Code Definition

B0159 — Ambient air temperature sensor signal out of range

System: Body  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About B0159

B0159 is a generic (obd-ii standard) body diagnostic trouble code. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

When B0159 is stored, the module has detected a plausibility fault — the measured value is in the electrical range but is not consistent with expected operating behaviour; 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.

Because B0159 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

DTC B0159 sets when the HVAC or body control module detects that the ambient air temperature (AAT) sensor signal is out of its expected operating range. The AAT sensor is a negative temperature coefficient (NTC) thermistor, typically mounted behind the front grille or front bumper, whose resistance falls as temperature rises. The control module supplies a 5-volt reference through a pull-up resistor and reads the voltage drop across the sensor to calculate ambient temperature, which is then used by the climate control system, the displayed outside temperature reading, and various engine and tra...

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