Replacing battery reset ecu?

nuga

Well-known member
Joined
Apr 5, 2011
Location
KC, DC
TDI
jetta 04' manual
Does replacing your battery reset your ECU? I have a tune i dont' want to lose over a stupid battery. I went to the VW dealer in DC and thats what they were trying to tell me?

they were trying to install it and they said they did stuff with thte computer for $216
 

PeterV

TDIClub Enthusiast, HO5G Doyen & Zen Master
Joined
Aug 17, 2000
Location
So, NH.
TDI
2000 Jetta 5 sp.
Whose tune? The Batt replacement should have NO effect on your ECUs tune

And why do you go to the stealer.... you have a 9 year old car..

The Battery is one of the few things you can still do your self.
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Does replacing your battery reset your ECU? I have a tune i dont' want to lose over a stupid battery. I went to the VW dealer in DC and thats what they were trying to tell me?

they were trying to install it and they said they did stuff with thte computer for $216
no, but the "did stuff to computer" may have wiped your tune
 

nuga

Well-known member
Joined
Apr 5, 2011
Location
KC, DC
TDI
jetta 04' manual
rocket chip. I've heard that when you disconnect the battery a bunch of computer settings and such get reset.. I don't know what that means. And i do very little/no work on my car except oil changes and wipers and bulbs
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
Are you saying they charged $216 to change the battery and you're looking to see if it's justified because they did "stuff"?

Or they did "stuff and now want $216 more?

What are you asking?
 

Seatman

Top Post Dawg
Joined
Apr 23, 2010
Location
Scotland
TDI
2014 Skoda rapid elegance 1.6 cr tdi
If you're saying that the dealer charged you that much to change the battery you have been what's known as ripped off.

As said having the battery off wont change anything in the ecu at all, it has no effect. The ecu has memory in it more like what you'd find in a usb pen drive, you stick stuff on it then take it from one computer to another and your info is still there, it's exactly the same with your ecu.

I would asking for an exact list of what they did then post back for some advice.
 

OlyTDI

Veteran Member
Joined
Dec 18, 2007
Location
Olympia, WA
TDI
'04 Golf
If I recall, when I replaced my battery, I was worried about losing the radio and immobilizer (not sure where I'd heard that). So I just made sure to connect the new battery while keeping the old one connected (no disruption in continuity). I think I found out later that this was unneccesry (at least on a '04).
 

nuga

Well-known member
Joined
Apr 5, 2011
Location
KC, DC
TDI
jetta 04' manual
they were saying they were going to do stuff to the computer... but didin't exaclty tell me what that was.

that said. It was 216 with battery installed... I am visiting my folks so i can't put it in myself. I'm basically asking how does replacing your battery affect anything on the car. or is it like any other car... no big deal.. :)
 

\/\/0J0

Veteran Member
Joined
Apr 27, 2010
Location
Knoxville, TN
TDI
Sadly, none anymore
It should be like any other car. No big deal. It resets your presets on your radio and clears your trip meter. The cache is cleared on the ECU but your tune remains. If a tune was cleared out every time a battery was changed, then that would hold true for the stock tune and no one would be able to drive their cars after their batteries died. Your RC tune overwrites the stock tune; it lives in the same chip that the factory tune once occupied. I would be interested in what "stuff" they did to your ECU, though. Hopefully they didn't "upgrade" you to the latest stock tune.
 

nuga

Well-known member
Joined
Apr 5, 2011
Location
KC, DC
TDI
jetta 04' manual
thanks to be clear i didn't let them touch my car once they said they were going to do stuff to my computer...
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
I guess I just don't understand why you don't just ask them to replace the battery and do nothing else. Or purchase the battery and find someone else to install it.
 

nuga

Well-known member
Joined
Apr 5, 2011
Location
KC, DC
TDI
jetta 04' manual
thats what i'm going to do... i just wanted to verify that nothing else happens when i replace the battery
 

nuga

Well-known member
Joined
Apr 5, 2011
Location
KC, DC
TDI
jetta 04' manual
Sometimes when the battery is run low or disconnected the throttle body and ECM will lose adaptation. This will cause a high or low idle and sometimes will cause a MIL to be illuminated. This mostly caused problems with 95-99/00 cars with cable driven throttle bodies. The throttle body was moved by a cable linked to the accelerator pedal but the body also has a sensor and a motor so the ECM can increase idle speed if needed. A factory scan tool or vagcom (www.ross-tech.com) scanner can perform the adaptation to reset this.

Also, earlier cars can have the radio go into SAFE mode until you put in the security code to unlock it. Likewise the windows will not auto up/down until you run them up and down a few times.


i found this in the vw forum
http://volkswagenownersclub.com/vw/showthread.php/26779-Disconnecting-battery-dire-consequences


thats why i am asking questions.
 

jetta 97

Vendor
Joined
Dec 25, 2008
Location
Dallas (McKinney) ,TX ,USA
TDI
2 X Jatta MK5 2006
--TDI does not have throttle body.

--Radio code you may find instruction and CODE in owners manual book.but if you have 2004 model,CODE will not be lost. CAN BUS remember CODE and radio will work fine.

--Windows is very easy to reset,
Put key in cylinder lock and with all windows up unlock car and hold key to
unlock position. Windows will roll down.After they roll down lock car and hold key to lock position. Windows will go back up and they will be reset.
 
Last edited:

Genesis

Top Post Dawg
Joined
Feb 26, 2003
Location
Sevier County TN
TDI
'03 Jetta Wagon
I've not lost the code on my 2003 pulling the battery, and have had to do so to get to the wiring channel under the airbox and such.
 

n1das

TDIClub Enthusiast, Veteran Member
Joined
Jun 11, 2002
Location
Nashua, NH, USA
TDI
2014 BMW 535xd ///M-Sport, 2012 BMW X5 Xdrive35d, former 3x TDI owner
There is no "throttle body adaptation" to do since a TDI doesn't have a throttle body. If the car still has its stock radio, the radio and the car will automatically recognize each other and no radio code is needed. Radio station presents should be retained. Basically you can have have the battery disconnected as long as you want and not lose anything important. The clock on the instrument cluster will need to be reset and the trip meter will reset to 0 upon connection of the battery but these aren't any big deal.

Good luck.
 

nuga

Well-known member
Joined
Apr 5, 2011
Location
KC, DC
TDI
jetta 04' manual
I love tdi Forums. Thanks for the help - i took it to a different dealer -
149.99 total installed (the dealer was running a special.) 160 including taxes + they washed my car ...
:)
 
Top