[fine69]

A long read but I'd advise reading this before jumping on the VCDS bandwagon.

I understand that everyone wants to get basic VCDS tweaks done as quickly as they can on their new VAG car. I was also in the same boat and went to a somewhat popular "VCDS tweaker". Following week turned out to be a very difficult one.

My car developed a boot related fault and when the VW team was diagnosing it most of their initial hypothesis pointed towards incorrect coding. They told me that every other week some guy turns up with a weird problem and its usually because of coding experiments being done by them or by someone else on their car.

My problem was weird enough for them to think that it was a "coding gone wrong" issue. The boot wouldn't auto-unlock when I'd shut down the car and at times also used to pop open as soon as I'd move the car. The boot would open only on long pressing the boot button on keyfob. There is an option within VCDS to play with boot locks and it has a setting where the boot locks at 5 kmph. Whether one can really tweak that option is still unknown to me.

When I told the service center that this problem has been bothering me for a while the first question they asked me was whether I'd gotten some coding done from outside. Initially I didn't say that I did but when they spent 2 hours working on my car and decided to rip apart the car citing wiring problem I gave in, I told them that I'd gotten some basic tweaks done, including boot to not auto-unlock when the car shuts down and that's when the nightmare began.

They said that if I'd played with the Central Electric console in VCDS then it could have led to BCM issues and if they have to order a new BCM they need to upload the car's data on the server with the possibility that VW decides to not honour warranty on my car anymore because as soon as they read the logs they can make out that coding has been tweaked.

What a way to celebrate one month ownership of your new car. I was mortified and quickly pinged @fluidicjoy. Just in case I forget to say this by the end, had it not been for @fluidicjoy, I would've lost it, I mean my sanity. He helped me so so much, kept me calm & positive and was there all throughout my ordeal. Can't thank you enough mate!!

Since BCM is a relatively expensive part they told me that I would have to get the wiring checked but even they weren't comfortable looking for wiring issues in a one month old car. So they tell me that if its a coding issue then I should first go back to the tweaker, get the coding back to stock and if the problem still persists they can start checking the wiring.

@fluidicjoy did ask me whether this tweaker had taken a backup of stock log of my car before he made the changes. I didn't know so I asked the tweaker. He said that he'd do it once I bring the car to him again (which means he didn't). He did mention that he's never had that problem with any other car but he can take a backup once I take the car to him, he can then reset all lock related settings.

What I realized later was that he had enabled a setting for the boot to not auto-unlock when I shut down the car but funnily enough, that had never worked from the day I got it done.

Reason is because after getting the tweaks done I left for a long road trip and absolutely everything with locks was the same, the boot used to unlock automatically with all other doors when I used to shut down the car. But in VW service center I couldn't connect the dots as there was the dilemma of losing warranty hanging on my head.

I decide to go back to the tweaker and he plugs his laptop in the car again, doesn't take the backup of the existing log and starts enabling/disabling whatever was to be done to get all settings back to factory.

In long coding, he encounters one checkbox that was checked but didn't have any description, so he unchecks that. Basically this is when things start to go wrong but none of us realize that. He's done with his check up and points to a most likely faulty BCM as he's reversed all the settings and the issue is still not resolved.

I decide to take the car back to the VW service center but 2 mins into my drive I realize that the footwell light isn't going away. I call up the tweaker and immediately head back.

Again the laptop is plugged in, of course no backup taken still, and he fiddles with the settings again. He decides to play with the lock setting to turn something off (honestly I've forgotten what he did by this time) so that the footwell light doesn't come on anymore even if I open the door. I'm just glad that my car's battery won't be discharged in the night and while taking a test run we realize a new problem has cropped up, now the doors won't auto-lock when the car hits 15 kmph (or 20/25 kmph whatever the setting is).

Clearly this tweaker's fiddling is making this go worse but he again says that its nothing related to coding as he's reversed all settings so I should take the car back to VW and just say that I didn't get any coding done and if I have they should prove it.

This is the moment that I realize that I may have to pay for BCM from my pocket and basically start maintaining my car outside of VW because why pay for expensive service when the car won't be in warranty to begin with.

With a heavy heart I head back, I talk to @fluidicjoy and settle down a bit. He shares the stock long code with me and suggests to check if there's a mismatch. I head back to VW next day and ask them to take a look at the long code of my car. I don't tell them about the car not auto-locking doors at all as I would've buried myself deeper in the pit I'd already dug.

