal to the climate control module that the module compares to a lookup table to determine ambient temperature. DTC B1254 is set when the climate control module detects the sensor ci...

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