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bebechoon



Member Since: 22 Apr 2014
Location: In ze middle of Frainsch nul part
Posts: 452

France 
BCM/BCU unit replacement ..How-to..

The following �How-to� is intended for DIY owners like me who have limited mechanical and technical knowledge. I defer humbly to our more experienced members for whom this is probably routine stuff!

For some time I had been having intermittent issues with rear door and tailgate unlocking combined with heavy steering on my 2005 Td6 Fatty. This problem (documented on this forum) can be caused by a faulty BCM/BCU (Body Control Module/Unit). I was daunted by the prospect of replacing my unit, firstly because I am no more than a reasonably-competent DIYer with no mechanical training or experience, secondly because of the cost, and lastly because I have no garage and working outside is no fun � it is often too hot down here to work in the open and, on the rare days when it�s not sunny, it�s often raining!

The new unit requires programming to the car otherwise, it seems, many features will not work (see http://www.fullfatrr.com/forum/topic33390.html, in particular Mattstevenson2005�s post d. 25/08/2015). This was what was putting me off as programming would normally have to be done at a Stealers or Indy, and I have no confidence in any near where I live. However, those wonderful chaps at GAPDiagnostics have now developed a module for the IIDTool which does the programming. Axle � who had already done it � convinced me it was really simple, so I decided to bite the bullet.

Having contacted GAP, they promised they could indeed make a special build available for my model/year to download to my IIDTool. They were true to their word!
So, I ordered a new BCM/BCU from Duckworth Parts (site sponsor).
I now had no more excuses �

In theory, replacement of the BCM is simple: remove the passenger seat, unplug the old unit and pull it out, put in the new, plug it in, run the IIDTool module � and bingo!

Unfortunately, for me, things did not go quite that smoothly and I had a few issues: silly things where if you�re in the know, it�s easy; if you don�t know � So I decided to do this �how-to� in the hope it will help other DIYers avoid the silly mistakes I made.

Down to work:
Note: My Fatty is LHD. Please bear this in mind if the images do not correspond 100% with RHD cars �

Step 1 was to download the special build provided, on request, by GAP (this replaces the standard analysis module in the IIDTool so afterwards, once you�ve finished, you need to re-download the standard module):
- Start the updater software then connect the IIDTool to the computer
- Click on Find device
- Select Special buildnnnn� (provided specially by Gap)
- Click on Program Firmware
Wait until completion, then disconnect.

Next, in the car:
Step 2 was to disconnect and remove the old BCM/BCU and replace with the new unit. RAVE suggests the front passenger seat has to be removed but I found that simply unbolting it and tilting the whole seat backwards gave plenty enough room to work:
- Move seat to fully-back position and undo the 2 seat runner front retaining nuts (16 mm). Now move the seat fully forwards and remove the 2 seat runner rear retaining bolts (also 16 mm).
- Disconnect the battery (see Wiki) and wait 20 minutes or so for all systems to shut down
- Tilt the whole seat backwards, taking care not to stretch the cable connected to the underside of the seat.
- Remove the black plastic BCM/BCU cover plate (2 �turnbuckle� screws you turn through 90�):


- Unclip the 3 multi-plug connectors:



This sounds easy but the locking mechanisms had me stumped and I made a complete mess of it!
This is how to unclip them:

Firstly, the big black connector: the �locking cover� on this has to be pushed to one side so that the lugs slide down the grooves:



If necessary, insert a flat-bladed screwdriver where shown in the pic below and, whilst continuing to pull outwards and to the side, gently �help� the plug out with the screwdriver:


The lugs should slide further along down the grooves, releasing the plug.

Secondly, the 2 smaller connectors: there is a white clip locking mechanism which, when pushed to the side, �ejects� the plug (conversely the other direction �pulls� the plug firmly into the socket and locks it in place):


However, there is a clip locking pin on the �top� of the connector (i.e. facing the rear of the vehicle) which first needs to be depressed to allow the clip to move to one side:


As the locking clip is moved to the side around its axis (hidden in the body of the receiving connector), the plug is ejected.

- Push the multiplugs and harnesses out of the way. You should now be able to slide out the old unit.
- Insert the new BCM/BCU and connect the 3 multi-plugs in the reverse order of removal.
Very important: make absolutely sure that the connectors are fully home and secure and that the cable harnesses are positioned so that there is no �pull� on the connectors, otherwise this could result in a poor connection and all sorts of electrical anomalies (as I know to my cost!).
- Replace the plastic cover and secure with the 2 �turnbuckle� screws.
- Reconnect the battery
- Refit the seat

Step 3 Connect the IIDTool and select Menu --> Service/Test --> BPM-Body Processor --> Renew ECU When the programming has finished, go back up through the menu to be able to exit the IIDTool, then disconnect.

Step 4 Now you simply need to do the usual steering full-side-to-side after a battery disconnect, and perhaps re-programme any tweaks to the CCF you had previously made.