They show me the code and I try to match it with what @fluidicjoy gave me. There were around 8 entries that weren't matching anymore, 8 out of 20 odd entries I think. All this when the tweaker told me that everything was reset to factory settings!

The guy at computer tells me that I've probably toasted the BCM. I politely tell him that if I'm going to pay for the BCM as such, I'd really like to experiment until I see smoke coming out from BCM. They show complete reluctance in doing anything suggested by me anymore. Its not that they weren't trying to help, I mean they'd already spent hours a day before without even opening a job card but I guess they'd hit their saturation point.

After a few mins the guy at the computer agrees to put whatever code I tell him to put. The coding gets accepted and first thing I check is not boot but whether the car is auto-locking once it starts moving. A huge sigh of relief that everything is back to normal except the boot.

But this makes me more confident that the issue is most likely not with BCM and something else. I take their leave and decide to give the car to another VW workshop.

So while the tweaker thought he'd reversed everything he basically had no clue, no stock log backup so what do you even compare against. I don't know if deep down he knew he'd ruined it the moment doors stopped auto-locking but he was so confident or at least acted all confident that it had nothing to do with coding. My man, the boot may not have but everything else was your doing and you had no clue how to take it back to stock settings because you didn't take any backup, I hope you don't repeat this on your next car!

One day later though, everything is resolved, the boot works exactly as it should and I'm told by VW guys that there was a pin (somewhere towards the front passenger side wiring console) that was loose.

I message @fluidicjoy immediately upon taking the delivery of the car and again thank him, which he doesn't accept because as per him he didn't do anything but had it not been for him, I don't know what soup I'd have landed myself into. Thanks bro, you kept me sane, helped me troubleshoot the problem logically and kept reminding me that "we would resolve this eventually". I clearly remember you saying "we" and that was all it took, comforting words of a fellow bhpian sitting thousands of kilometers away helped me through this ordeal, much obliged!

Now my fellow bhpians, if there's one thing that you've learnt from all of this is that no matter what, always take backup of your stock long codes, before someone decides to play God on your car.

I remember @fluidicjoy and me discussing that this tweaker didn't mean to harm my car. Of course he didn't, but the lack of a proper approach meant that he worsened the situation even when he didn't want to. I'm not sure if he understands the impact of his actions because he didn't take the backup the second time also.

We also agreed that not all bits & checkboxes that don't have a description should be checked or unchecked just because they can be, the effect can be pretty dangerous. In my last visit to VW workshop for ceramic coating I met another fellow petrolhead who screamed BACKUP OF STOCK LOG, the moment I started on the VCDS topic. So I think some people have learnt it the hard way, some people have actually learnt it the proper way and then there's the other bunch whose mercy you're at if you're not careful.

I'm just glad that me and my car finally made it, thanks @fluidicjoy again!

Please be careful when you go to someone to get VCDS tweaking. The tweaker may have done it in thousands of cars but that doesn't mean things can't go wrong in the next one. Yes its right that an incorrect code wouldn't get accepted but look at what happened to my car the second time I took it to him even when all codes were accepted, they don't know half of what they talk about.

Today anyone with a rosstech cable & license can do it but it'd take a real professional to take a backup and verify that every single setting indeed is relevant to the car before deciding to play with it. Tweakers have nothing to lose and you stand to lose BCM or warranty or both!

[GTO]

Thanks for sharing, fine69! Moving your post out to a new thread so as to warn others. A new thread means 100X the views & 100X the visibility in search engines, including Google. Will add to homepage this weekend .

@ BHPians, if you should spot any good post in an existing thread that deserves its own new thread, please report the post and we'll move it out for greater visibility.

Thank you!

[Axe77]

Wow! This is quite the ordeal one has to go through with a brand new German car and I can’t begin to imagine what trauma you must have faced during these days. Really happy to note it worked out well for you eventually.

It does reinforce my belief now that with these complex Germans, you definitely shouldn’t do any serious tinkering for the first few years or until you’re out of warranty. It simply doesn’t seem worth it when you hear of incidents like this.

I think it would be instructive for the forum to also know who this tuner is (if you’re comfortable sharing of course). There are simply too many half baked experts out there and it’ll warn members from using his services whether or not their vehicle is within or out warranty.

[vishy76]

Valuable advice indeed here. A backup of the stock coding is a MUST if you intend to do any sorts of VCDS programming, no matter how minor it is.

