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Complete power loss during acceleration (new battery)

8922 Views 22 Replies 13 Participants Last post by  vwpwr
Hey guys,

OK I had to put this in the forums just because it has irritated me greatly the last couple weeks and I've been without my B5 now for over a week.

Heres the story...

I was down at the in-laws visiting when the car refused to start as we were leaving the grocery store. All guages and lights inside the car were going crazy and relays were firing like mad. I immediately assumed the battery had just miraculously gone completely dead in a 15 minute period... OK fine the battery is almost 6 years old. So, Advance Auto shows up and puts a new battery in, car starts up fine and idles fine. But when I go to give it gas, RPM's rise to about 1200 and then it falls right back to idle like someone yanked my foot off the throttle. I'm driving a 5-speed to I can't even get the car moving with 1200 RPMs.

So AAA ends up towing the car to a local stealership where I am told they are an "authorized" VW repair facility. The proceed to play with the car for a week and eventually shrug their shoulders saying they can't fix it. The CEL points to a throttle body error but everything they try doesn't change anything.

I called my regular stealership back home and Jim (the man) says "Oh yeah if you had a dead battery, most likely you need a throttle body adaptation... you mean they didn't perform one???" So now my car is being towed back home so my dealer can do this 30 sec. TB adapt. So 250 bucks, 2 tows, and 12 days later, I think I finally get to drive my car again.

My question is, has anyone else experiences similar problems after replacing a dead battery? Is it worth my money to go get the Vag-Com so I can do the TB adapt myself (assuming that is really the problem here)?

As always, thanks for the insight!
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to replace the battery, you have to do a "throttle body adaptation?" I'd be interested in knowing just wtf this is...
I have a 99 that I assume will need a battery in a year or so.
i know you can do an entire TB adaptation with the vag-com, but i also know you can just turn the key to fully on power, without the engine, leave it like that for 3-5 min and your done. i duno if that is all that is required or not after installing a new battery.
That's weird. I replaced the battery in my 99 V6 with an Optima Yellow Top and I didn't have to do anything but put it in.

Paul :thumbup:
They did that process on mine when I had my battery replaced....went bad after a year.

I think this may be a common misconception on the forum here, putting the key in with the hood up and door open and turning it on for 3-5 min (not running) is not the TB adapt. Believe me I tried that about 10 times with disconnecting the new battery in between tries. It didn't help at all. My local dealer also tells me the TB adapt can ONLY be done via the Vag-Com.

Car goes in to the shop on Tues. so I'll let everyone know what they did to fix my problem (Jim tells me he is going to start with the TB adapt though)

Thanks Chris for the info, keep us updated, it just seems so unreal that you have to do that when you change a battery :???: . Mine is an 01' with the 1.8T 5 speed and i sure hope i could change the battery without going thru this crap, geez, hope to get the same luck then Quality_Sound :lol: . Let us know how it went and good luck :thumbup:
Humm, I think there isn't such a thing as"TB adaptation". What would be the adaptation for?!?! What would be the exact purpose of it?!?! I replaced my battery myself last year (All I have is a tape player and I had my cd player hooked up to the cigarrete lighter outlet and forgot it on, till next day; that's how I managed to drain my battery completely out! :oops: ). Anyways, the ultimate care I had to have was to make sure I disconnected the negative first! BTW, I drive a 99 1.8t manual . BTW #2, I just read my Haynes manual, and I just can't find anything such as a "throttle body adaptation", neither on the battery replacement description, nor on the throttle body section (which is 3 different sections: tb removal and installation, tb control module, removal and installation, and throttle position sensor, this one being for V6 models only!). PS: I'm going to try to call my stealership tomorrow, see if I can get any information on WTH this tb adaptation is. I'm not sure though how they're working their schedule since it's memorial day weekend.
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TheJezter, your problem sounds quite normal to me. I get exactly the same problem if I remove the power from the ECU. For me, the fix without VAG-COM was to remove the negative lead from the battery for 15 mins, then reattach it. Then I'd turn the ignition key to the ACC position and go to the front of the car and listen to the throttle body motor. If it didn't whir for about 30 seconds, I'd turn the igtion off and try again.

Now that I have VAG-COM, all I do is the throttle body adaptation (TB adaptation) and if I get a "failed" result, I turn the igntion off and try again.

For all those people that are thinking it makes no sense to do a throttle body adaptation if the power is removed from the ECU, you should have a read of the VW service manual for the "Motronic injetion and ignition system". To quote page 24-121:

Procedure after voltage supply open circuit
If the voltage supply is interrupted, the engine control unit looses all the "learnt" and/or "basic" values. Therefore considerable dirving characteristic problems may occur depending on vechile milage.
Work sequence
Performt the following operations after voltage supply open circuit:
- Switch ignition on for at least 10 seconds
- Switch off ignition.
- Adapt the engine control unit to the throttle vavle control part
=> Page 24-129

