Electric cooling fan coming on unexpectedly

[ChasW]

For some reason the cooling fan on our 2008 Peugeot 207 1.4 petrol came on after a short drive the other day. It's never come on in the past. It runs for about 5-6 minutes after stopping the engine and happens every time I start the engine whether I drive off or not. It runs while the engine on as well. I can tell because it's an additional sound above the normal engine noise. Is this something to do with the thermostat? Any suggestions would be appreciated.
(Also posted on general gassing)

[Steve_D]

Sounds like a sensor has failed.
There may be other issues as the fan is normally controled by the ECU on modern cars. If the sensor has failed the ECU may be doing other things like changing the fueling and ignition because it thinks the engine is running hot.
Code reader time I think.

Steve

[ChasW]

Thanks Steve. Looks like a trip to the garage.

[ChasW]

Took it to Peugeot indie. ECU believes the engine is running hot. No fault found with cooling system so re-programmed ECU and problem fixed. Cost me £100 though!