Audi A6 Avant 2.7 TDI Quattro - Intermittent Electrics

Honest John Back Room » Technical matters
What is life like with your car? Let us know and win £500 in John Lewis vouchers | No thanks
View Threaded
Wed 25 Apr 2012 09:37
Audi A6 Avant 2.7 TDI Quattro - Intermittent Electrics - The_Man_In_Riga




I have a 2006 Audi A6 Avant 2.7 TDI Quattro and from time to time the electrics start blinking intermittently. The headlights, tail lights, instrument panel, MMI, all start flickering, but to date I have not felt that the car engine or power is affected. It happens on rare occasions and to resolve the situation I pull over, turn off the ignition and remove the key and then re-start. it seems to do the to trick, but its not a good feeling.

If it was the alternator at fault, surely the problem would be a more consistent? Is there a fuse that governs the above? The condition seems to be sensitive to the instrument warning panel indicator, as I have noticed that if the windscreen top up fluid or brake pad warning signal (need replacing soon) appears, it provokes the condition above.
Any ideas?



Edited by The_Man_In_Riga on 25/04/2012 at 09:38

Reply | Report as offensive | Link
Wed 25 Apr 2012 14:32
Audi A6 Avant 2.7 TDI Quattro - Intermittent Electrics - Peter.N.

Connect a voltmeter to your cigar lighter and watch the voltage when the fault occurs, the normal voltage with the engine running should be just over 14 volts, if it varies much from that it will likely be the alternator - or it could be that the belt is slipping.

Reply | Report as offensive | Link
Wed 25 Apr 2012 17:06
Audi A6 Avant 2.7 TDI Quattro - Intermittent Electrics - The_Man_In_Riga

Connect a voltmeter to your cigar lighter and watch the voltage when the fault occurs, the normal voltage with the engine running should be just over 14 volts, if it varies much from that it will likely be the alternator - or it could be that the belt is slipping.

Thanks for the suggestion. I will give this a go and let you know how I get on. If it is the alternator belt, I suppose if I rev the engine when the fault occurs, it should have a direct impact that I should be able to see.

Cheers.

Edited by The_Man_In_Riga on 25/04/2012 at 17:11

Reply | Report as offensive | Link
Wed 25 Apr 2012 18:25
Audi A6 Avant 2.7 TDI Quattro - Intermittent Electrics - elekie&a/c doctor

I don't think it will be the belt slipping,but it could be the alternator pulley faulty.These have an over-run pulley that can lose drive under load and cause an unstable voltage situation.hth

Reply | Report as offensive | Link
Fri 29 Jun 2012 11:22
Audi A6 Avant 2.7 TDI Quattro - Intermittent Electrics - The_Man_In_Riga

RESOLVED
I concluded that the main problem was the connection to the battery where the positive pole connection was loose.
I have now driven the car for nearly a month and all is well.

Having taken out the spare wheel housing in the boot well and releasing the battery, I was able to get at the battery and check / tighten all connections in the area.
There are quite a few connections, so it was well worth while checking and giving them all a slight tighten. The main culprit was the the main + connection which could be slightly moved by hand.

I didn't find any water problems, but it was well worth while inspecting the plenum chamber in the engine bay as it did need a clean.
Thanks for everybody's help and contributions.

For more detail see: www.vwaudiforum.co.uk/forum/showthread.php?132116-...s

Reply | Report as offensive | Link

Our honest used car pricing is a little bit different to all the others. You can get to our values through make or model - you don’t have to follow a prescribed route. Plus, it’s live, which means we can react to changes in the market quicker than any printed price guide.

Honest Used Car Prices

From which small car to buy at which price point to the best UK-built cars, our Top 10s have the lot. Click now for your shortlist.

Unsure of what to buy? Our Top 10s are here to help you....