Page 24-129:
Adapting engine control unit to throttle valve control part
Adapting teaches the engine control unit (with ignition switched on and engine not running) the throttle valve control part stop postitions and a comparison graph between throttle valve potentiometer and throttle valve positioner sender.
Adapting sequence must be performed if:
- The voltage supply is interrupted
- Throttle valve control unit is removed and installed
- The throttle valve control unit is renewed
- If when installing another engine another throttle vavle control unit is installed
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I love how we get replies all over the board... and VWPWR.. buy the bentley manual, the reason your haynes manual doesn't have the TBA in it, is because they haynes line is pretty half-assed when it comes to actual technical manuals. I've done the TBA on mine and the Woman's car at least 5 times because of unhooking the battery etc. and the Vag-Com has paid for itself hundreds of times over in the process.
Damn, I guess you were right (nah, you guys are right :thumbup: !) I called the stealership and they said the same thing. For you TUR-80, I don't have the owners manual since I bought my car used and they removed it out of it. And Jbough389, I guess I'll have to invest on a Bentley (the manual that is :D ). It's funny though that this happens "sometimes" (since it didn't happen with me nor quality_sound). Why would that be?!? What differences engine wise would exist in order for the tb adaptation really be needed?!? I think it can't be the engine size, since I have a 1.8t and quality_sound has a V6. Anybody?!?! BTW, it's because of moments like this I :heart: club :b5: ! You live you learn, if you don't, you haven't lived long enough!

Excellent write up :thumbup: This is exactly what this list of posts needed! I wish I had the manuals to read about it myself!

Question to all, does anyone have the definitive answer as to whether you MUST have a Vag-Com to do the TB adapt since we now know you must do it after complete power loss?

It would be nice to once and for all figure out what the difference is between a Vag-Com TB adapt and putting the hood up and key in for 2-3 min. Does the manual explain what that procedure even is??? Since my car doesn't go in until Tues. I may drive over there tonight and try disconnecting the battery, and doing the 2-3 min. key in on position deal. Not that I don't trust the first dealer that worked on my car :roll:

I will let everyone know what I find with trying this procedure and if it doesn't work, what the dealer did to fix it.

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Indy 500 going on right now, I wonder if I can drop one of them engines in my :b5: WOO HOO!!! :D

TheJezter said:
Question to all, does anyone have the definitive answer as to whether you MUST have a Vag-Com to do the TB adapt since we now know you must do it after complete power loss?

It would be nice to once and for all figure out what the difference is between a Vag-Com TB adapt and putting the hood up and key in for 2-3 min.
When you turn the key to the on postion (without starting the engine) and you can here a whirring noise from the throttle body motor, people assume the car is doing a throttle body adaptation. However, all that is really happening is the throttle body motor is holding the throttle plate open at part throttle to help with the starting of the engine. If you perform a throttle body adaptation, the sound is different.

If removing the negative cable for 15 minutes didn't work for you, I'd suggest finding someone that has a copy of VAG-COM. If you can't do that, you'll have to see the dealer.
OK, here's the update. I went over to see my car tonight and try to do a manual TB adapt by putting the key in the on position. I disconnected the battery for 15 min. (while I waited for the thunderstorm to subside :eek:h: ) then I put the key in the on position and I heard the usual 1/2 sec. whir but nothing else. I tried removing the key and turning it back to on a few more times and no go. So it looks like my 99 isn't going to cooperate and realign itself the easy (and free) way. So I'll let the dealer have at it and let you all know what they find. Meanwhile, I am going to seriously think about investing in a VAG-COM.

Of course, all this begs the question, why on earth would VW design a vehicle such that whenever the battery dies or is disconnected, the vehicle is then inoperable until being attached to a VAG-COM???

I'm hoping this isn't the default case because many others have written in saying they have not experienced this problem after changing batteries... I'm all out of answers :???:

Not only have I changed out my battery twice, but Ive also done tons of installs on not only Passats, but NB, Jettas, Golfs, A4s and A6s, all of which I've disconnected the negitive terminal. Never have I had to do a TBA for simply removing power.

TheJezter--What it sounds like to me as if something more than just a dead battery was wrong with your car. Perhaps the CCM or ECU is bad and thats what drained the power.
I just swapped my factory battery on my 2001.5 V6 for an Optima Yellow Top and it worked immediately. By the way, everyone with an OEM battery be sure to check the fluid levels. Mine was bone dry! :???:
I'll second on checking the fluid level. Our batteries are a high maintenance variety. I top off my battery twice a year. In Florida our batteries will not last 2 years without regular maintenance. Mine is 4 years old and going strong. :lol:
I have seen other VW cars such as beetles and Jettas require TB adaptations after dead batteries. Once the check engine light comes on then you have to put the VAG-COM on it. Part of doing an Adaptation is clearing all the DTC's, so if you start the car and the check engine light does not go off the car will need an adaptation. If you install a new battery and turn the switch on and let the ECU search for the saved TB memory then you may just get off lucky. Another Automotive scanner you can take a look is the "Autoland Scientech D91" This is the COM tool that my mechanic uses to scan for my codes. The D91 is a good idea since it is not brand specific you just need to buy the software cartridge for the brand car you drive. For example if you had a mercedes and a VW like I do you could buy the Autoland Scientech D91 and the VW cartridge and an MB cartridge and use the same scanner on both cars it may be a little more expensive than getting a VAG- COM But they operate the same, since you would get the correct interface cable and the menus are arranged the same as the VAG-COM.
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