P256EEngine Idle Speed Selector Sensor/Switch Circuit Intermittent/Erratic
- Generic OBD-II code · Powertrain
- How the car detects it
- P256E records an idle speed selector signal that drops out or flickers for short moments, more often than real switch use would cause. Since the selector is usually operated with the engine idling for long periods, engine vibration, a worn rocker switch or a loose crimp can be enough; each interruption can cancel the raised idle and make the engine fall back and rise again. Ram's 2012 chassis cab guide describes an Idle Up set speed that is entered when the function is activated, so repeated on-off events are noticeable as speed changes. No manufacturer publishes P256E. CARB requires circuit faults on monitored inputs to be watched continuously. A steady break would set P256A instead. The driver mainly notices an unsteady raised idle.
- What you may notice
- Raised idle drops out and comes back
- Engine speed rises and falls at standstill
- Code stored only intermittently
- Likely causes
- LikelyWorn rocker or toggle switch
- PossibleLoose crimp or terminal in the selector circuit
- RareHarness moving with engine vibration at idle
- Repair
- Easy · Often possible to do yourself.Typical cost: €20 – €250
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.