Checked the plugs for corrosion to your BCOM in the driver's footwell?

 

Thanks for the reply. No, but I'll certainly ask the garage to check. Thanks for the suggestion.

The windscreen washer pump was replaced last year. I think that's in a similar location.

 

Have a search about it, a known issue is washer fluid tracking up the wires from the pump and causing corrosion to the plug and socket in the central fusebox module (BCOM). It's safe enough to simply unplug the connector (I think it's the top left blue one, but search and check) and check the pins are clean and not blue/green or missing, and of course no water or liquid.

 

Great advice. I'm out of my depth already with the fixes I've tried and it was me that replaced the washer pump. I hope I haven't screwed myself now with a big bill if I haven't done it properly.

I'll mention your advice to the garage. Thanks again.

 

The consequence of all this is that nothing temperature related will work. Fans, demisters, heated seats etc.. It’s an absolute nightmare because the windows mist up and I have to keep the windows down to ventilate the car. I’ve got a fan on order from Amazon until I can get this resolved.

I don't see any relationship for heated seats to the external temp sensor, nor should it be able to stop demisters etc working ( though it may prevent automatic select of demist/defrost on cold mornings )

I imagine cutlea01 is spot on about it being BCM ( Body Control Module - also know as CJB, and FSJB ) related, on the saloon the washer pump wires are on the same connector as climate control and I've heard of a few cases where they have been corroded to the point the pins break off the BCM!

I suppose the other thing is is your battery alright, energy management can shut systems down when the battery is failing.

 

My external temp was showing as 2 dashes -- which meant the heater and heated screens wouldn't work, I also had the passenger DRL stay on after locking the car, it turned out to be corrosion in the CJB even though I replaced had replaced the washer pump 4 or 5 years back to stop this happening.
First thing I did was to put a break in the wiring from the washer pump to stop any further wicking of water on the inside of the cable, I cut the wires near the pump connector, soldered the ends (Moisture can't get past the solder) then crimped bullet connectors for the joins, heat shrinked covering over them and also taped them all up. I changed the washer pump again at the same time, this time for a £10 pump off ebay (Last pump was genuine Jaguar).

The DRL and Heater pins broke off in the connector and my CJB was corrupted even though I left the car 30 mins before disconnecting the battery. You can pull the plug to check for corrosion (Top left green connector) and if you have corrosion you will see it mostly in the bottom left of the connector.

I was lucky enough to have Mojo88 come out and replace the CJB, he is very quick and really knows his stuff. Somehow the ticking relay I always used to get from turning on the rear windscreen heater also got fixed in the process which is interesting as the fix for this is suposed to be RJB replacement.

 

Thanks a lot for the replies. The garage is going to take a look. It hopefully solves the mystery.

I've been told it's now a staggering cost to replace the BCM. The cost of the part has gone up 3x in the last year to almost £2,000 +VAT. Then there will be labour. Obviously, I'll shop about if this is the case.

Is there any prospect something could be salvaged from the existing BCM, given the fault is intermittent and clearly hasn't completely died (yet)?

I'm not sure the expense of the repair can be justified with the current value of this car.

 

Yes, there's members here who can reprogram your existing BCM if it's got corrupt files, but depending if it is physically damaged, though corroded pins can also be fixed with the deft use of a soldering iron and a bit of dexterity. Don't just assume your garage must replace the unit if they say it is damaged. It is also possible to reuse a foreign BCM but it needs an expert to "virginalise" it and then flash it to your car.

 

That's great to hear. I'm quite literally leaving for the garage now. Thanks again for your help .

 

I've definitely been through the range of emotions on this one.

The bad news is the BCM is now even more expensive. It's well over £2k + VAT + labour. There is also a supply problem.

The good news is the garage was able to clean up the pins (undamaged) and apply some electrical spray. Everything is working again.

For anyone reading this in the future with a similar problem, the corrosion related to this climate fault doesn't appear to have been caused by the screen washer pump. I'd already replaced mine a year ago because it packed up. I had been worried my amateur mechanics had caused the problem.

