2018 Citroen Berlingo - Serviced and now a P2100 error

[Tetsu0san]

Hi all

I've just done a first service on a 2018 Berlingo 1.6 diesel (oil, oil filter, fuel filter, air filter) and now I've got a P2100 error. Control of the air mixture open circuit. Temporary fault.

I can clear the error, stop and start the engine and it goes away, but leave it for a couple of minutes and then when I start it it comes back.

I've retraced my steps with all the sensors that I removed and plugged back in, and I can't see anything obvious at all. I was a little stupid because when I first plugged the diagnostic in (a TopDon Phonex Pro) I ran a quick scan, saw a couple of errors and cleared them without taking much notice. One of them I'm sure was an EGR stuck which I can't remember if it was open or closed, but that cleared.

Does anyone have any ideas? Apart from this being an issue that's been there for a long time, I can't see what it could be. I did notice that on the the connector on back of the throttle body (and indeed most of the connectors I looked at) had the locking tab broken so there was only luck holding it in place, so I secured that with a cable tie, but only after seeing the error code. So I can only presume someone who was in there before me was a little heavy handed with the plugs. I also noticed quite a bit of dirt in the fuel filter housing which I initially thought could have been metal from the pumps, but it wasn't. Just dirtier than I would have expected.

I'm really starting to pull my hair out now!

:Edited to fix the silly spelling mistakes.