Brake light problem in 6R Polo

[Hillbilly]

Our 2010 Polo Comfortline has been showing a bulb out warning on the dash for quite a while.. None of the bulbs were actually out. Took it for a service last week and they told me brake lights werent working. VW had said they thought it was the brake light switch so we changed it. Still out

Took it to VW today and they have diagnosed a faulty BCM for $1340 fitted.

Strangely yesterday when taking it over to VW the lights decided to work and are still doing so.

Tech said BCM was only outputting 9V to the lights and thats why they werent going.

So why are they on now???????

Question Will a second hand BCM fit and work or will CP cut in even if its the identical part number.

Am a bit leery on VW after they told me the drivers seat in my prev Passat needed a whole undertray and motor for $1013 and me charging the batttery fixed it

Anyone got any ideas for a cheaper fix as want to sell it and buy a T-Cross or a Kamiq

UPDATE Ran battery down yesterday to 9.5 V and brake lights wouldnt work.

Put the Ctek on it and after charging for 10 hours battery was up and lights work

SO IS IT THE BCM or is it the BATTERY.

However at 9.5v it wont start the car so I guess i will have to dig deep

[kamold]

6R BCM doesn't have Component Protection.
So you can get one from a wreck, just copy over the long coding from the old BCM.
If your battery is on the way out that obviously is a problem. The BCM can't make it's own electrons.
If your battery is healthy and putting out a proper voltage and lights work, then seems like you've found the problem.
If with 12v from the battery the lights are still at 9.5v then it is likely the BCM.

[Lucas_R]

If you are on the original battery i dare say its at the end of its life. Have you had the battery tested?

[Hillbilly]

Thanks to both The car has a new battery less than two years ago and taking a reading with OBD yesterday it was on 12.3 The old one was 7 years old and was a bit reluctant to start car and about this time the light problem started .
The little icon came up on the dash but until last week the lights always worked fine. were working when went to local guy for a service as I followed it to there. on picking it up they said they werent working and so they changed the switch but didnt fix it.
Brought it home and left it in garage for a week and made a time with VW . On backing out to go to VW the lights worked and are still doing so if the battery is above 11v

Do I need actual part number with correct suffixes or just any identical looking one. Part no is 6R0 937087T Z0T Only place I can find one is here

so not a lot cheaper 6R0937087TZ0T Ctrl Unit VOLKSWAGEN genuine spare part online

[Lucas_R]

Separate the part number into xxx xxx xxx etc and you will find better Google results

VW POLO 6R BODY CONTROL MODULE USED 6R0 937 087 M - Parts 4 European Cars

COMFORT CONTROL MODULE VOLKSWAGEN SEAT SKODA CONTINENTAL A2C53362300, 6R0 937 087 D, 6R0937087D, 5WK50147 (1) (1) auto24parts

[Hillbilly]

Thanks VW said it has to be the EXACT part so does the suffix like mine is T ZOT and some are M and K etc make a difference and how would I flash it with my software

[kamold]

It just has to be a 6R0 BCM high. Doesn't have to be the exact same part number. Has to be a compatible part.
What's the hardware and software part numbers and revision as reported in VCDS/OBD11?

[Hillbilly]

Ok here are results Car now has 12.4v with ign on only. 14.3 idling.

Scanned all the modules and only got low voltage ones from running battery down yesterday.

Cleared them and scanned again NO FAULTS

So the open circuit 2 have gone and brake lights are working again. Still have bulb out icon on dash after clearing faults

I think I will go and talk to Euro Car Upgrades and see if they can use a s/h one and reprogram it to mine


WOULD THIS ONE DO VOLKSWAGEN VW POLO 6R 2010 77TSI BCM FOR CONVENIENCE SYSTEM 10-14 A2C53396761 | eBay


Here is the OBD scan

[kamold]

Yes that's the same BCM as what you have.

[Hillbilly]

Yes that's the same BCM as what you have.

Thanks went to Eurocarupgrades today and they said they can do two things Replace the chip that governs the output voltage or buy that one and hope its similar and pair the immobilizer to my remotes..

Sound sensible About half VW price


Do you know the result of altering the K number in module 17 Dashboard as I have done it and cant remember what I was trying to do.

They wondered if fiddling has made the warning light come on as it only comes on if i touch the brakes