I have personally known a Jetta owner who faced a similar issue after trying to code his car via VCDS. His LED DRLs and a part of the tail lamps stopped functioning completely and the indicator (on the tail lamp) remained on permanently. No matter what I tried to do after that (including checking another stock Jetta's configs and ticking the same boxes), the BCM just wouldn't respond to it.

Finally, he got in touch with someone on skype who helped him flash his BCM back to factory settings for a sum of around 40 euros. This solved the issue for good. This owner was lucky since he had the patience and knew where to look for a solution to his issues; any other average joe would have just replaced the entire BCM.

Here's a snap of the tail lamps. Notice the non functioning inner part and the permanently on indicator:


In the end, anybody who's using VCDS should make it a point to take a backup before making any changes to coding, no matter how minor those changes may be. Secondly, never rule a failure like this out and always have an escape plan in case the worst happens.

In the end, if you have a car which is under warranty and something similar happens, you are practically on your own. The O.P was lucky to have the ASC help him out in whatever little way they could and finally solve the issue. Not everyone might be this lucky.

[lapis_lazuli]

That was close! I think the VW dealership/ASS also deserves a pat on the back for being so accommodating. We are quick to point out shortcomings but this was surely ABCD on the part of the SA/technician. I was wondering, if we can create a compendium or a repository of stock codes (screenshot) of default settings by car accessed through VCDS just like we have a thread for user manuals.

[thanixravindran]

Originally Posted by fine69

A long read but I'd advise reading this before jumping on the VCDS bandwagon.

I understand that everyone wants to get basic VCDS tweaks done as quickly as they can on their new VAG car. I was also in the same boat and went to a somewhat popular "VCDS tweaker". Following week turned out to be a very difficult one.

My car developed a boot related fault and when the VW team was diagnosing it most of their initial hypothesis pointed towards incorrect coding. They told me that every other week some guy turns up with a weird problem and its usually because of coding experiments being done by them or by someone else on their car.

My problem was weird enough for them to think that it was a "coding gone wrong" issue. The boot wouldn't auto-unlock when I'd shut down the car and at times also used to pop open as soon as I'd move the car. The boot would open only on long pressing the boot button on keyfob. There is an option within VCDS to play with boot locks and it has a setting where the boot locks at 5 kmph. Whether one can really tweak that option is still unknown to me.

When I started reading this, I misunderstood the boot related fault as car is not booting up (starting up) and realized that it is a real 'boot' related fault in a car

This playing around of check boxes and coding (not sure you can call them as real 'coding' as I believe it is mostly some registry edits) looks like giving a prototype to testing team without documentation.

Glad you got everything back working. One word of caution - Lot of these default settings are directly tied to the initialization of those electronic circuits mainly to prevent them being damaged or just to keep them in known state (prevent source/sink any current from the micro controller IO lines). So please be a little careful with them. I won't dare to take a chance with a in-warranty car like VW/Skoda to play around these things.

[gjnnbagal]

Originally Posted by fine69

A long read but I'd advise reading this before jumping on the VCDS bandwagon
Now my fellow bhpians, if there's one thing that you've learnt from all of this is that no matter what, always take backup of your stock long codes, before someone decides to play God on your car.

Please be careful when you go to someone to get VCDS tweaking. The tweaker may have done it in thousands of cars but that doesn't mean things can't go wrong in the next one. Yes its right that an incorrect code wouldn't get accepted but look at what happened to my car the second time I took it to him even when all codes were accepted, they don't know half of what they talk about.

Tweakers have nothing to lose and you stand to lose BCM or warranty or both!

A very precarious way to go ahead with such tweaks, that too in an already complex German machines.
It’s like firing Nick fury and appointing Loki as head of S.H.I.L.D. I think the uncertainty of the final outcome from the tweak in an under-warranty car is enough wisdom to avoid undergoing such modification/remapping.
Not to mention it (might) be accompanied with voiding warranty, increased insurance premium, overall shortening of engine life/ increased wear and tear.

[Sen]

Another one joins the helped by "Fluidicjoy" club! I'd taken his advice as well on the steering veering issue (turned out to be a quirk of the new continentals) but the very first thing i did was take a backup of the stock coding!

Glad the issue was resolved for ya!