And that�s it. I�m very pleased to say that my rear door unlocking and heavy steering seem to be a thing of the past, as does an intermittent rear parking sensor problem � although I don�t know if that�s just a coincidence or because of the new BCM/BCU � (Seeing as the BCM/BCU has a say in almost every electrical function on the car, I rather hope it�s not just a coincidence!)

I really cannot end this without giving a special mention to the excellent service and support received from two sources:
1. The Gap Diagnostics team. Within the space of 2 days, they made available to me the special build module which automatically programmed the BCM/BCU for my model and year via my (non-BT) IIDTool. They (Pat) also patiently responded to dozens of E's I sent them as I was having all sorts of electrical anomalies (caused by the connectors not being seated properly!). These guys seem to have praise heaped on them on this forum whenever anyone has had dealings with them. What more can you say about them? Their after-sales (and technical support) service is nothing short of excellent.
For anybody hesitating about buying a IIDTool, my advice is: stop hesitating, buy one, and it could pay for itself very quickly.
2. Dan at Duckworth Parts (site sponsor). I ordered my BCM/BCU on the Tuesday and it was delivered to me in France by midday on the Friday. Again, really great service, together with very competitive prices; buying from Dan gave me a saving of 20-30% compared with many of the usual parts suppliers. Highly recommended.

Lastly, forum members Axle and Mattstevenson2005 deserve a mention and thanks for their help and pioneering work which encouraged me to do this job myself, thus saving ���� in garage labour costs! It's "bébéchoon", ackcherly, with accents. 'Steve' to my chums.
20 years ownership of Solihull products, ALL GONE NOW, sniff!
Current motor: Suzuki S-Cross 4WD auto, 1.4 petrol. Oh so reliable! 5 years now and no problems. Oh, all right then, a leaking shocker replaced under guarantee.
Previous:
TD6 HSE L322 Auto FF
2.5 TDi 4-door Classic
Disco II
And my 1st Rangie: in 1995, a 2-door VM 2.5 diesel Classic
Not to mention the Lada Niva before those. (I said not to mention it!)

Post #409975 20th Oct 2016 3:33pm
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stan
Site Moderator


Member Since: 13 Jul 2010
Location: a moderate moderated moderator moderating moderately in moderation
Posts: 34871

United Kingdom 

wiki'fied Steve, Thumbs Up ... - .- -.




click link for ,

FORUM WIKI

HOW TO Ǝꓕ∀ꓕOꓤ PICS

workshop manual downloads are in our wiki

.

Post #409983 20th Oct 2016 4:39pm
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bebechoon



Member Since: 22 Apr 2014
Location: In ze middle of Frainsch nul part
Posts: 452

France 

I am indeed honoured Thumbs Up, kind Sir Bow down It's "bébéchoon", ackcherly, with accents. 'Steve' to my chums.
20 years ownership of Solihull products, ALL GONE NOW, sniff!
Current motor: Suzuki S-Cross 4WD auto, 1.4 petrol. Oh so reliable! 5 years now and no problems. Oh, all right then, a leaking shocker replaced under guarantee.
Previous:
TD6 HSE L322 Auto FF
2.5 TDi 4-door Classic
Disco II
And my 1st Rangie: in 1995, a 2-door VM 2.5 diesel Classic
Not to mention the Lada Niva before those. (I said not to mention it!)

Post #409992 20th Oct 2016 5:08pm
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Mulcher



Member Since: 08 Aug 2016
Location: Shropshire
Posts: 238

England 2006 Range Rover Supercharged 4.2 SC V8 Zambezi Silver

Superb procedure Bebechoon. Thanks for going to so much trouble to document it so thoroughly. Bow down 2006MY 4.2 SC
BMW R1250 GSA Rallye TE
Triumph Tiger 1050 (sold)
1979 Pontiac Trans Am (sold)

Post #410001 20th Oct 2016 5:33pm
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tb10



Member Since: 17 Feb 2015
Location: Bromsgrove
Posts: 329

England 2005 Range Rover Vogue 4.4 V8 Tonga Green

Bebechoon,

This is a perfect solution so thanks for posting Thumbs Up Thumbs Up

............but does anyone know if the Faultmate extreme can program the BCM/BCU unit?

regards

John

** EDIT **

It appears the Faultmate will program the BCU...........see you all later Laughing

Post #410017 20th Oct 2016 6:08pm
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thrillcat



Member Since: 04 Jan 2018
Location: Ames, Iowa
Posts: 23

United States 2012 Range Rover HSE 5.0 V8 Santorini Black

This is a great post, and may end up coming in handy.

Can anyone provide a part number for the BCM/BCU for a 2012 5.0L 5000CC V8 GAS DOHC Naturally Aspirated FFRR???

This part is the most mysterious thing I've ever come across! Even the dealership quoted me (I think) the incorrect part. I asked for a part number/price on the Body Control Module/Unit and they gave me a price for a Fuse Box (LR023679).

