Dead Battery and Computer

2003VW

Member
Joined
May 11, 2011
Location
Darlington, MD
TDI
2003 Jetta
A friend of mine told me that if the battery goes totally dead or is disconnected on my 2003 Jetta TDI that the program in the computer will be lost and need to be reflashed at a dealer. My battery is getting weak and I need to replace it and don't want to mess any thing up.

Can any one clarify this? I have searched this forum but couldn't find any info related to dead batteries and the computer.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
You need a new friend.

The only thing on your 2003 diesel that you'll have to do is reset your clock and your power window pinch protection.
 

2003VW

Member
Joined
May 11, 2011
Location
Darlington, MD
TDI
2003 Jetta
New Friend

He is a good friend, although misinformed, and I would say true friends are harder to find than decent cars.

Any way, thanks for the information. I can get my new battery and change it with out any worries.
 

whitedog

Veteran Member
Joined
Jul 12, 2004
Location
Bend, Oregon
TDI
2004 Jetta that I fill by myself
I have found that if a battery is dead for a couple of years, sometimes the Engine module needs to be reset with VCDS. I had this happen with a POS I bought. It had sat for well over a year and I had to go to the engine module in adaptations, read it, then save.

I have that is a thread someplace where MoGolf helped me with it.

YOU shouldn't have any troubles with that.

Edit:

Here is what Mogolf told me:

Go to the cluster, clear codes even if you don't see any.
Go to its adaptation channel 00, read and save.
Go the the engine controller, clear codes even if you don't see any.
Go to its adaptation channel 00, read and save.
Turn off the car. Wait 1 minute.
Turn on the car and try to start the car.
If the immobilizer light is flashing, you need to resync the key(s).
 
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