[Rocketscience]

Wow, that's a great lesson to learn, I always had my reservations with the tweakers, apparently they should not be approached even for minor jobs. There might be good ones too but not worth taking the chance.
The only thing i'd like to tweak in my next car would be to remove the 80 and 120km/h warnings which is just a silly rule by our authorities, instead of ECU, i'd rather find and remove the buzzer/speaker and be done with it.

[PearlJam]

First of all, thank you for describing your ordeal in detail! This is very useful information for someone wanting to foray into VCDS tweaks.

Originally Posted by fine69

When I told the service center that this problem has been bothering me for a while the first question they asked me was whether I'd gotten some coding done from outside. Initially I didn't say that I did but when they spent 2 hours working on my car and decided to rip apart the car citing wiring problem I gave in, I told them that I'd gotten some basic tweaks done, including boot to not auto-unlock when the car shuts down and that's when the nightmare began.

........
Clearly this tweaker's fiddling is making this go worse but he again says that its nothing related to coding as he's reversed all settings so I should take the car back to VW and just say that I didn't get any coding done and if I have they should prove it.
...
...

They show complete reluctance in doing anything suggested by me anymore. Its not that they weren't trying to help, I mean they'd already spent hours a day before without even opening a job card but I guess they'd hit their saturation point.

Sorry, I have to be very blunt here. When they specifically asked you whether you had done any coding outside, you denied it in the beginning, but admitted so later on. That itself would reduce their trust in you, isn't it? Their complete reluctance to try out your suggestion later on, seems to confirm that point.

At the programming level, if VW/Skoda digs deeper, they can conclusively prove, or atleast convey enough doubt (from logs/timestamp/write count/etc - there is no such thing as a perfect crime!) that it has been re-coded. So there was no point denying that, though I guess you were fortunate that things didn't reach that stage regarding warranty.

Added to that, the coder saying "take the car back to VW and just say that I didn't get any coding done and if I have they should prove it." - just doesn't cut ice, apart from being the wrong thing to say.

Yes, a mistake was made, but you were fortunate to recover relatively unscathed, and without much collateral damage (I guess it's a good lesson to learn for the rest of us too). But if you couldn't, it could have probably gotten messy with the warranty. I guess the best thing to do here would be to honestly come clean, admit your mistake, and beg them to restore stock settings without voiding the warranty. I am sure they would oblige, since nothing really was wrong with your car otherwise.

Hope you take this in the right spirit.

[aashishnb]

Originally Posted by fine69

I was also in the same boat and went to a somewhat popular "VCDS tweaker". Following week turned out to be a very difficult one.

Shouldn't you give the name of the popular tweaker in BIG BOLD for other members to be careful about & insist on a full backup, if they wish to use his/her services.

Also, if one has the patience & more importantly the tweaker allows, perbaps doing a full video recording of all changes might be helpful to reverse exactly the things that were changed - kind of a 'change log'.

[nightraven]

I never tweaked VCDS but used similar tweak softwares extensively for my Ford. I even accidentally bricked and brought modules back to life. Microcontrollers getting burnt or EEPROM corruption due to incompatible VCDS coding on variants with different wiring is a major issue. It is always recommended to make a backup of stock car settings before touching any software and maintain a log of what was done at each step to track changes.

You have learnt it the hard way but glad that your boot issues were resolved. Not familiar with VW cars, but does VW have an open web portal where you can get stock hex codes like for Ford with a VIN code you can download a copy of your stock codes?

[vennarbank]

Originally Posted by nightraven

I never tweaked VCDS but used similar tweak softwares extensively for my Ford. I even accidentally bricked and brought modules back to life. Microcontrollers getting burnt or EEPROM corruption due to incompatible VCDS coding on variants with different wiring is a major issue. It is always recommended to make a backup of stock car settings before touching any software and maintain a log of what was done at each step to track changes.

You have learnt it the hard way but glad that your boot issues were resolved. Not familiar with VW cars, but does VW have an open web portal where you can get stock hex codes like for Ford with a VIN code you can download a copy of your stock codes?

Off topic. Can you please let us know the location of source code for Ford cars.

[Dry Ice]

Glad you were able to fix things eventually. And a very valuable lesson learnt as well. You don’t change stuff without having a rollback strategy. That rollback isn’t possible without a proper backup.

Sorry if I missed it, but, what was it that you wanted enabled via VCDS coding and on which VW car?

[Sahil00090]

The stress you must've gone through this, I can understand to some extent. But glad it's all sorted for you.

Just to get an Idea, what's the cost of new BCM? Did the SS quote any rough estimation?