P0483Fan Rationality Check
- 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
- Two kinds of cooling fan carry these codes: electric fans switched by relays or driven by a PWM/LIN fan module with speed feedback, and engine-driven fans with an electronically controlled viscous clutch, whose speed a Hall sensor reports – GM calls them EV fans, meaning electro-viscous, not electric vehicle. P0483 checks the fan's function, not its circuit. With a speed sensor (GM viscous fans) commanded and actual speed are compared: GM's Duramax diesels of 2014–18 set it at more than ±500 rpm for at least 120 s, GM petrol SUVs and pick-ups of 2004–06 at more than 1000 rpm – MIL after two trips. Without a sensor Subaru (and the Saab 9-2X) judges indirectly: if coolant at 100 °C or more does not fall within 5 minutes at idle with the fan on, the code sets after two trips. Ford's OBD summaries do not contain it.
- What you may notice
- Check engine light on (after two trips)
- Constant fan roar, or temperature rise at standstill
- Air conditioning weak at low speed
- Likely causes
- LikelyViscous clutch worn or leaking, or its solenoid faulty – fan does not reach or leave target speed
- PossibleElectric fan motor stiff or worn, or fan blocked
- PossibleFan speed sensor or wiring giving a wrong value
- RareRadiator or condenser clogged, coolant low (Subaru logic)
- RareDrive belt slipping (belt-driven viscous fan)
- 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: €150 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.