BCU fault symptoms? Wipers on with engine off?!?!? etc etc!!!!
2 sets of symptoms for you on my 2006 ('56 plate) Mini Cooper R50. Car done 70000miles.
NB Both these have happened after wet weather:
1: Couple of weeks ago:
Car would not unlock off the remote key. Had to manually unlock the car. Got in the car, it wouldn't start. When i took turned the ignition off, the ignition lights would stay on (basically more or less every light on the dash, as you'd get when turning the ignition on to start the car).
Also noticed the brake lights were on permanently!
Tried starting the car a few times to no avail.
A few minutes later, tried again. Car started. Success. Brake lights were off.
But, when i turned the key back to the off position, the car kept running. It kept running even when I took the key out.
Left car engine running, heater on hot, blowing to the floor position (suspecting dampness around the BCU).
This sorted the problem until today.
2: Today, drove as normal to work. But heavy rain and some big puddles on the road. Switched off at work, locked car as normal. Two hours later the porter told me that my wipers were on. Went to the car, the wipers were indeed 'on'. Started the car to make sure the battery wasn't draining too much. Started fine. Wipers went off (Wiper switches were in off position anyway).
Switched off the car, the bloody wipers start up again. Only way to stop this was to take out 2 fuses in the front passenger compartment, one 5A and one 20A. This stopped the wipers. Fuses back in
Drove home, Car as normal.
Took off the inner sill trim panel, BCU seems dry as a bone?
My OBD2 scanner shows no faults.
Local garage reckons it's the BCU and has experience of Minis...
First Check you engine bay fuse box if these get wet they can cause problems
Also if you BCU was damp you need to disconnect the connectors and clean the pins and plugs first. You can get a switch cleaner lubricant from maplin or halfords
Just remember to disconnect your battery first neg then poss then to reconnect poss then neg.
If you BCU is getting wet you must find out where the water is getting in
It could be a bad door seal, window not raising when you close your door, bad grommet on the wiring loom or a deadly sealed windscreen.
You obd scanner will not go down to dealer level if you want to get right in there get you self a obd cable and a copy of dis v57 from ebay it's about £25 to £30
So, if I disconnect the battery as you describe, is it ok to take the BCU/BC1 out of the car? Won't it need coding or something when it goes back in?
I'll get some contacts cleaner (solvent presumably?) tomorrow. Would brake cleaner do the same job?
I can't find any trace of any water ingress, apart from ingress into the boot which is under the tool tray. I actually think that may be coming in from underneath though? I've taken 2 gromets out of that so that if water comes in, it can get back out easily enough.
Only had the car a few months and stuff like this is ruining it for me.
No problem brake cleaner is a bit strong really, a good switch or circuit board cleaner is really what you need, when you unplug the BCU just have a good look at the connectors make shore there is no corrosion on them. If they are clean you could even use something like gt85 or wd40 which you can get from halfords
If you disconnect the battery it will not need recoding you will only have to set the time on your clock. When you reconnect the battery you may find you onboard temp display counts down, don't worry about that it will sort it's self out
Just a thought do you know if your car has or had a cd changer in the boot
There has been BCU faults caused by damp cd changer plugs in the boot, if you are un shore about the cd in the boot, pop open the right hand access panel where you would get to change your rear light bulbs. If you look at the bottom of the access hole you will see a loom, if there is a couple of connector there make shore there clean bad dry. They may be tucked under the boot floor carpet so have a good look round just Incase
Hi, no cd changer in the boot, but on the drivers' side there is a 'spare' loom which I assume would be where the 6-CD player would connect to. It's taped down pretty well, doesn't look like it's ever been used. I'll get a bit of WD40 on i and dry it out.
For info, up front I've connected an 'aux-in' socket to the back of the radio - not sure if that would have an effect surely?
Many thanks for helping. I really appreciate it. If you were local I'd buy you a beer.