However, the CJB pins affected by corrosion aren't those normally associated with the screen washer problem. The corrosion appeared to be of a historical nature and there weren't any current signs of liquid ingress in the CJB.

I was kicking myself for not replacing this car sooner. It's my first Jag and I love it, but I'm now unsure about another. The electrical gremlins on these cars are a bit too much for my liking. I think it's a poor design to have the BCM housed so low and making it vulnerable to water ingress. As for JLR, the cost of the BCM just feels like a racket and the screen wash pump should have been a recall.

I really appreciate the help getting to the bottom of the fault. This is a great forum.

 

No prizes for guessing why I am back! I now need a longer-term solution because the problem has reoccurred.

The corrosion on the BCM didn't look recent when the fault was first discovered, so I'm guessing the garage didn't do a good enough job of cleaning it up and / or the electrical spray is no longer having an effect.

The car needs to be sold, but it wouldn't sit well with my conscience to sell it in the current state. It was a nightmare identifying this problem in the first place and someone else may have to endure the same. @cutlea01 you were kind enough to mention some people that may be interested in the business to clean up the corrosion in the BCM. Do you know how I might go about contacting them?

On a side note, the weather is hotting up and I'd like a temporary fix whilst I wait for a proper repair and I don't have any fans or ac. Is the BCM easy to remove and apply electrical spray? I've looked on YouTube. I don't really want to return to my garage. They already fitted a new temperature censor when it was unnecessary and I'm well aware that you can't be too rough with these BCMs.

Thanks for your help.

 

...

The corrosion on the BCM didn't look recent when the fault was first discovered, so I'm guessing the garage didn't do a good enough job of cleaning it up and / or the electrical spray is no longer having an effect.

...

On a side note, the weather is hotting up and I'd like a temporary fix whilst I wait for a proper repair and I don't have any fans or ac. Is the BCM easy to remove and apply electrical spray? I've looked on YouTube. I don't really want to return to my garage. They already fitted a new temperature censor when it was unnecessary and I'm well aware that you can't be too rough with these BCMs.

Thanks for your help.

To remove the BCM you need to
1. Move the driver seat back as far as it goes
2. Disconnect the negative leads from both batteries ( best follow - https://www.jaginfo.org/threads/shout-for-help.114952/#post-2925271 but wait 33 mins instead of 20 if it's a saloon rather than sportbrake )
3. Pry the kickplate up across the right hand front doorway ( use a trim removal tool pushed in over the carpet to near it's center line, to lever it up and work your way along to undo all the clips so as not to bend the stainless steel insert )
4. pull the door seal off from front the front edge of the trim you just removed up as far as the top of the dash.
5. Remove the trim from the end of the dash ( pry it out from the edge nearest the back of the car, then it pulls to towards the rear of the car - it has a plastic pin on the back that goes through the lower trim. )
6. Pry the two clips on the panel at the right side of the footwell out with a trim removal tool, and then remove the panel toward the rear of the car.
7. Remove the "carpet" trim from under the dash for better access ( two clips near the front, and bend it slightly to get it out )
8. unplug as many connectors as possible from the CJB ( they all have clips that need to be squeezed in, and make sure you only pull the connectors not the wires! )
9. Pull the rubber cover back, and remove the nyloc nut holding the main power cable on ( 12Nm ), and remove the cable from the stud on the CJB.
10. Undo the fixing bolt at the bottom of the CJB, and the nut from the top.
11. Pull the CJB off the stud at the top, then you can disconnect any remaining cables that proved too tight in step 8 as you can change it's orientation to get a better angle.

I suggest after cleaning the contacts apply a coating of Nyogel 760G - don't forget you can de-pin the connector on the harness to give you better access to clean those pins too. ( see https://static.nhtsa.gov/odi/tsbs/2015/SB-10096454-1020.pdf )

Mototronics may be worth a look ( I've not used them so let us know how it goes it you choose to use their service. )

Jaguar XF Central Junction Box Water Damage Repair Service FCJB BCM – Motortronics Car Electronic Specialists

motortronics.co.uk

Though at least one member has replaced their own pins, this thread looks interersting https://www.jaginfo.org/posts/2990447/ but I'm not sure if @stabio has found the time to do his youtube video yet.

