I have a 99 audi a4 2.8 quattro

I have been driving all day then after car sat for 2 hours and i got back in started it the bat light was on and the car was not charging but it was fine all day

battery tested at 650 of 750

battery at 12.4 while not running
11.5 while running

please help cant find a clear solution

 

If your serpentine belt didn't break, or the tensioner didn't fail allowing the belt to slip on the alternator pulley, it's time for a new alternator.

 

but how is it possible to just stop working at all, wouldn't it just slowly charge less and it was because of a lose connection that it lost all charging power? im gonna go ahead and attempt to change the alternator anyways and see if it helps

 

i started it up this morning and it is charging fine... and would it be because of harsh weather that we had here yesterday? im gonna go drive around for a while and see what happens

 

it seems to stop working once in a while and there is a strange noise coming from front driver side wheel and the serpent belt seems ok

 

Front driver side wheel as in the wheel with the tire on it, or some pulley on the drivers side front of the engine. Noise from the drivers side wheel (with the tire) won't have anything to do with the alternator charging or not.

 

you were right, the noise from the right wheel was the cv axel and i replaced the alternator which fixed my charging problem but now my car has rough idle and stalls when coming to a stop

 

Probably need to realign your throttle body if you disconnected the battery.

You can do the Throttle Body Adaptation Procedure with VAG COM if you have it. Make sure you delete any error codes prior to doing the following

Turn the key on but do not start the car.

[Select]
[01 - Engine]
[Measuring Blocks - 08]
Enter Group 060 (may be Group 098 on some cable-throttle cars)
[Go!]
[Switch to basic settings]

Once you do this you will see the top right display say ADP RUN. The TB
adaptation is being done as soon as you switch to basic settings. You will see the values change and hear the TB cycle for the first few seconds then it will stop. Leave it in basic mode for about 30 seconds, then switch back to normal settings 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 think theres a way to do it without VAG COM where you open the hood and drivers door, turn the car to the run position (engine not running) and leave it in that position for 3 minutes or so, then turning the key off for 1 minute before trying to start the car. The throttle should move on its own as the ECU tries to figure out the open and closed positions of the throttlebody blades. Not completely sure of doing it this way though.

 

ill try the method with out the vag com since i dont have it, otherwise ill go to the dealer or someone who can do it for me, thanks and happy new year!

 

i think the manual method worked when i opened my hood and doors and put the key to on position i heard noise coming from the throttle body, ill report back in later to say if it was successful, thanks again.