Full battery won't start. A6 c6 f4 allroad 3lt

[grim]

Hi all

So iv had a problem with starting the the car. Fob works to open the car the radio and internal lights come on. But wen I place the key in and turn it 1 click right there is nothing on the dash. The car clunk's and release the steering lock fine but then that's it. I carnt get the old reader to connect to check and codes. The battery is good I charged it for 24 hrs and was registered 12v. First thought was starter motor but if this was the case wouldn't the car still turn on and then not start. Any help would be appreciated.

Thanks Grant 

[Magnet]

Thanks Grant,

If you are judging the battery’s efficiency as being ‘good’ by using a simple multi meter, then you are barking up the wrong tree. 
In any case, a reading of only 12v after a 24 hour charge is too low. 

Regards,

Gareth. 

[grim]

Do you think it could be the battery still ?

The health bubble is also green.

Edited June 12 by grim

[Magnet]

The first thing to eliminate/incriminate is the battery. Halfords stores or probably your local motor factors can test its efficiency - under load.
Please let us know how you get on. If you need to replace the battery, then buy once and wisely.
The forum can advise you on this. 

[Marcin Z]

Would it make sense to try and start it with jump leads? If it starts then you know starter is ok, and maybe the issue lies with the battery. In any case you will probably need to do this if you are planning to take it to a garage to get the battery tested. 

[grim]

Ok so far. Iv test every fuse including both sets under the bonnet.  Popped over seen garage he is of the similar opinion and said to test earthing. Iv test the earthing by jump lead from -at battery to engine block. I've tried to jump start the car the doner car wasn't very big tho. Iv ordered a large capacity jump pack and a newer charger. If that don't work I'll have to push it upto the garage. I've seen that you can manually get the car out off park. But that won't be till next week. Will keep feed upto date with progress.

Thanks Grant 

[cliffcoggin]

Grant.

Did the engine turn over when you tried to jump start it?

Rather than push the car to a garage why not call out a mobile mechanic and get him to test the battery, which is the most likely problem? 12 volts is too low for a battery in good condition.

[grim]

So took a battery reading 12.6v then 12.3 with the ignition on. Jump start from donor car did not  work/change anything in the dash.

Edited June 13 by grim

[cliffcoggin]

That does not answer the question of whether the jump start cranked the engine.

[grim]

Sorry. No it did not crank the engine 

[Magnet]

Hello Grant,

Meaningful information and the results of advised tests are dribbling through slowly, but dribbling they are. 
Important :-

Is this car a manual or an automatic? 
How did you measure the latest battery voltage?
Was the engine on the jump start donor car ( what was it?) running at about 2,000 rpm when you attempted to start yours with it. 
Regards,

Gareth.

[Marcin Z]

Unless I am missing something surely connecting the jump leads would at least illuminate the dash with ignition switched on, even if it did not manage to start the engine. I think maybe this is a bit more than a battery issue. Just my thoughts. 

[cliffcoggin]

5 minutes ago, Marcin Z said:

Unless I am missing something surely connecting the jump leads would at least illuminate the dash with ignition switched on, even if it did not manage to start the engine. 

Not necessarily. Instrument clusters are known to suffer failures which may be unrelated to the starting fault, hence my question about cranking from a jump start, and emphasises Magnet's request for detailed information.

So far I think we are left with many possibilties that include: starter motor/wiring, ECM fault, defective battery.

[Magnet]

Thanks Marcin,

You may well be right, but it is only an assumption that it is ‘more than the battery’ until the battery has first been properly tested and eliminated as a culprit. This is No.1 test of a series of tests, but we don’t seem to be getting too far. Saying it as I see it, so far, it’s a bit like extracting a sore tooth? 

[grim]

So it's a 07 c6 f4 allroad auto. Was hoping that with the attempted jump like you said would at least get the instrument cluster on as it was only a 2lt car the revs were hight but carnt guarantee they were over as i was in the car

 

. But it did not. Using a multi meter to test voltage at battery and in engine compartment also from battery to the engine compartment. Iv checked continuity of the earthing from battery to engine block. I checked voltage from battery to engine block and it at 12.6. I tried disconnected the battery module that didn't change anything. Car has been on charge throughout but disconnected for any test then placed bk on charge. Whilst its on charge its only reading 12.7v don't no if that's relevant but got a bigger charger coming 2mrow. I turned the radio off 

Edited June 13 by grim

[grim]

I have another older 110amp battery. Would it be worth charging that and trying that in its place

[Magnet]

You are wasting your money Grant with getting a bigger charger - why? 
Trying an old battery??? 
I think I’ll dip out of this one until you report back with the official test results on the battery using meaningful equipment. This has to be the first test. 

[cliffcoggin]

10 minutes ago, grim said:

I have another older 110amp battery. Would it be worth charging that and trying that in its place

Only it it is any good, and you won't know that unless you get it tested, in which case you might as well get the fitted battery tested. Let me emphasise that simple voltage readings from a multimeter will not tell you if the battery is in good condition. A battery can show over 12 volts and yet have internal faults that can interfere with the delicate electronics of the car causing a variety of seemingly unrelated symptoms, one of those symptoms being a lack of error codes on low quality OBD readers.

Until you get the battery tested we can not eliminate it as the cause of the starting problem.

[grim]

So mechanical has been over and he is stumped battery ect is all good his advice was its software or electrical as his cpu is good but not perfect. It's recently had a software update at audi wen it went in for a recall. Could this be a problem? 

[cliffcoggin]

This is the first you have mentioned of a software update at Audi. What equipment in particular was updated and why? Unless you give us the whole story we really can't help you.

[grim]

Ok. So audi recall was for airbag they also changed the inlet manifold and did a software update but as that was some months ago. They didn't say why and what it was for. Gonna try getting hold of a full vcds reader hoping that will have better chance in getting a code up than the garage.