Body Control Module

[Naulochus]

Hi   New to the forum and wondered whether anyone could offer some advice.

 

I got a 2001 Fabia 1.4 last year (first post-driving test car).  It's mostly run fine, but recently I had noticed that the car wasn't starting as promptly as it used to (engine would turn over but not 'catch' immediately), and I got in one morning to find the battery completely dead.  After having it in the garage for some time - they seem to have figured out that it's a problem with the body control module.  If I remove fuse 43 overnight, the car runs fine.  If I leave it in, then this seems to intermittently drain the battery.

 

The garage have quoted me £300-£400 for the new part.  I saw some very cheap ones on eBay, but they did say that I need to be careful, and want to avoid buying one with a similar fault, having it fitted and running into similar problems again. 

 

Has anyone else had similar problems, and could anyone offer me advice on where to go from here?

[Breezy_Pete]

I'll be interested to hear how this goes for you, as I had a similar thing a while ago while trying to help a friend with her car. Fuse 43 was using 150mA for a while even after the car was locked up, though it did drop to 30-odd mA within an hour, but that was still higher than expected.  Never got to the bottom of it unfortunately, as I had limited access to the car.  Just succeeded in confusing myself by the different fusing arrangements on Fabia and Polo for what I'd assumed was the same item, basically.

 

I've not heard about any common failures within these units, but I'm sure someone out there has some knowledge.

 

They don't look hard to swap out DIY, so I would be tempted to buy an ebay one with exactly the same part number as yours, and same year, and use one of the guides on here for something like brake pedal switch replacement, to remove lower dashboard trim get access to the module, and give it a try. 

[sepulchrave]

I suspect the battery is 'tired' and short trips have flattened it. Take the battery off and fully recharge it.

The likelihood of the comfort/convenience module being faulty is almost zero but it's a good money-spinner for the garage.

A more likely explanation is that your glove box light is not going off and possibly also the boot courtesy light, remove the parcel shelf and lock the car up as normal to test the boot light and simply remove the bulb from the glove box light since these always fail and cannot easily be tested.

[Tech1e]

Are the talking about the comfort/central door locking module or the central electrics control module? Technically your car doesn't have a BCM.

[Naulochus]

Thanks so much for all the replies:

 

Wino - Your friend's problem sounds identical to mine.  I'm tempted to get one of the cheaper ones from ebay and - if it doesn't work, chalk it up to experience and get the more expensive one.

 

sepulchrave - Your idea about short journeys flattening it was what the garage initially suspected too.  It was fully recharged by them in the afternoon, and then absolutely dead by the next morning.  Likewise, the glove compartment light and boot light were both checked.

 

Tech1e - You're right, it's the central electrics control module.

[Breezy_Pete]

Don't suppose you're geographically close-ish to me? I'd happily help you investigate this further, or assist with swapping in another module, if you happen to be near.

 

The module contains most of the relays that would traditionally have been unpluggable/replaceable on the relay 'panel', so it may be something to do with one of those.

 

One avenue of investigation might be to selectively/sequentially unplug the input/output connectors from the module, whilst watching the current through fuse 43 socket. That might help narrow down where the current is going, or what's causing it to be higher than it should be.

 

Do you have a multimeter that you could use to measure currents?

[Tech1e]

I have a spare 6Q1 central electrics module should you need one.

[poiuytre111]

I know there are 3 variants of the central electrics module and that it looks a bit tricky to get to but does it require significant programming (VCDS ?)  - I assume it would.

I looked into this a while back when thinking of retro fitting cruise but I would expect central locking, elect seat heating etc all to be configurable.

[KeithCheetham]

I know there are 3 variants of the central electrics module and that it looks a bit tricky to get to but does it require significant programming (VCDS ?)  - I assume it would.

I looked into this a while back when thinking of retro fitting cruise but I would expect central locking, elect seat heating etc all to be configurable.

Not sure if this is applicable, interesting reading if not:-

http://www.team-bhp.com/forum/diy-do-yourself/169586-vw-polo-diy-upgrading-bcm-body-control-module.html

Edited 5 September, 2016 by KeithCheetham

[Naulochus]

Wino - thank-you very much, that's a kind offer - but I'm located up in Scotland, so maybe a bit too far

 

One avenue of investigation might be to selectively/sequentially unplug the input/output connectors from the module, whilst watching the current through fuse 43 socket. That might help narrow down where the current is going, or what's causing it to be higher than it should be.

 

Do you have a multimeter that you could use to measure currents?

 

 

I'm not anywhere near technically-minded or proficient enough for this.  It was never an issue before I had a car, but it is starting to frustrate me now when things go wrong and I have no idea how/why it's happening, let alone how to fix it.  I'm trying to learn more as I go

 

Tech1e - that would be fantastic.  I can't send you any pms as a new member - but would you maybe send me a message with details of price, etc? I understand, too, that the part numbers have to match?  If I have details, then I can get in touch with the garage about fitting it.

[Naulochus]

Just wanted to say thank-you so much to Tech1e - the garage fitted the part you sent and the car is running perfectly. :clap:

[Breezy_Pete]

Nice one Tech1e.

 

Don't suppose you've still got your old unit Naulochus? I wouldn't mind doing a post-mortem on it if you'd be willing to send it to me at my cost.