Code Definition

B1253 — Air Temperature Internal Sensor Circuit Short To Ground

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

About B1253

B1253 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 B1253 is stored, the module has detected a short-circuit (voltage pulled to ground or to supply) in the monitored circuit; and 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.

B1253 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 internal air temperature sensor is part of the climate control system and measures cabin air temperature, typically by drawing air across the sensor element with a small aspirator fan mounted inside the dashboard or overhead console. The sensor is a negative temperature coefficient (NTC) thermistor that varies its resistance with temperature, providing a voltage signal back to the climate control module that scales from high at cold temperatures to low at warm temperatures. DTC B1253 is set when the climate control module detects that the sensor signal voltage has fallen to near zero, indi...

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