ALTERNATOR WORKSHOP! - twice!

[Milk Corbum]

Hello,
I got the "ALTERNATOR WORKSHOP!" message on my 2002 Passat (TDI 130) two days ago followed by the battery light when the engine was running. I had a 'spare' passat with the same alternator (that was working fine) so whipped that one off and replaced the apparently bust one. Initially all was well but then after a couple of hours there was a funny noise, slight smell and then the exact same thing: "ALTERNATOR WORKSHOP!" and battery light.

If anyone can suggest any explanation for this I'd be very grateful, I'm supposed to be driving to France tonight!

[MiniMental]

A- What voltage is you battery at with engine off
B- what voltage it is at with engine running?
C-What voltage does it show when warning light is on?

[grant19841]

Yea I'm thinking like mini, possibly bad battery..
Failing that check for faulty relay.

Do a voltage check on bat first as stated above..

Good luck hope all goes well

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[Milk Corbum]

Engine off - 11.9V
Engine running - 11.45v
The battery light is on all the time. I have driven ten miles with the headlights and wipers on since the warning lights came on.

[MiniMental]

Would also be massively helpful to run a fault code scan with an obd reader or preferably VCDS whilst the light is on. May tell you exactly what it is.

Mini

[Milk Corbum]

I'll probably have to wait til Monday to do that. No-one open around here.

[MiniMental]

Not charging then. Should be above 14v when running. Try and find the fuse and check that, old alternator may have broke the fuse.

[Milk Corbum]

After the replacement alternator went in everything was fine for a while so the fuse must have been alright I think.

[grant19841]

Yea true, also how the negative battery terminal?

Give them a clean...

At idle should show reading of 14.5 so bit low there...

Put a meter in the alternator what current that reading??

I got a nice new yrs diner calling mmm lol

Good luck

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[MiniMental]

Lol. Sounds nice Grant. You should check the alternator output directly off it. Not sure if there are inline fuses off the battery leads or not... Another place to look would be the cable from the alternator to the starter. Could have eroded the insulation away and shorted against block. May be the smell you were getting?

Mini

[Milk Corbum]

Thanks folks! Will go have a dig around.

[caldirun]

Belt tensioner OK? if so maybe a short somewhere.