Code Definition

P0A90 (604) — Drive motor A performance

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

About P0A90

P0A90 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 P0A90 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.

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 P0A90 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 hybrids the inverter drives Motor Generator 2 (MG2), the traction motor known as Drive Motor A, and the hybrid vehicle control ECU monitors the feedback that confirms MG2 is responding as commanded. This manufacturer subcode of P0A90 sets when the ECU finds an inconsistency between the commanded drive signals and the resulting voltage, current, or rotational response from MG2. It points to an inverter output control or feedback monitoring problem, often in the phase control feedback or current monitoring circuits, rather than a purely mechanical or position sensor fault. Sy...

Join TaT to view the complete code information and diagnostic details.

Quick Facts