Fans trying to take off

Hi all,

Looking for a bit of advice on an issue with my 2018 SQ7 that I can’t quite pin down.

The car drives perfectly. No overheating, temperature stays bang on where it should be, and there are no issues at all while driving.

The problem only happens after the car is switched off.

After a short run, once I park up and turn the engine off, the cooling fans will sometimes come on after a short delay and run at full speed. It doesn’t happen every time, but when it does they can run long enough to completely flatten the battery, which has already happened once.

A few key things I’ve noticed:

It’s intermittent, not every drive
The fans don’t come on immediately, there’s a delay after shutdown
If I start the car again, the fans stop straight away
If I then switch it off again, they usually stay off
Engine temperature is always normal when driving, no warnings or signs of overheating

Because the battery went flat, I’m expecting there to be a load of fault codes stored that probably aren’t relevant to the actual issue.

To me it feels like the after run cooling is being triggered when it shouldn’t be, almost like the car thinks it’s hotter than it is once it’s switched off. The fact it corrects itself as soon as the engine is started again makes me think it’s either a dodgy temperature reading or something in the control logic rather than a physical fan or relay fault.

I’ve had a look around the forums and seen a few posts about fans running after shutdown, but nothing that quite matches this behaviour, especially the part where restarting the car immediately stops it and then it behaves normally again.

Has anyone seen anything similar on these, or got any ideas where to start looking?