Replaced my battery and now when I start it idles fine, drives fine, but everytime I brake to a stop sign or stoplight, the car just dies right when coming to a stop. the voltage level bounces and it just dies. Kinda scary when in traffic so I'm not driving till I figure out what is going on. Any ideas?

 

Disconnecting the battery can throw off the adaptation of a drive-by-wire throttle body. Rule out automatic transmission issues by putting it in neutral as you come to a stop, but I suspect your butterfly valve is closing too far. It would not hurt to remove the throttle body and give it a good cleaning, or at least to pull the air intake hose and spray some cleaner directly into the butterfly valve area and pivots.

The throttle body should have readjusted/relearned the butterfly closure, but somehow it is failing to do so.

 

Also check that your brake booster or line to it is not leaking maybe by plugging it and see if that makes a difference.

Dealer says my brake booster diaphram is bad but I have never seen one of those fail in 30 years of working on cars. Although, leave it to Audi have one fail on a 10 yr old car.

 

Hi dear today i read this topic it's really nice and informative i want to say that i made a little go kart thing (nno engine) AND I WNNT something that can stop it fairly quik. like pressing something against the wheels to make it slow or stop immediattly....

 

Do a throttle body adaptation and you'll be good to go.

 

Our B6 A4's are KWP-2089 correct? If so, this is what I saw regarding TBA:

Procedure for performing a Throttle Body Alignment on DBW Cars using KWP-2089:
(Check to see if the engine speaks KWP- 2089 by looking in the top left of the Open Controller Screen Some examples of KWP-2089 engine controllers are 2002+ Audi A4, 2002+ VW Passat, and Touareg)

Turn the key on but do not start the car.

[Select]
[01 - Engine]
[Basic Settings - 04]
Group 060
[Go!]
It should say "Basic Settings: OFF" on the top of your screen.
Click [ON/OFF/Next] to turn on Basic Settings.
It should now say "Basic Settings: ON" on the top of your screen.
Once you do this you will see the top right display say ADP RUN. The TB adaptation is being done as soon as you switched basic settings on. You will see the values change and hear the TB cycle for the first few seconds then it will stop. Leave it in Basic Settings for about 30 seconds.
Click [ON/OFF/Next] to turn off Basic Settings.
It should now say "Basic Settings: OFF" on the top of your screen
Click the [Done, Go Back] button and you're all set.

Be sure not to touch the accelerator and make sure the engine is NOT running when you do this!
______
I was going how to ask howto do it but then googled it so might as well paste it here.

 

I have a 1998 B5(?) A4 2.8 30 valve Quattro automatic. The car was alway stalling and needed cam sensors. The prior owner put in a substandard battery.
I replaced the cam sensors, installed the proper battery, even replaced the plugs with OEM copper core duals (there were platinum 4303's and I read this was NOT the right plug application) and noticed the old plugs were totally black carbonized.
Paperwork from the dealer to the prior owner said "TB needs replacing".
However, this car always starts up fine and then after a few minutes (either sitting idling or driving) the TB does some change and the idle drops.
From that point it will always drop down to 300 or 200 RPM with foot off the accelerator and stall. After the repairs, the codes cleared, and the check engine light off, a friend said to take it out and run it so the ECU could reset itself. It has not. The car passed CA smog fine, and still wants to stall. The check engine light has NOT come back on while driving. Suggestions?