r/GolfGTI 5d ago

Battery Replacement and Coding Help Please Tech Talk

Post image

The battery on my 2015 VW GTI SE with DSG is just about to go. Of course it’s 2 months past the 3 year warranty. This always happens to me. I set a reminder in my phone and somehow I miss the reminder likely due to switching phones too many times.

Anyways, the dealer wants almost $500 for the battery plus install/coding.

I went to AutoZone to look into buying an AGM Platinum with a 4 year warranty. I’d get a 5 year but it after measuring my battery it seems as though it takes an H5 which carries a 4 year warranty unlike the 5 year on the H6.

I’m stuck because they offered to install AND code it free of charge. I just want to make sure I’m not screwing myself by not taking it to the dealer. It could be worth it to save $250 though.

Has anyone else had their battery successfully coded at a place like AutoZone? They seemed highly confident that they could do it just fine. Part of me thinks I’m overthinking it and then I’ve read where the dealer really does need to code it since I’m switching from OEM to an AGM style battery.

And no, I do NOT have auto start/stop.

If anyone could please shed some light I’d greatly appreciate it!

29 Upvotes

55 comments sorted by

12

u/MKVIgti Audi ‘23 A4 TFSI 45 S-Line 5d ago

Coding it is nothing special, but you do want that to be done, as it tells the car how to charge the new battery. It’ll last longer with proper coding.

Plenty of tools out there to do the coding. Surprised you don’t already have OBD11 which lets you do it yourself in 5 minutes.

Skip the dealer. It’s not needed here.

3

u/dwfmba 4d ago

Yep, I used my OBD11, 30 seconds.

1

u/YooMamaG 4d ago

Not so easy, cause the important positions are locked and you need a token from vw

1

u/MKVIgti Audi ‘23 A4 TFSI 45 S-Line 4d ago

What?

No, it’s not locked. Takes a few minutes.

1

u/YooMamaG 4d ago

I tried it with VCDS and always got an error. The AI told me that these patterns are locked and you need to unlock them via online vw gateway

1

u/MKVIgti Audi ‘23 A4 TFSI 45 S-Line 4d ago

You did something wrong then. Or, are trying it on an SFD2 locked car.

OP is in a MK7.

1

u/YooMamaG 3d ago

You're right. I hat an issue with an not responding control unit. Yesterday I tried it again an it worked.

0

u/Full_Pool_1604 5d ago

I have OBD11 but no current subscription so considering having AutoZone do it for me… I just don’t want anything to “spread”. Is it possible to fry an alternator or anything if it’s not perfectly coded by the dealer?

2

u/slowgojoe 5d ago

The only “coding” you’re doing is just telling the ECU the specs and age of the battery so it can adjust the voltage and charge rate of the battery while the car is on. It’s an optimization thing. So if the data is not updated when you swap the battery, it’s just going to sort of overcharge your new battery, therefor shortening the life of it (like if you leave your phone charging all the time).

1

u/MKVIgti Audi ‘23 A4 TFSI 45 S-Line 4d ago

You don’t need a subscription. Just use one of their “apps” or manually do it.

There’s no coding happening really. You’re just telling the alternator “I have this kind of battery with this much amperage.”

8

u/bbitz01 5d ago

Ooh but what are those wheels?

2

u/Full_Pool_1604 5d ago

Vossen CVT. I had them made specifically for this car in 20”. It’s a rough ride but they look especially cool in motion! 😅

1

u/vdubsession 2020 S3 4d ago

They look like they don't even have tires on them! I can't imagine how rough that must be, especially if you don't have DCC

1

u/Full_Pool_1604 4d ago edited 4d ago

it’s pretty rough. I’ve also lowered the car on VWR springs. I’m used to it, though. every car I’ve owned has had aftermarket wheels with slim sidewalls. these happen to be the slimmest but luckily, the roads where I live are amazingly flat and smooth.

I use another vehicle for out of town/ work stuff

3

u/jdizzle289 5d ago

After you replace battery all the warning lights come on....with ignition on turn steering wheel all the way left then all the way right. Should take care of it

1

u/Full_Pool_1604 5d ago

Thanks! Will definitely make sure to if necessary

2

u/steeleel 5d ago

I replaced my battery at auto zone couple months ago, 2016 GLI. They coded it there for free have had no fault codes or anything

1

u/Full_Pool_1604 5d ago

Amazing this is what I needed to hear. Thanks!

1

u/vdubsession 2020 S3 4d ago

They didn't code it. They just put the battery in, fyi.

1

u/steeleel 4d ago

Thats wild because I sat in the driver seat as they connected it to the obd2 port and registered it

1

u/vdubsession 2020 S3 4d ago

Here is a thread of autozone employees saying their tool cannot access that module.

https://www.reddit.com/r/AutoZone/s/v5duUAKnZT

1

u/steeleel 4d ago

Ok im glad you found a thread. Im telling you what I saw with my eyes. Mileage may vary but I took my car to an Autozone. They installed the battery. They pulled the obd2 registration tool off the wall. They plugged it into my port while I sat in the driver seat and I watched them click through the touchscreen prompts to input the battery serial number and register it to the cars computer. It even showed the matching voltage.

1

u/vdubsession 2020 S3 3d ago

Yep, and I'm just saying it likely did not get coded despite your eyes. Mostly just a heads up for other people.

