Code Definition

P0A4C (513) — Generator position sensor signal out of range

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

About P0A4C

P0A4C 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 P0A4C 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 P0A4C 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 Toyota and Lexus hybrid vehicles the generator, designated MG1, uses a resolver position sensor to report rotor angle to the inverter assembly and Power Management Control ECU for precise control of generation, engine starting, and power split operation. DTC P0A4C sets when the ECU detects that the sine or cosine signal from the MG1 resolver is outside its expected voltage or amplitude range. The resolver must deliver clean, balanced sine and cosine waveforms to track rotor position accurately, so when either amplitude deviates beyond the specified threshold the ECU sets this code to preven...

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