Code Definition

P0A25 — Alternator torque sensor signal high

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

About P0A25

P0A25 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P0A25 is stored, the module has detected a signal or supply voltage higher than the expected operating range; and a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P0A25 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

The powertrain control module monitors the alternator torque sensor, which measures the mechanical torque input to the alternator and is an important parameter for charging and energy management on hybrid and stop start systems. DTC P0A25 sets when the module detects the sensor signal voltage exceeds the upper calibrated limit and remains there beyond a defined period. A signal high condition is typically produced by a short to voltage, an open in the ground circuit, or a failed sensor rather than a genuine torque event. When the code is set the vehicle may show erratic charging, unstable idle...

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