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DTC codes / P25xx · Vehicle speed, idle control and auxiliary inputs / P256E

P256EEngine Idle Speed Selector Sensor/Switch Circuit Intermittent/Erratic

P256E indicates that the powertrain control module (PCM) has detected an intermittent or erratic signal from the engine idle speed selector sensor or switch circuit. This selector is typically part of a system that allows the driver to choose different idle speeds or operating modes, and the PCM expects a stable, predictable voltage or resistance from it. The code is set when the signal drops out, jumps, or behaves in a way that does not match the commanded state, often due to a poor connection or a failing switch.

SystemPowertrain
Code typeGeneric (all makes)
SeverityLow
Fix difficultyIntermediate
AreaVehicle speed, idle control and auxiliary inputs

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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