C0840Air Suspension Solenoid Valve Circuit
- Generic OBD-II code · Chassis
- Can trigger limp mode
- How the car detects it
- C0840 is not documented anywhere in public; no list, bulletin or manual of any carmaker uses it. The title concerns the electrical side of the valves that route air in a self-levelling suspension. Some systems carry one switching valve per air spring in a central block next to the compressor, as in a Continental patent that also places fast lowering valves there; older Ford and Lincoln designs put a two-position vent solenoid on top of each spring, opened by the vehicle dynamics module to fill or vent. A circuit fault means the module sees an open, a short or wrong current on a coil. Bentley logs such a case as C11C613, an open circuit at the rapid filling valve of the Bentayga, and checks the connector first. The affected corner can no longer be raised or lowered.
- What you may notice
- Air suspension warning or service message
- One corner sags or ride height cannot be changed
- Likely causes
- LikelyWater or corrosion in the valve connector (Bentley 2064579/1 checks the plug first)
- PossibleOpen or shorted valve coil, often after moisture got into the system
- RareChafed harness at the valve block or air spring
- Repair
- Medium · Usually a job for a workshop.Typical cost: €100 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.