2000 A4 1.8T Quattro Sport Avant charging problems

[AudiDoDat]

Hi all

I have the above and it has started with an intermittent charging fault, some days I get in, start her up and she is fine, no battery light on, volt gauge showing 14+, some days I get in, start her up and the battery light is on straight away and gauge showing 12v and lowers as I drive, sometimes when the light is off and charging fine I can drive 20-30+ miles and all is fine and the light doesn't come on, other times the light comes on after a few miles.

I have run her through VCDS and the only fault codes are an intermittent fault with the coolant temp sensor and no communication with the alarm horn, these have been there since I got the car.

I have removed the battery and charged it up, it is one with the "light" to show you the state of the battery, when I took it off the light was a dim green, once charged it was black, which means the battery is flat and needs charging, re-connected the battery and started her up no problem and the gauge was showing 12v+.

I have tested the voltage at the battery and the alternator, while charging and while not and I am getting the same readings as on the gauge, which I thought I would.

Does this sound like a dead battery, alternator, or something else?

Any help with this would be greatly appreciated.

Thanks in advance

ADD

Edit: This is the 180BHP model

 

[AudiDoDat]

Any idea's?

 

[aragorn]

its not a dead battery, its a fault with the alternator, or the wiring to the alternator.

 

[Sulli79]

^+1 alternator or wiring. Where abouts are you located?

 

[AudiDoDat]

Ye that's what I thought as battery is charging and holding charge fine.

I am located in Skelton, TS12. What sort of wiring is there? All I can see from the alternator is the battery wire and a small blue one that is plugged in to the back via a 2 pin plug, I believe this is the exciter wire for the volt meter, is this correct?

Should there be more wiring or is it just a case of following the wires and seeing if they are broken/corroded etc. anywhere?

I am also now having problems locating the part number for the alternator, it is a Valeo and has VW/Audi stamped on it and there is a code: L DFM, these are on the rear plastic cover.

There is a code on the plug: 4D0 971 992 and I can see some other numbers inside the cover but not all of them, these are 42292 C, will any of these numbers point to the part number?

Thanks for the replies so far

 

[AudiDoDat]

Right, I have now located the part number 06B 903 016 D and found a replacement alternator.

I have now noticed though that the car will start charging at around 4500 RPM upwards, does this point to the brushes within the alternator?

If so is it worth getting them replaced as the reconditioned one I have found is £79.00 delivered?

And does anyone know of any repair firms in the Teesside area?

Many thanks

ADD

Edit: I have also found a second hand one but it is a 120 amp model, part number: 06B 903 016 S. Could I use this one as it is only £25.00 delivered?

 

[Broken Byzan]

If i'd spotted this earlier I could have sent you a working used one. It's more likely the regualtor/brush module thta's gone

 

[AudiDoDat]

Ye that seems to be my luck at the moment!

Is it worth getting it repaired?

Cheers

ADD

 

[Broken Byzan]

i'd hazard a gues, replacement will be around the same cost as repair unless you know someone in the trade