I've seen other posts where folk have soldered a bypass wire to the back of the board, and fed it out a hole drilled in the casing to bypass badly corroded/broken off pins.

With luck you might not have broken pins, please let us know how you get on.

 

Where are you located as someone may be able to recommend a good indi in your area with experience of repairing the CJB. In Derby, there is Elite and Performance Jaguar and when I mentioned the CJB issue they seemed to be able to reuse or repair bad units, so if close by it may be worth giving them a call. I have a prefacelift so not needed to deal with this issue so far.

 

Thanks AntF. Derby is an option. Home counties would be better for me. I'll do some digging. My garage is a Jaguar specialist, and they are generally very good, but this issue seems a bit alien to them - not their knowledge of it, but rather their understanding of a remedy without a replacement.

 

E&E Motors in MK may be able to help, and a bit closer.

 

Perhaps the screenwash pump has been replaced twice, climate system wiring is on the same connector as the washer pump and often damaged when the screenwash makes it to the CJB. I suppose it's possible it's had a leaky windsceen or similar but they you'd expect the damage to be much more widespread.
BTW if you're wondering why I suggested Nyogel 760G, it's because the pins will corrode again quite quickly, and not make particularly great contact due to the plating on them being damaged/missing where they have been previously corroded.

 

Thanks Phil - makes sense to someone like me with very limited technical knowledge. The Nyogel 760g not only prevents further corrosion, but it will presumably also help make the circuit connection if the pins have been damaged by the corrosion.

I think I'm going to go with this option in the first instance and insist the garage uses Nyogel. (BTW, everything is working again now without any further action.)

 

My Jag specialist has refused to do the work. I understand their concern. They are worried about the pins breaking whilst opening the CJB. They applied the electric spray last time because they'd already opened the CJB to inspect it.

I'll try E&E in MK, who were recommended earlier. I'd really appreciate any other suggestions.

The most frequently occurring result with web searches is Jaguar XF Central Junction Box Water Damage Repair Service FCJB BCM – Motortronics Car Electronic Specialists Does anybody have experience of them?

 

I'm getting quite a list of places willing to do a refurb or fit a second hand unit. I'll post it up on here when it's complete.

The refurb option does seem to invariably require removing the CJB and posting it, so I might need to go back to the very kind instructions from @xf_phil.

 

Yeah, while motortronics.co.uk are the only ones I've seen with a nice clear explanation of how they'd fix a connector, I'm not sure I'd risk sending it there, as as far as I can see they don't have an address on their website anywhere!
A few others idea of repair, is only reflash for corruption on battery disconnect.

Having said that re getting a garage to do it ( and probably send it off somewhere to repair ), vs removing it yourself - it's worth enquiring if they're gonna charge you for storage for the time it sits at there garage, and what they charge for the actual CJB repair ( presumably will be add their markup to whatever the fee if from whoever they use )

If it were me, I'd remove the trims and take a look at the part number on it, if it's DX23-14B476-AG then worst comes to worst you can probably pick a replacement up from ebay for ~£500, and get your current junction box cloned to it, and if you're luck you get away with just needing a tube of Nyogel 760G.

If it's DX23-14B476-AH then a replacement is going to be a lot harder to come by, and there may be issues with cloning it too.

When I cleaned mine up I used these de-pin tools ( certainly not the cheapest option but come with tiny diamond files which might come in handy if corrosion is really bad, but I didn't use them, I did use one of the depin tools to scrape out the inside of the connector on the harness after de-pining too. )

Maerd 87pcs Terminal Extractor Removal Tool Kit, Terminal Ejector Kit Depinning Tool Wire Connector Pin Release Set, Come with Automotive Circuit Tester & Terminal Cleaner Set & Trim Removal Tool : Amazon.co.uk: DIY & Tools

Maerd 87pcs Terminal Extractor Removal Tool Kit, Terminal Ejector Kit Depinning Tool Wire Connector Pin Release Set, Come with Automotive Circuit Tester & Terminal Cleaner Set & Trim Removal Tool : Amazon.co.uk: DIY & Tools

www.amazon.co.uk

Widest trim tool from this set is nice for prying up the trim across the doorway.

