Turns out a sensor in the boot on the passenger side was the main fault detected by the garage it had been flagged 95 times by the car computer which sounded right. I had a new sensor fitted a few days later and once it had been attached the mechanic noticed the boot error light was still coming up. He opened and closed it a few times and then checked a wire in the boot mechanism. This wire had not come up on the diagnostic like the sensor had and was not flagged as an error by the car. However the three connecting wires for this boot part had all been cut clean off seamlessly he thinks possibly by the boot mechanism turning. They brought the wire out to show me how clean cut it was and also because of how strange it was to happen without appearing on the diagnostic. It had possibly just been touching enough to think it was still connected. They didn't replace the part as it was fine they just reattached it after sorting the wire ends out.
So far I've had no alarm issues, boot warning lights or roof issues since the fix so hoping it stays that way. Thanks again to everyone who offered their input and I thought it would be nice to share what fixed it as too many posts about things breaking on the internet don't go on to actually tell you what fixed it in the end
Original message below.
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Apologies for the long post.
I have owned my 2011 S-drive 23i for 6 weeks and until now without issue bar the alarm going off once randomly the first week according to a neighbour while I was out. Last week when locking my car the boot began to whir continuously as if it couldn't quite lock in place. It had not been opened. I unlocked the car, opened the boot, closed it and locked it all seemed fine.
While driving this weekend however I keep getting the boot open warning light. The first time I stopped to check it and was unable to open it manually I had to use the fob. I closed it and drove off again and still had the warning light this time I kept going and it stopped however it kept happening intermittently. My car alarm has also started to go off, 4 times I know of since the boot issues this weekend. I also had one instance of partial roof close failure but I put it back down from it's half closed position and started again and it was ok.
I wanted to rule out an issue with a low battery so took it to a BMW garage they tested it away from me and said it was faulty and needed replacing. I asked if that could cause the issues I was experiencing. They said maybe and it was good place to start before looking at the boot mechanism which they said was fine when they tried it. They said my model of car needs an AGM battery specifically rather than a regular battery and it would be £300 for the battery + £45 fitting.
That sounded a lot so I went for a second opinion which complicated things further they did a battery test that said the battery was good. I told them about the conflicting result and they didn't think my current battery was an AGM one either as it would usually say on it. They had someone who knew more about BMW's come have a look. He did 2 battery tests, one in a mode called SAE said it was good but the test using EN said replace.
I went to a 3rd garage which again gave the same mixed result depending on SAE or EN.
None of them could say if the battery was leading to the issues with the boot but it's looking like it may be an issue in itself.
Given the range of issues I'm experiencing has anyone ever had a battery cause so many problems including the boot issue? The car is 7 years old and it's the original battery apparently so I'm thinking it's likely and worth checking before I replace anything in the boot?
Any advice or experience appreciated.