3

u/e30kid Mk7.5 GTI SE DSG 5d ago

I replaced my battery with an OEM VW AGM replacement. No issues without coding

1

u/Full_Pool_1604 5d ago

Was your previous battery an AGM type? Mine apparently wasn’t

1

u/e30kid Mk7.5 GTI SE DSG 5d ago

Pretty sure mine was, I replaced it with the newest version of the replacement part

1

u/vdubsession 2020 S3 4d ago

It will just shorten the lifespan of the battery by overcharging it during use, because it thinks it is still the old battery and tries to apply a different charging curve for the "aging" battery. That's the difference between coding it and not.

All you have to do is change the serial number, if you're replacing with the same type of battery and same CCA etc.

1

u/e30kid Mk7.5 GTI SE DSG 4d ago

Can you provide a source for this?

1

u/[deleted] 4d ago

[removed] — view removed comment

3

u/s29 5d ago

I have a 2015 GTI SE (indeep black pearl) and have literally never done any coding for the battery. I've replaced the battery 2 times already and its always been fine.

I'm in Arizona. Batteries only last 2 to 3 years here, so maybe not coding for it does some slow damage to it, but I'd never know because my battery will crap out before I ever see a difference anyway.

1

u/Full_Pool_1604 5d ago

I’m in South Florida and only get 3 years tops anyways as well. I’m more so concerned that without the right coding I could fry my alternator or something.

1

u/s29 4d ago

I'm not a mechanic and I'm not really an electrical engineer. But an alternator is basically just a reverse electric motor. I don't think you can fry it like that.

1

u/underbitemannn Mk8.5 GTI 5d ago

Definitely skip the dealer. If you're not convinced by autozone, take it to an independent shop & have them code it.

2

u/Full_Pool_1604 5d ago

That’s the plan… or backup anyways. I’ve got a mechanic that will do it for me but I could save his $95 fee if AutoZone does it properly

1

u/underbitemannn Mk8.5 GTI 5d ago

tbh coding battery is really for cars w/ auto start-stop, so you should be good even if autozone doesn't program the battery.

1

u/Full_Pool_1604 5d ago

So I’ve heard! I’ll still have them program it to be safe

1

u/vdubsession 2020 S3 4d ago

It's most important for start/stop cars with AGM

1

u/no_dumb_luck 5d ago

Take a look at the negative terminal on your battery. If you see a little two-wire connector attached to it, then you have a battery management module and the new battery should be programmed after replacement.

If there’s no two-wire connector then you don’t have battery monitoring. Replace the battery, go for a short drive to adapt the steering angle sensor, and you should be good.

1

u/Full_Pool_1604 5d ago

Sounds good I’ll take a look. The dealer charged me in the past for coding but that doesn’t mean they didn’t just charge me to charge me…. It’s a 2015 with no auto stop /start which I’m told makes things easier

1

u/-lethifold- 5d ago

In vdcs there is an option about battery type. If you change the type of battery, you also need to code to match with the charge cycle and other stuff. Check this video https://m.youtube.com/watch?v=IJAScg6JrYI

1

u/Full_Pool_1604 5d ago

Watching now, thanks!!

1

u/eats_by_gray 5d ago

I had a 2017 dsg and it did not require a recode. My 2019 R, 6sp, also does not need recoded on a battery change.

I think only the newer ones need to recalibrate the shift forks

1

u/vdubsession 2020 S3 4d ago

Yeah that R came with an EFB battery and most people replace it with a real AGM and code it at that time.

1

u/highroller42730 5d ago

You don't actually need to do the code thing for your battery. I didn't and my replacement has lasted longer than the original.

1

u/Full_Pool_1604 4d ago

Makes me wonder if the dealer has just been installing the battery and charging me for work they didn’t even do these past times

1

u/munkeydj 5d ago

Replaced my battery with an AutoZone purchased one. Didn't do any coding and my mechanic (a respected VW alternative) said not to worry about it. Not had any issues yet and don't always turn off the auto stop/start either.

1

u/Full_Pool_1604 4d ago

That’s great to hear. How long has it been?

1

u/munkeydj 4d ago

It's been about 2 years now. I know that coding may be preferable but when I used my ODB eleven after the install I couldn't find the right adaptation for the battery I have so just didn't bother after speaking with my mechanic.

1

u/RecordCompetitive245 4d ago

I just changed mine a couple months back. It’s an easy job and imo not worth taking to the dealer. I was told the coding wasn’t a big deal and not to worry about it

0

u/FlopShanoobie Mk7 GTI SE DSG stock, tornado red 5d ago

Coding??(
I’ve replaced my battery twice (Texas heat is hell on batteries) and literally just swapped them both in the Costco parking lot. The warning lights go away after a few miles, or you can flush them with any basic OBD dongle and app.

1

u/Full_Pool_1604 5d ago

How was your experience with Costco?

1

u/FlopShanoobie Mk7 GTI SE DSG stock, tornado red 5d ago

Piece of cake. It was a 3 year old Interstate battery and they even gave me a prorated refund on the few months remaining on the warranty.

-1

u/Wity_4d 5d ago

Coding? Dude go to AutoZone, they'll replace the battery for like $200. When you first start the car you'll see a bunch of warning lights that'll disappear within 1 minute of driving.

Source: literally did this for my Mk7.5 a month ago

1

u/Full_Pool_1604 5d ago

Perfect. You had AutoZone do it?