Code Definition

P0A73 (326) — Generator A phase V current sub sensor signal out of range

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

About P0A73

P0A73 is a generic (obd-ii standard) powertrain diagnostic trouble code recorded for Toyota vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P0A73 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: 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 P0A73 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

On this Toyota hybrid Generator A is the motor generator that produces electrical power for charging and the traction system and also cranks the engine, and the MG ECU monitors its U, V, and W phase currents using sensors integrated into the inverter assembly. A sub sensor provides a redundant cross check of each main sensor for accuracy and functional safety. DTC P0A73 sets when the MG ECU detects that the Phase V sub current sensor signal is outside its calibrated range. This can be caused by a faulty sub sensor, an open, short, or high resistance in the signal or ground wiring, a reference ...

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