308 2018 U1218 fault

[Tottie88]

Hi guys spelling not the best but here goes.


I have a fault on my car after a pulled a fuse fuse out i was looking to see if the aircon fuse had gone but it was ok. After putting it back in a fault came up and saying engine fault get repaired.

The only thing that has stopped working is the stop and start.

I have been with the auto electrician all morning for him to tell me a need a new BSI unit or could semd it off for a rebuild? My question is could it be more simpler to repire replace a cable ? Does a new BSI need programming or is it a case of unplugging the old one buying a new one and plugging back in?


Could i just live with on stop start and it not cause more faults over time ?


Thanks rich

[GiveMeABreak]

Hi Rich

No, you can't just swap a BSI - it has to be programmed for the vehicle as it's basically the brains that interfaces and controls all the other units.

But I would hold fire for a minute as there's nothing so far to suggest a new BSI is needed. A fuse is a fuse and would blow if there was an overload anywhere.

As for the Stop and Start, that system will only work if the battery is at sufficient charge and also has a lot of other conditions that need to be met for that system to work - so if everything else is working, I would ignore that and leave it.

[Tottie88]

Hi marc,

The electrician did aload of diagnostic test would this of not showed a blown fuse ? All fauts were clear and only the u1218 fault remained after he did a BSI reset.

[GiveMeABreak]

I was just saying if it was a blown fuse, that could be easily replaced.

Does the engine fan operate permanently too with the engine running? - have a check. If this is the case and with that message you mentioned, along with this fault code, it may be a faulty outside temperature sensor. This would also affect the Stop Start as it relies on the temperature when it decides to operate or not.

[Tottie88]

Thanks, am just at a real loss on what todo next. I would like to resolve it. Guess i will have to pay the main deal to have a look ?

[Tottie88]

Other thing is the fault comes on straight away befoe the engine turns over if that helps ?

[GiveMeABreak]

Can you answer my question regarding the fan in my last post?

U1218 can have different possibilities depending on the associated issues, which is why I asked.

[Tottie88]

Can i ask how i check this ?

Are you wanting to know if the can comes on when the engine is running and then gors off when the engine does ?

[Tottie88]

So update the trophy of biggest tit can go to me....

The fuse i pulled out i put back in the wrong place!

I wont be touching anything else on my car lol

[GiveMeABreak]

Well done - lesson learned, thanks for the update.