Code Definition

P0A3F (243) — Drive motor A position sensor signal error

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

About P0A3F

P0A3F 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 P0A3F is stored, the module has detected 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 P0A3F 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 hybrid systems Drive Motor A, commonly MG2 in the hybrid transaxle, uses a resolver as its rotor position sensor, and the Power Management Control ECU relies on it for precise torque and rotation control. The resolver works from an excitation signal and returns sine and cosine feedback that the ECU converts into rotor angle. DTC P0A3F sets when the ECU detects that these outputs are missing, out of phase, or show an implausible relationship between the sine and cosine signals, indicating a loss of signal integrity or a problem with resolver excitation. Because the ECU can no longer c...

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