Powertrain
generic / SAE
P256A
Engine Idle Speed Selector Sensor/Switch Circuit/Open
The idle-speed selector input is open. On commercial vehicles this switch lets the operator pick a fast-idle setpoint (for example to keep auxiliary loads supplied). With the input broken, the ECM cannot apply an operator-selected idle speed.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number5 / 6A
Possible causes
- Open wire or unplugged switch high
- Pin pushed back out of connector body low
- Cracked solder joint inside the module or sensor low
Symptoms
- Check engine light on
- Idle speed too high, too low, or unstable
- Possible stalling at idle or after cold start
Inspection / repair
- Difficulty: medium
- DIY: possible
- Estimated cost: 60–350 €
- Estimated time: 0.3–1.5 h
- Component: idle speed selector switch
- Component: wiring harness
- MIL / check engine light
Sources
References
sae:J2012