Fan permanently on and CEL

[hotpurple]

Hi all,

My S2 Elise has developed a curious issue where the CEL is permanently lit and the fan runs from about 30s after the engine starts (stone cold) to a few seconds after the engine stops. Any ideas what to look for to fix it? There’s no codes shown when I plug the code reader into the OBD port. 

[MrWill]

Hi hotpurple

I'm no expert on elec-trickry but I've usually resolved issues before getting an expert in by just doing the basics

Check all your connections  for good fit and corrosion. Check for good earth etc

If it was me I'd summise the fan coming on 30s after engine on means the ecu thinks the engine is hot so why not the obvious of a faulty temp sensor on the engine sending a false signal?

Good luck

MrWill

[hotpurple]

Thanks for the advice, you’ve had pretty much the same ideas as me. We’ve changed the temperature sensors (both of them) so my only thinking now would be a dodgy connection in the loom somewhere. Luckily, I have a OBD code reader that can show live values from the various sensors on the car, so I’m going to plug that in and see if the ECU thinks the temperature is doing something odd (open circuit maybe).