The BC1 (Body Control Unit)

To access the BC1 Unit:
Pull off the rubber door seal (drivers side UK) along the lower sill / doorstep, then carefully prise away the plastic trim panel along the inner sill / front footwell trim with a large scewdriver / rag to protect paintwork. In the interior photo below you can see the large round white nylon clips in the bodywork which hold the trim. If you wish to completely remove the trim some find it easier to remove the seat and lower belt mounting. (I normally manage to gain enough access without though).

Reconditioned Exchange BC1 (Body Control Module) are now available from BBA-Reman £100-150 which is a lot less than a new unit from BMW :thumbup1:

See Link Below:
http://www.bba-reman.com/catalogue/DetailedProduct.aspx?DetailedProduct=1414

hi i have a 51 reg cooper a few months ago the passenger side door would only lock and not unlock with central locking, then the head unit fuse went and i acidently took out the lock fuse and put it in the head unit fuse slot thinking it was a spare fuse, then i put a new fuse in the lock one, after that no sides would lock inc boot and only the drivers side would unlock, i tested and theres voltage to the motor plugs but no voltage when the button on the fob is pressed on any terminal. i had it plugged in on diagnostic and it showed faults on the locks, rear wiper and a few other bits, the body control unit controls both these doesnt it? thats whats making me think its the body control unit at fault. on the diagnostic the electrician could use his machine to lock and unlock the doors but it wasnt working but on his machine when he pressed dead lock doors both locks would lock, doesnt the dead lock work off a different circuit to the body control unit?i took the side panel off to access the body control unit and it has a cover over it. does this mean it will have been recalled once? tonite went to the car and now the drivers side is locking and unlocking and passenger side is locking. the passenger side still wont unlock.do you think water could be still causing this? as it stopped working and now working again, maybe could have dried out. appreciate any help thanks

Useful BC1 post by 'unmmalterman' on MINI2.com .......thought it worth adding here in full for future reference!

Weird Electrical problems:
Hi! I'm no expert, however, my son-in-law who knows absolutely nothing about cars, has a 2003 R53 S which I sourced & bought on behalf of my daughter (nice 30th birthday present, eh!) he lives in London and was experiencing similar odd lights flashing, window dropping, etc., but mainly rear brake lights coming on after lock up, sometimes side lights, and dash going crazy.

All this drained the battery so he tried the 'local' garage who gave tales of woe and suggested the speedo had been diddled by the previous owner, the diagnostic (generic code reader) gave the fault as "serial module connection -dashboard".

(I researched THIS forum and the BC1 module mentioned by mab01uk seemed to be the culprit.) Son-in-law then took the car, at my suggestion, to a BMW main Stealer for a definitive diagnostic test...£198 charged for the hour! oops.
Together with a long list of sundry faults (not asked for) which totalled......ready?........£6,514 to fix. ha ha.

(Tip:To continue using the car, disconnect the battery earth in the boot and lock up manually, in the morning, unlock drivers door, pull the ring under back seat to open boot and re-connect battery. Irksome, but keeps you going.)

I therefore towed the mini, with my 65yr old wife, 220 miles to Lancashire and said I'll sort it. Found the mysterious BC1 box down by the drivers right foot, (easy! -undo seat belt mount/pull off trim along sill/undo 10mm nut/black box pulls off./#4 connectors from loom/loom is wrapped in daft cloth tape, which is wet, this is the cause, water leaks in via windscreen seals, down loom into BC1 and it also then sucks water up from the wet floor (capillary action). I stripped the cloth insulation off and used proper plastic ins. tape just to band the wires together.)

Now, one garage chap I mentioned this to said it's possible, maybe, to actually dry out the box using heat & hair dryer, then replace the plug in connections (which have a sort of sliding sideways action) this is a long shot but would therefore, cost you nothing if it then works ok. If not......

The next stage, without taking the module off, is to buy a replacement, on ebay used ones are around £55, I got a brand new, unused one for £120! Next it must be taken to a garage (not BMW,unless you're loaded) who specialise in re-programming such black boxes, I went to North West BMW in Horwich, Lancashire and they simply unplug then re-plug new module in, then use laptop to re-program it to your existing keys. They have to take readings from the faulty one first so DON'T UNPLUG IT YOURSELF! your keys won't work with the new module so you'd be stranded. For this they charged £65 but don't quote me on that, I think, ahem, it should have been more. (They give fantastic, honest service and really know their stuff)

Anyhoo, all done, no further problems. It seems it's an acknowledged fault on the mini and apparently the cure is to.....ready?.......wrap it up and seal it in a polythene bag. I'd suggest wrapping self-amalgamating, waterproof electrician's tape very tightly round the wire bunches and then tie-wraps around whatever polybag used, but very tight, water creeps everywhere!!

This was a big mystery to me before, and certainly scared the **** out of my daughter & sil, with hindsight, it's actually very easy.