Amazon.co.uk

 

Great stuff xf_phil. I'm sure novices like me will find your suggestions and instructions very useful.

I was too nervous and I'm still wondering whether being too adventurous with my amateur mechanics got me into this trouble in the first place (when I replaced the washer pump).

I had arranged to get a mechanic out next to one repair place (twice in one day) for a same day repair / refurb. I may still go down that route, but it was getting expensive. I've now found a well established repair centre that's going to do the whole thing.

I don't want to post the route I've taken until the work's done. I'm still a bit undecided and I don't want to offend anyone I won't be using.

I will say there seem to be 3 obvious repair places from Google searches. London, Kent and Wales. Prices are about £250 - £300. Only one of them was really helpful and responsive. Two of them clearly have a lot of knowledge and experience for XFs.

Then there are the seemingly very reputable independent Jaguar specialists. In my small sample, they are not interested in repairs. However, they will fit a reman CJB for about £700 - £800.

I've heard various references to reprogramming from them, but they also say the chances are less than 5% in their experience. (Costs were quoted as anything from another £150 to £300.) Only one of the repair shops mentioned taking precautions to prevent this. They said disconnecting the battery was an option when I challenged them, but suggested they'd let the car hibernate for 30mins with the door open before removing the CJB. It made me a little nervous after what I'd read on here about disconnecting the battery.

Anyway, thanks a million for your help. I plan to share back my experience when it's done. If anyone is facing the same problem and would like the information sooner (or I forget), they can quote my post and I'll see the alert in my email.

 

Hello - I'd like to ask one last bit of advice. was very close to being able to sort out a mobile fitting for a replacement (reman) with MoJo88, but he's gone on holiday and I don't know when he'll be back. I've got to a point where I need to get it done, so I've bitten the bullet myself and accessed the BCM to have it sent for repair.

I'll attach a photo below. Can I check on the steps?

1. leave the car idle with everything switched off and the door open for at least 30mins

2. disconnect battery

3. remove the BCM

I'd been led to believe there were 2 bolts fastening the BCM, but I can only see 1? Also, is it 4 plugs that need to be disconnected? (2 grey on the left, 1 orange and 1 green on the right.)

 

Okay, I said I wasn't much of a mechanic!

I've found the blue plug (actually in the photo!) on the left and the 2 grey plugs covered by the upholstery at the bottom. I make that 3 on the left, 2 on the right and 2 at the bottom.

I've also found the two black (plastic?) nuts or bolts in the recess at the top and bottom of the BCM. In addition to the live nut in the photo.

Is this everything?

Any ideas how to get at the two black nuts fastening the BCM. They are quite a way back. I'm guessing some sort of ratchet screwdriver? They look like they might be 10mm.

I'd really appreciate any help. Thanks.

 

At the top there should be that one nut attaching the cable, and just above it ( other side of a plastic ridge ) another nut holding the BCM in place.
Have a look at the last pic in my post https://www.jaginfo.org/posts/2843843/ ( it' of the rear BCMB, but they're pretty much the same ) you can see the nut just above the one for the cable ( hidden behind that rubber cover )

It should be pretty easy to get the nut holding the top and bolt at the bottom with deep reach sockets like https://www.amazon.co.uk/gp/product/B001URI66M and a small ratchet like https://www.amazon.co.uk/Draper-16427-Tooth-Reversible-Ratchet/dp/B071KKKY4X a short extension e.g. https://www.amazon.co.uk/Draper-16716-Square-Wobble-Extension/dp/B074MHYN33 may also be desirable but I think you'll get away with just deep reach sockets.
Ease the carpet back, and feel under the unit, the bolt is in the center, just like the top one.

