S4 won't start

[JohnP68]

Tried to start my B6 S4 today, but when I turn the key the engine doesn't turn over and won't start. Electrics seem to be working - including lights - so there is at least some battery power. If flat battery I would have thought the engine would at least turn over a little, but it doesn't move at all. There's not even any sound from the starter motor - no clicking even. Car was working fine a couple of days ago. I've tried the spare key too.

I've got the error codes off using vag.com and there are about half a dozen "supply voltage too low" errors - no other errors though. I've put a multimeter across the battery terminals and the voltage is only about 10 volts.

Anyone got any ideas what the cause could be please, before I get someone out tomorrow to look at it. Cheers.

Edited by JohnP68 on Sunday 26th April 20:15

[pad58]

new battery

[Seez]

yep, new battery needed, there is enough to power electricals to some degree, but not start the car, you need to replace the battery before trying anything else... Aa will confirm it if you are a member.

[Nobody You Know]

It may not be battery.

My B6 S4 does this now and again, full ignition turn on but won't start. Try it a couple more times or leave it ten minutes and it is fine.

It's something I need Audi to look at as although it doesn't happen very often it is a pain in the ass.

Perhaps worn ignition barrell???

When I bought the car Audi tryied to fob me off with a duff battery but even that when nearly dead would still try and turn the engine and make a noise.

[TiggerS400]

I had this with my own B6 S4 last year - it's the starter motor that's causing the problem. Apparently they get cooked by the exhausts and eventually just work intermitently.

Surprisingly, it's not that expensive to get fixed as Audi do the starter motors on exchange (think mine was about £110?) - just make sure that when the battery is reconnected it's done firmly - mine wasn't and I then had to go an get all the dash computer reset at more cost.

[JohnP68]

Thanks for all your suggestions. AA man came today and he said the battery was flat. Re-charged and car started fine. Apparently the battery seems ok and is taking a good charge. Mystery is why it went flat in the first place. He said to keep an eye on it, as there may be a leak of current somewhere. Fingers crossed!

[Fort Jefferson]

JohnP68 said:

Thanks for all your suggestions. AA man came today and he said the battery was flat. Re-charged and car started fine. Apparently the battery seems ok and is taking a good charge. Mystery is why it went flat in the first place. He said to keep an eye on it, as there may be a leak of current somewhere. Fingers crossed!

I had this with mine a few times and it was two years before it gave up all together. If I were you I'd change it now or it will give up when it matters.

[brisel]

Good call - cold weather will soon let you know if the battery is on its way out.

You don't need to buy a genuine one - Audi will only rip you off. Do make sure that an non-genuine one has the same cranking amps capacity though.