I'm working on some of the absolutely ludicrous list from BMW as some of it's MOT stuff, which has run out. However, the original main fault was cured for £185 but could be a lot less if using a 2nd.hand module, or even nothing if you're lucky and do as I did. Good Luck. I think this is my first posting on here so hope it's clear and useful. Cheers. Tom.
Electrical Problem Please Help - MINI Cooper Forum - MINI2 Mini Cooper Forums


Brake Lights stuck on?
Maybe damp in the BC1 or a wet diode......
brake lights stuck on? - Page 5 - MINI Cooper Forum - MINI2 Mini Cooper Forums

Mini Cooper ECU replacement
"I managed to track down a seller who specialised in Mini spares and found a second hand ECU at the bargain price of £100 complete with Key, Barrel and EWS from the same vehicle. I was feeling quite pleased with myself for tracking down such a bargain and once the ECU and other bits were fitted the car ran perfectly.

Great i thought! until i got out of the car when i got home and tried to lock the car! The new key failed to lock the doors or open them for that matter once i'd locked them with the original key.

I did a quick check on the net and found a few threads with various techniques for programming keys, however none of these worked. In the end i took the car to a BMW specialist i know (Yes - should have gone here in the first place!) where he told me that when you change an ECU not only do you need the Key, Barrel and EWS from the donor car you also need the BC1 unit or Body Control which is also coded to the ECU and Key!
Luckily the company who sold me the ECU still have the BC1 from the same vehicle and are sending it out to me know.

I've since searched on Google and various forums and have not found any mention of needing the BC1 as well as the parts from a donor car. So i thought i'd post this as a warning to anyone else who needs to replace an ECU, and to see if anyone has had a similar experience of this?"
Mini Cooper ECU replacement - MINI Cooper Forum - MINI2 Mini Cooper Forums

An interesting damp BC1 case and it's solution below as recently reported on MINI2.com:
Dashboard lights not working?
Dashboard lights not working? - MINI Cooper Forum - MINI2 Mini Cooper Forums


The General Module (BC1)
A few posts ago, I looked at the bus systems within the MINI electronics and how it lays the groundwork for the specific modules that send and receive communications along the data paths:
There is a BUS in my MINI ! - Mini Cooper Register Forum

Now its time to review the function of the General Module.

The General Module or as it is often referred to as the Body Control Module or BC-1. It is the module that manages a number of specific vehicle systems and is located behind the passenger kick panel just in front of the door.

It has two primary K-bus connections, one to the Instrument cluster and one to a network bus. This body control module is a consolidation of a number of smaller system modules that control and monitor the following systems: drive-away protection, locking systems, rain-sensing wipers, sun roof, park distance control, mirror control, audio systems, navigations system, keyless entry, power windows, xenon headlamp control using the leveling sensors, run-flat warning system, all interior lighting, and the multi-function steering wheel. The control module also manages the anti-theft alarm systems if installed and the keyless entry system and its RF receiver.

Although the K-bus is a fairly slow, it is event driven. Messages sent out by the Body Control module have the highest priority on this bus and will override other K-bus traffic . As noted in previous discussion, messages are distributed to all devices but only the specific module being addressed responds to the unique message and subsequently react. This is similar to a computer network where messages are sent to all devices, but only a specific IP address, like a printer, actually responds to the command. As seen in an earlier article here, the General Module is connected to both the K-Bus and Instrument Control Cluster, which in turn is a part of the D and DS-2 Bus infrastructure.

The General Module manages the lock/unlock functions, tailgate release, fuel filler cap and convenience opening of windows and sun-roof, when you hold the door unlock button down for more than five seconds. The drive-away protection or electronic immobilizer - referred to as EWS or Electronic Watchdog System - makes it impossible for the engine to be started by any method other than using the specific keys provided with the vehicle. This operates by matching a primary code that is programmed into a chip set, located in the vehicle's key and into the General Module. A secondary code is changed every time the vehicle is started and stored in the key each time. If they do not match, the engine management control module and the starter are disabled. The key communicates back and forth with the system by way of a transponder in the key and a ring antenna that surrounds the steering lock cylinder. If you bring the body of your key up close to the ignition switch, with the driver's door open, you can hear the familiar chime, even though the key is not in the ignition.

This drive-away protection system can support up to 10 keys for one vehicle. Only a MINI dealer can provide replacement keys and is capable of canceling the electronic authorization codes, in the event of a stolen vehicle being recovered and re-keyed using the BMW scan and diagnostic tools DISplus, GT1 or MoDiC

The General Module, is a sophisticated device capable of controlling all of the body electronics and has an integrated diagnostic system capable of reporting a number of faults to the OBD connector located in the driver's foot well. This is the connector that your MINI dealer ties into to conduct fault location and analysis and fix an ailing MINI.
(Posted by murmini on 31 December 2006)
murmini - MINI Cooper Blog : The General Module