Be careful not to drop anything behind the carpet or through the hole in the panel above the BCM.

 

Hello - I'd like to ask one last bit of advice. was very close to being able to sort out a mobile fitting for a replacement (reman) with MoJo88, but he's gone on holiday and I don't know when he'll be back. I've got to a point where I need to get it done, so I've bitten the bullet myself and accessed the BCM to have it sent for repair.

I'll attach a photo below. Can I check on the steps?

1. leave the car idle with everything switched off and the door open for at least 30mins

Engine off.
Open and close the drivers door.
Ensure all doors are closed.
Open the boot/tailgate.
Put keys out of range.
Wait 33 mins ( or is it 20 - only listed under sportbrake , see table in https://www.jaginfo.org/posts/2882777/ and decide for yourself. )

2. disconnect battery

You just need to disconnect the negative cables ( of both batteries )

3. remove the BCM

I'd been led to believe there were 2 bolts fastening the BCM, but I can only see 1? Also, is it 4 plugs that need to be disconnected? (2 grey on the left, 1 orange and 1 green on the right.)

View attachment 202057

Bend the carpet out a bit at the bottom, you'll find there are 3 connectors across the bottom, and a bolt holding the unit in place ( dead center left to right )

 

Thanks @xf_phil. Your advice has been incredibly helpful. I'd already bought a a small ratchet this afternoon. It won't arrive until Friday. I'll let you know how I get on.

Funnily enough, I'm probably now getting dangerously ambitious, but I'm firstly going to try your original suggestion and clean up the pins. I just never thought it would be so easy to get the cover off. I'm only going to apply some WD40 contact cleaner spray https://www.amazon.co.uk/gp/product/B006UCJ5WQ/. I've also ordered some dielectric grease https://www.amazon.co.uk/gp/product/B000AL2RI2. Not NyoGel 760g as you recommended. It's a bit of a shot to nothing and the NyoGel was expensive. I think I'll place a small drop inside the plug socket and see if it will apply itself to the pin. I know I'll snap the pins if I try and clean them up with anything else.

If it ends in disaster, I will just send it off to be repaired, which was the original plan anyway.

You've been a great help. Thanks so much. Once everything is done, I will post up my list of 5-7 places that are now doing repairs for these BCMs. It seems this problem has created its own industry. I can say now that I wouldn't recommend anybody uses Motortronics (discussed on the previous page). The guy was a complete let down and cost me at least 3 weeks of delays before I gave up on him. Booked it in for a repair and then he didn't answer his phone because he said was always too busy to speak and refused to call back.

 

It's a bit of a shot to nothing and the NyoGel was expensive.

Maybe you didn't find these listings, an extra £6.10, or £8.20 for 2.5 times as much.

Amazon.co.uk

Amazon.co.uk

Feel free to use either of course it's your CJB

BTW for my pins, I cut a cotton bud through the stem at a bit of an angle, and used the cut end to very gently scrape corrosion from the CJB pins in my CJB plug. Also don't forget to clean the socket ( on the end of the wiring hardness ) too. I don't think you can realistically clean the socket without depinning the pins in question to get better access to them - but you will find that cable has enough slack to reach to the doorway which will make things considerably easier.

 

Not WD40. That's not an electrical contact cleaner spray. Buy some proper electrical contact cleaner.

 

Thanks. It's not the normal WD40. Hopefully, this will be okay? It seemed very popular on Amazon.

 

Yep, that'll do very nicely. I forget WD40 is now trying hard to be a brand rather than a single (and rather dubious) product.

 

white vinegar Is good to remove corrosion too, just soak the plug for a least 15mis but remember to soak in water to rinse, then a apply a good electrical contact cleaner.

 

It's the big day for me

Just wondering if anybody has an opinion about how to apply the dielectric grease after I've cleaned up the connectors?

I'm terrified of breaking the pins, so my plan is to remove the connecting plug and apply the grease with drops into the female sockets on the plug, with the hope it will apply itself when re-inserted.

