Code Definition

P0A42 — Drive motor A position sensor signal high

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

About P0A42

P0A42 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 P0A42 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 P0A42 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

Drive Motor A uses a rotor position sensor, typically a resolver, to give the inverter rotor angle for timing and phase control of the traction motor. The module monitors the level of the position signal, and DTC P0A42 sets when that signal voltage rises above the calibrated upper threshold. A persistently high signal most often reflects a short to a voltage source on the signal circuit, a reference or ground fault that lifts the monitored level, or a sensor fault, rather than a valid rotor angle. With the level stuck high the inverter cannot resolve rotor position, so it will derate or disabl...

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