Post #464775 16th Jan 2018 3:06pm
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Balloonengineer



Member Since: 03 Sep 2017
Location: Kent
Posts: 171

United Kingdom 2012 Range Rover Vogue 4.4 V8 Orkney Grey

Just to add to this thread

I found there is no need to unbolt the seat, just wind the seat to its most forward position, then from the rear footwell pull out the entire BCM (the white VHS size box, not the black plastic surround) with the cables still attached. Its then much, much much easier to remove the connectors

Best wishes
Glen

Post #476663 24th Apr 2018 6:08pm
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Shirval



Member Since: 17 Apr 2017
Location: South East
Posts: 1

United Kingdom 
Thank You. Success changing my BCU

Just a thanks for including such a good level of detail. This gave me confidence to tackle the BCU on my L322 when almost everything BCU related shutdown. Main fault was BCU locked in Transport Mode. I bought the Gap IID BT Tool but although the BCU turn off Transport Mode command routine was accepted and executed the unit would not come out of Transport Mode (no matter how many battery resets). I bought a used BCU on eBay (exact same model BCU). Plugged in - selected renew BCU on Gap tool and everything immediately back up and working (so far as i can tell but main items all working).

Many thanks.

Mark
L322 Overfinch 580S

Post #500527 4th Jan 2019 6:29pm
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Midlifecrisis



Member Since: 04 May 2021
Location: NI
Posts: 7

United Kingdom 

Thanks bebechoon, have to say that your post is one of the most comprehensive I've seen on any forum, I found it after a search to find how to remove the big plug from the bcu - I needed to be a bit more brutal.

The reason I was taking it out is because the passenger side rear window decided to go down and won't go up
The motor is fine and the drivers side window works ok
I disconnected the pressure sensor plug but it doesn't make any difference.
I think the relay on the board is ok, because i connected a bulb across the motor and it lights briefly when the battery is reconnected.
Pretty sure all fingers are pointing at the bcu

Anyone disagree?
Can i just replace it like bebechoon did?
Can I get one from fleebay and use that?
Would it help if I get keys with it?

I have an IID tool

Thanks

Post #594571 18th May 2021 6:59am
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Dolphinboy



Member Since: 07 Dec 2009
Location: Bristol
Posts: 3035

United Kingdom 2011 Range Rover Vogue TDV8 Atacama Sand

don't know what model/year you have but BCU are a straight swap (altho there are different part numbers for different years). Do you find your steering is heavy too? Can also stop the rear pax door unlocking.

Post #594577 18th May 2021 8:03am
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Midlifecrisis



Member Since: 04 May 2021
Location: NI
Posts: 7

United Kingdom 

2002 L322

Apears just to be the rear window at the moment. Also I note that the windows will open on command via the IID tool, but they won't close on command.

Post #594586 18th May 2021 9:37am
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knares



Member Since: 22 Jun 2017
Location: Perth WA
Posts: 698

Australia 2005 Range Rover Vogue 4.4 V8 Zambezi Silver

i find my steering heavy some times and the rear gate plays up some times
i can always lock me car when its parked at home but when its in a car park some where, its like wining a lottery RR 2005 4.4 petrol
Any spelling mistakes are the fault of spellchecker
Previous MG J2, CITROEN light 15 x 2 gone unfortunately
Present MERC 180e, RANGE ROVER L322, JAGUAR XJS, MERC 280SE, MG F, JAGUAR S-Type 6v 2003, jaguar s-type 8v 2004, Ford Cougar

Post #594616 18th May 2021 2:51pm
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bebechoon



Member Since: 22 Apr 2014
Location: In ze middle of Frainsch nul part
Posts: 452

France 

Hi, knares (& others!)
You've described the symptoms I had (see my 2nd para right at the start of this thread) except that, for me, it was pure chance whether the locks would work at home either ...
It seems many peeps have had this intermittent problem and often it has been the BCM at fault. Fitting a new one could be the solution for you, although of course it may well be another problem ...

 It's "bébéchoon", ackcherly, with accents. 'Steve' to my chums.
20 years ownership of Solihull products, ALL GONE NOW, sniff!
Current motor: Suzuki S-Cross 4WD auto, 1.4 petrol. Oh so reliable! 5 years now and no problems. Oh, all right then, a leaking shocker replaced under guarantee.
Previous:
TD6 HSE L322 Auto FF
2.5 TDi 4-door Classic
Disco II
And my 1st Rangie: in 1995, a 2-door VM 2.5 diesel Classic
Not to mention the Lada Niva before those. (I said not to mention it!)

Post #594622 18th May 2021 3:23pm
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Midlifecrisis



Member Since: 04 May 2021
Location: NI
Posts: 7

United Kingdom 

Tried a BCU reset
et voilà

Post #594744 19th May 2021 6:10pm
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CongoBoy



Member Since: 11 Sep 2020
Location: Wiltshire
Posts: 125

South Africa 2005 Range Rover Vogue SE 4.2 SC V8 Java Black

Is the BCU reset a Hard reset, or something different? 2005 FFRR SC Java Black with Overfinch Exhaust (UK)
2008 D3 HSE Stornoway Grey (UK)
2008 D3 HSE Izmir Blue (ZA/Zimbabwe)
1995 D1 300 Tdi (Zimbabwe)

Post #594746 19th May 2021 6:28pm
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