 

It's the big day for me

Just wondering if anybody has an opinion about how to apply the dielectric grease after I've cleaned up the connectors?

I'm terrified of breaking the pins, so my plan is to remove the connecting plug and apply the grease with drops into the female sockets on the plug, with the hope it will apply itself when re-inserted.

Yip it’ll find it’s way in if you coat the pins, you don‘t want a hell of a lot in there anyway.

 

Actually, the pins looked pretty strong in the photo I managed to take after applying the spray. Not sure how much grease I was able to apply - I probably got it 1-2mm deep in each socket and then put the plug back in. I've now got a few regrets about not taking the CJB out and giving it some more thorough maintenance. I can always do it again now I know what I'm doing.

Overall, it seems a success. It's been working for the past few days, so annoyingly I can't yet notice any difference. Time will tell. The car did a few strange things when the battery reconnected - messages on the dash. It seems to have settled down, but the doors bleep after locking. I can live with that.

Thanks for all your help. It's really appreciated. I never thought I'd be able to do something like this myself.

Next post will be all the repair / refit people I managed to locate via the web. Hope others will find it useful if they end up in the same predicament and can't do a repair on their own.

 

Not sure how to tag on here, so let me add a few keywords for anybody searching:

BCM / CJB / corrosion / water damage / pins / repair

I found there were two decisions:
1. Repair or reman - rough rule of thumb, reman costs at least 2x repair
2. Logistics - remove yourself and post / home visit / take to mechanic (not many options for the latter)

The risk with repair is it may not be possible and could require re-programming (a lot of extra £). Reman isn't risk free, but I suppose it wouldn't hurt to ask for a guarantee.

Just my 2c, but my top 4, based on knowledge, experience and somewhat on cost.

Remanx

• seem to know this problem inside out and they do many repairs (not just Jags)
• I think they do repair and reman - cost of repair is £270
• postal service, but if you ask nicely they might allow you to drop-off in the morning and collect on the same day (in Rochester, allow most of the day and they won't remove / fit the CJB)
• ask for Tommy, great guy - really can't fault them in any way whatsoever

Mojo88 from jaginfo.org

• good knowledge and experience
• we didn't get very far because he went on holiday
• reman only, fitted
• didn't get as far as cost and that's for Mojo88 to advertise
• will visit you at home if he covers your area
• very helpful, responds to DMs on here

Pelican Diagnostics

• good knowledge and experience
• repair and reman - cost of repair is £179
• helpful and responsive
• only offers a postal service (Sleaford)

jlr.tech (web address)

• seemed very familiar with the problem
• repair £300 and reman £600
• seemed really helpful and accommodating
• posted or fitted (Huntingdon)

Others, no particular criticism, but didn't work for me and / or them

• Tom Lenthall, Ascot - reman only for £700 to £800
• Mervyn Ashton, Harrogate - didn't get as far as cost - replaces the pins with wiring
• Plug and Play ECUs, Blackburn (eBay) - pretty sure they know what they're doing and have experience - wouldn't quote and wanted a £50 test charge
• Jalnaz0 eBay - seemed to know his stuff, but the conversation stopped (nonetheless, encouraging in quite a few respects)

It's obviously just my personal opinion, but I wouldn't go anywhere near:

• Motortronics - said he'd do it the following week and then just completely ghosted me. Never picked up calls, occasionally responded to messages saying he was busy and would call back - never did. A complete joker - cost me 2-3 weeks.
• Omega7819 eBay - ridiculous process of needing to pay for his service on eBay (£250 TBC) and then he'll be willing to tell you the exact cost, how long it will take, when he has availability. If anything bothers you about buying on eBay, this should ring some alarm bells. He did redeem himself a bit when I later had a problem with SDD immobilisation, but his prices were still very high compared to what I found elsewhere.

Hope this helps someone unfortunate enough to be in this situation. I'd say you won't go far wrong with Remanx or Mojo88, depending on your needs and location.