P0485Fan Power/Ground Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P0485 monitors the supply or ground path of the fan or its control module – not the control line. It is typical of fans with their own module (PWM or LIN), which can report undervoltage or a missing ground. The high currents involved, often 20–60 A, make contact resistance at ground and supply connections and fuse holders the main cause. No manufacturer table available to us lists P0485, so thresholds and warning-lamp behaviour remain open; CARB requires output components to be monitored. The fan then runs intermittently or not at all.
- What you may notice
- Warning lamp (depending on the maker)
- Fan does not run or only intermittently
- Overheating at standstill, weak air conditioning
- Possibly burnt smell or discoloured connector
- Likely causes
- LikelyFan or fan module ground loose, corroded or broken
- LikelyFan fuse blown or fuse holder overheated or corroded
- PossibleRelay power contact burnt – voltage drop under load
- PossibleConnector at the fan scorched, water ingress
- RareFan control module faulty
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €30 – €450
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.