P256D Possible Causes
- Faulty engine idle speed selector sensor/switch
- Engine idle speed selector sensor/switch harness is open or shorted
- Poor electrical connection in engine idle speed selector sensor/switch circuit
How to Fix Code P256D
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
Possible Symptoms
Illuminated engine light (or service engine soon warning light)
P256D Meaning
The Engine Control Module (ECM) monitors the signal from the engine idle speed selector sensor/switch circuit. The ECM sets the OBDII code when the engine idle speed selector sensor/switch signal is outside factory specifications.