Gah, short subject line box..

Sometimes (increasingly) the RRS is refusing to lock on the first try with the familiar high pitched "plip plip" that indicates it thinks a door/bonnet/boot is not closed properly - annoyingly (of course) it never does it when I can see the dashboard to see if it tells me which door/bonnet/boot is not closed properly, and usually hitting the lock button a second time results in the car locking itself happily, without anything having been opened or closed.

Can IIDTool or similar interrogate the central locking ECU to see what the last recorded failure is? I haven't got my IIDTool handy (long story, it's still at a friends house ) to check

I know it's "probably" the bonnet sensors as they are a common fault, but the change in behaviour also seems to have coincided with a change of interior lightbulb (to change a crap LED unit the previous owner fitted that flickered with a new LED unit that isn't failed) and maybe it just doesn't like the "CANbus safe" LEDs.. but that seems odd! 2014 BMW 530d Touring, 2006 BMW 650i, 2018 Mini Cooper S

Had this recently on mine and it turned out to be the drivers door lock. There is a visual way to tell if its one of the door locks without scanning for codes. When i was locking mine the smaller handle above the door pull would not pull in fully indicating that that was the faulty unit. So try locking the doors with the fob (you can do this with the windows down for ease of viewing) and look at all the short handles to see if they are all pulled in the same distance. It should be fairly obvious if its one of these. If its the bonnet switch the car still locks most of the time but the alarms will sound intermittently to indicate switch failure. Theres no guarantees with these methods they are just my findings through issues i've had.
If it is one of the door locks, make sure you order the correct one. The non smart key versions are a lot cheaper.

Good tip! I'll lock/unlock a few times and pay attention to the handles I had the rear passenger lock assembly replaced last year at the MOT (it was failing to unlock) so it could be one of the others following suit - or of course, a faulty replacement. 2014 BMW 530d Touring, 2006 BMW 650i, 2018 Mini Cooper S

It did it last night - looking through the doors it doesn't look like any of the door locks are attempting to move.. of course, I forgot to look at the dashboard to see if the speedo cluster told me anything at the same time  2014 BMW 530d Touring, 2006 BMW 650i, 2018 Mini Cooper S

My 12MY doesn’t work like that, if it detects an issue it doesn’t even try and lock the doors, it will just peep peep as if it’s a door ajar rather than a lock. If on the odd occasion mine does it, I just open and close the doors that have been used and it’s normally my driver door. 2019 5.0 SC SVA (Current)
2012 5.0 SC AB. Sadly written off by a campervan
23 plate Focus ST (Current)
1942 VEP Ford GPW Jeep (Willys) (Current)
1943 Whites M16 Halftrack (Current)
16 plate Eurofighter Typhoon, 2 x Eurojet engines with 20,000lbs thrust each. 1380mph

Yeah - on the odd occasion it hasn't locked on the second press, that's what I've taken to doing.. not always the same door, but opening & closing 'a' door seems to cure it. Of course, it could be a sticky switch on any other door and maybe the vibration from shutting the door nudges the switch.

When I get the IIDTool back I'll see if that can tell me what the last failure reason was 2014 BMW 530d Touring, 2006 BMW 650i, 2018 Mini Cooper S

usually the bonnet catch is the culprit on an L320