P256E code meaning
Engine Idle Speed Selector Sensor/Switch Circuit Intermittent/Erratic
What P256E means
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.
P256E at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P256E
- Raised idle drops out and comes back
- Engine speed rises and falls at standstill
- Code stored only intermittently
Common causes of P256E
- Most likelyWorn rocker or toggle switch
- PossibleLoose crimp or terminal in the selector circuit
- Less likelyHarness moving with engine vibration at idle
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Idle speed selector switch
What each part of P256E means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 5 | Area: vehicle speed, idle control and auxiliary inputs. |
| 6E | The exact fault in that area. |
What to do next
- Note P256E and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P256E
What does P256E mean?
P256E means "Engine Idle Speed Selector Sensor/Switch Circuit Intermittent/Erratic". P256E records an idle speed selector signal that drops out or flickers for short moments, more often than real switch use would cause. It is a generic code, so it means the same on every make.
Is it safe to drive with P256E?
P256E does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will P256E fail an emissions test?
P256E is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is P256E to fix?
Difficulty: easy. A typical repair takes 0.3 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P256E clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.