P0818Driveline Disconnect Switch Input Circuit
- Generic OBD-II code · Powertrain
- Can trigger limp mode
- How the car detects it
- P0818 concerns a switch input that reports whether the driveline is disconnected – on four-wheel-drive vehicles typically the neutral position of the transfer case or an axle disconnect, on hybrids a disconnect clutch between engine and transmission, as a Ford patent uses the term. It matters for OBD because in transfer case neutral the engine runs without load and wheel speed does not match the ratio, so misfire, ratio and vehicle speed monitors must know about it; CARB requires monitoring only then. The check would be a circuit or plausibility test against the speed ratio. No manufacturer document available to us uses P0818, and which of the two meanings applies cannot be proven. All-wheel drive or neutral may then be unavailable.
- What you may notice
- All-wheel drive or neutral cannot be selected
- 'Service 4WD' or similar warning
- Possibly check engine lamp (depends on manufacturer)
- Likely causes
- LikelyNeutral or disconnect switch at the transfer case or axle faulty
- LikelyUnderbody wiring or connector corroded or damaged
- PossibleTransfer case actuator does not reach its end position
- RareControl module or software
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.