If you look at post 2 I put some places to check, get the trusted hose pipe out with someone in side see if you can spot it.
Or it could be a badly adjusted window a quick way to check this is stick masking tape along the top edge and forward edge of the window close the door, make shore the window raises then draw along the edges of the black trims open the door.
You should have a line 5mm along the top edge of the window and about 3mm down the front of the window.
Marque has guided you well on all the usual checks for your symptons. If the signals from the various modules around the car get confused or corrupted on the Mini's modern bus network wiring system either by moisture, corroded connections, bad earths, low battery power or a faulty module, all sorts of strange electrical glitches can occur.....finding the cause is not always easy and is often a process of elimination.
If the BCU has possibly gone faulty it may be worth contacting BBA-Reman in Kent as they can check your BCU out and then repair your own if necessary (via courier parcel) which means it won't need re-coding to the car by a Dealer. (A new or secondhand unit would need coding. New BCU is expensive and a used BCU is not always easy to get coded by some Mini dealers).
BBA-Reman: MiniCooperBodyCtrl MiniCooperBodyCtrl
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Ok, another odd symptom. Came home today to find rear wiper vertically up - not 'parked' horizontally. It's been raining heavily here...
BC1 seems bone dry, but water is coming in to the boot/trunk. I took the panels off the hatch and found a water leak coming in via the sides of the glass on the hatch - and it's pouring in directly onto the module pictured below. It was covered in dried water stains so I've cleaned it up with electrical cleaner and let it dry properly.
What is this, and what does it do? If this got wet, could it cause random faults as I've described earlier in this thread?
Here's the photo:
I've sealed up the sides of the glass with some mastik so once it cures fully I guess I'll have got rid of over 90% of the leak.
Anyway, it seems that faults seem to occur after heavy rain. Can't find any sight of rain coming in anywhere other than the boot/trunk.
It's the antenna amp item 4 on the link
if this is getting wet this may also be adding to your problems good find:-) most things send signals back to the BCU. so it's possible it's causing the BCU to go cranky. But sounds like you have a couple of faults causing a common fault.
If you are getting water in check your third brake light and the seal around the rear wiper spindle, rear boot seal is in good condition and rear spoiler is not letting water in, also give you rear washer a squirt to make shore the pipes are good in there to, and also check the rubber trunking between the car body and boot lid is ok.
Also check the panel gaps to make shore the boot lid is shutting correctly
If I am trying to find leaks I normally dry everything mask up with duct tape and get the hose on it and remove bit by bit
3rd brake light and the chrome panel both seem ok.
Using the tried and tested hospipe method(!), found that when water was introduced onto the gap between rear hatch window and side windows (particularly drivers (UK) side, water would pour directly onto that antenna unit. I've used some mastik to fill that gap right up to the top, both sides.
So, I'm pretty sure I've found the source of the leak into the tool kit under the boot floor.
I checked the connections on the loom that go up to the brake light and antenna, and they all seemed dry, and corrosion free. So the leak is presumably at that waist height.
I also took the panels off on the sills - again, the BC1 (drivers side uk) and fuse box (passenger side uk) are dry. I shoved my hand under the carpet as far as I could and it's all good.
One question - the car is on it's original battery - it cranks the engine ok, and when running the alternator's pumping out a healthy 14.5 (+/-0.1) volts.
But, as the symptoms only occur with engine off, could a slowly decaying battery be the cause? I've read elsewhere that it could be the cause - but if a battery wasn't up to scratch, it surely wouldn't crank the car over as quick as it does?
Many thanks for the support - it's appreciated, as always.
If it's the original battery they normally only last 4-5 years so sounds like it's had a good life :-)
I have seen it where they cause all kinds of problem, these minis are very fragile when it comes to voltage and current.
Another thing that can cause funny faults is the power steering pump, you can disconnect the pump electrically just to test this.
My advice buy the proper one from mini as there are a few types then you know it's the right one for shore
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