Hi, My daughter's  Mk1 Fabia has been diagnosed with a faulty Body control module by an auto-electrician. The only fault we have is that the RHS indicator is not functioning. The garage has said that replacing the unit will require the data to be backed up, written to a new BCM and then installed. (seems a bit involved for an '06 basic model) Total cost will be £500-£600. So, I'm interested in if they are giving me the correct info.

 

There are plenty of these available on eBay second hand but if the BCM data has to be backed up, then a second-hand unit doesn't seem to be the way to go.

 

I have sent this BCM to ECU Testing Ltd. to diagnose and repair but they came back to me and they do not have the necessary info. for this unit and are returning it at no cost.

 

Any feedback would be appreciated

This page shows the coding process, which will involve VCDS unless the vehicle the secondhand unit comes from has identical equipment, in which case I believe it would be plug and play.

https://workshop-manuals.com/skoda/fabia-mk1/vehicle_electrics/electrical_system/instruments_gci/self-diagnosis_of_the_vehicle_voltage_control_unit_ii/coding_the_vehicle_voltage_control_unit/

 

Well worth eyeballing the wiring coming out of the unit that's in the car right now, I can tell you which connector/wire colour if you like. Another member in a similar situation found an almost-broken wire just near the unit as the ultimate fault cause, rather than anything inside the unit.  I'll find the thread if I can.

I see this is a long-standing problem:
https://www.briskoda.net/forums/topic/440110-right-indicator-not-working-with-engine-running/

 

I think if you fit a secondhand unit with identical part number it'll probably work well enough even if the coding is incorrect, to show whether the indicator fault is really with the unit rather than the rest of the car. May be worth trying as a much cheaper option than the rather offensive £500-600 quoted...

Then if the indicator fault is cured, you could set about coding it to match all the car's features if you can find a local garage or member with VCDS.

Thanks Wino. It's a bit long running for various reasons but chiefly because the indicator started working during the summer and I got it through the MOT. Thought it might have dried something out with the hot weather. Anyway, come mid-October it starts playing up again, then stopped, which allowed Auto-electrician to make diagnosis.

 

If you can point me to the wires that need looking at, I'll have a go. I am competent at most DIY but not car electrics other than using a multi-meter under guidance. I should get the unit back from ECU Ltd. by Friday so could look for a matching one on eBay as a less costly option.

 

If I can find one, will the car run? 

 

Regards Paul

 

VIN: TMBPW46Y874047572

Engine No: BMD 293270

Variant: SCBMDX01

Version: NFM5FM52T089L13S0GGS5

Hi Paul, I believe a helpful fella with username Lightrain posted the wiring info in that other thread I linked, but I can double-check or add info if it's not clear.

 

Yes, I think the car will run with another BCM (technically "Onboard supply control unit", body control module is a later term) even if the coding isn't quite right.

I could be wrong on this though. Later (than Mk1) cars where the Central Convenience control unit is combined with this Onboard supply control unit into a BCM probably need more extensive coding.

 

@Tech1e may be able to confirm?

 

Black/green wire from pin 14 of connector XS6 for right hand side indicators.

If all 3 (front back and wing bulbs) are affected and it is a wiring fault, the fault must be close to the unit as obviously the wiring to the front and side ones diverges from the wiring to the rear indicator, so fault must be nearer than this split.

Much appreciate the assistance.

 

I'll get down and dirty when I get the unit back. Will follow up on previous suggestions if necessary.

Hi Wino, (I'll send this to Lightrain as well) I have replaced original unit in the car. Interestingly, with ignition ON and car NOT RUNNING both indicators work!

 

On XS6,  ignition ON and car NOT RUNNING - Voltage on left output (pin 16) and right output (pin 14) is about 11.85v.

 

With car RUNNING, voltage on pin 16 (LEFT) is 14.2v and ZERO on pin 14 (RIGHT). Left indicator working, right NOT working.

 

Does this indicate a faulty ECU? / Where do I go from here?

 

If so,there are a few on eBay with the same part numbers but come from different cars i.e. 1.9 Fabia TDI, Seat Ibiza 1.2 (our engine size), 9N3 polo, 2006 Polo 1.2

 

Cheers Paul

 

 

 

 

 While I am unable to comment on this, Wino may be able to review the link below and advise on the practicalities of swapping/coding a BCM. This was for an upgrade, but may apply to cloning your existing BCM.

 

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

I have a feeling that link is about a later BCM type.  As it's mentioning radio frequencies, I think it's one that combines the jobs of the Fabia Mk1 Onboard Supply Control Unit and the Central Convenience controller, so involves the locking systems etc.

I think the Mk1 Fabia controller is simpler, and requires less involved coding, if any at all. The link in my first reply above certainly made it sound reasonably straightforward, if VCDS is available.

On 20/01/2019 at 16:45, Wino said:

I have a feeling that link is about a later BCM type.  As it's mentioning radio frequencies, I think it's one that combines the jobs of the Fabia Mk1 Onboard Supply Control Unit and the Central Convenience controller, so involves the locking systems etc.

I think the Mk1 Fabia controller is simpler, and requires less involved coding, if any at all. The link in my first reply above certainly made it sound reasonably straightforward, if VCDS is available.

Well, just to close out this post. It's All Good News

 

Thank You, Wino, LightRain & Tech1e for all your helpful posts.

 

I got a unit off eBay for £25 and a friend came round with his VCDS software and downloaded data off old unit.  Swapped the new unit in and everything worked straight away. (most importantly RHS indicator with car running.)

We then ran a scan on new unit and code on "19. Can Gateway" was the same, but we changed the code on "09. Central Electrics" to match old unit and re-checked car. A-OK.

So, it was a fault on the original unit.

 

Even with some pub grub for friend & wife, we came in at £130 (including original diagnostic) instead of £500-600. I have donated my time to daughters free or the bill would have been mega.

That's about it - I'm off fishing - and thanks again.