Intermittent ESP Warning

[Scottnybottny]

Hi all,

I still have this issues at times and through reading posts all over the place many people have known this issue to arise from faulty wiring.

Does any body have a wiring diagram or photo of the alternator wiring?

I have read that on other VAG cars there is a 2-pin signal wire from the alternator but looking under mine I have the same 2-pin connector but only one thick blue wire. Is this the case on all A8's as we use bigger/different branded alternators?

Thanks

[Architex_mA8tey]

Electrical diagrams are all on the "Current Flow - Basic Equipment" PDFs in the Tech Dump for D2's which is HERE

[Mechcanico Lee]

Does your gearbox from cold or semi warm sort of hold on to its gears and change a bit roughly , then when fully warm its all good ?

[Mechcanico Lee]

Some tests ...... from cold plug in your vcds , go to data group 007

Here's mine from coldish engine



Yes the blocks don't give any info ...... here's one I prepared earlier .....







Here's another pic 10 mins of running or thereabouts , notice oil temp !!



When oil temp reverts to a - reading this is when the auto box starts to shift a bit odd and hold gears .
By the way all the fault codes you where getting I was getting excatly the same codes .



This is pic after a bit more time running , note oil temp has reverted back to ok




Any of the technical chaps want to have a guess at where the oil temp picks its reading from ........it's NOT auto box oil temp by the way


Just for fun dontchaknow....

[Scottnybottny]

Originally Posted by Mechcanico Lee

Does your gearbox from cold or semi warm sort of hold on to its gears and change a bit roughly , then when fully warm its all good ?

Weirdly I only really notice it significantly holding on to gears when I've been driving for a while!

In the mornings I know it hold's on to gear a bit longer to warm the gearbox up asap and the shifts are smooth as you would expect. My journey proceeds for about 10mins of A-roads doing 40-60mph with a few sets of traffic lights and island's on the way, again all is smooth with the gear box. Always around 5-6mins after starting the car I get the ESP light flash on and off 3-4 time before it becomes a permanent light. After the A-roads I do 30miles on the motorway so it's all good and toasty. As I leave the motorway and again encounter smaller roads it begins holding on to gears, second up to third is the most noticeable and when it does change it slams you in the back like being rear ended by another car.

If I pull over after 10mins or so, restart the car the ESP light usually stays off for the remainder of my journey.

I will try to log group 7 like you say and see if we get matching results.

Have you had any success in finding the culprit part? or still an on going issue for you too?

[Mechcanico Lee]

Oh yes I did find the fault , just look at that block 007 first , especially when you feel the gears holding and bumping in , just to see if the value goes mad or minus temp readings .
Saves me finding all the info and going up the wrong path with the diag if it does not show any problems on that temp reading .

[Scottnybottny]

Hi Lee,

I have finally found the time to do the test from cold as you suggested and I am happy to conform that the oil temp reading acts much the same as yours did and coincides with the ESP light illumination.

As you can see in the attached images the started from cold and all seems fine. After a few minutes of running the temperature climbs and sits at a sensible level.

After approx 10 minutes of running the temperature rises to 'High Temp' before illuminating the ESP light and suddenly dropping to the negative number as you suggested.

I fast idled the engine from then and the ESP light went out and the temperature rose to a reasonable value again.

Please can you provide me details on the part(s) you replaced to rectify this.

Thank you for all of your help thus far

[Mechcanico Lee]

Scott , yes that's what I suspected , you have slightly different to mine but you can be sure this will be your fault .....high oil temp ( sensor short to positive ) Low oil temps ( sensor open circuit )

Now I knew oil temp was measured from the oil temp sensor in the sump so I replaced that ( £70 genuine part ) fault still excatly the same after this .....DOH!!!


I started looking all over the engine to find another oil temp sensor and spotted it luckily ........




Look down below the air con pump ......









See the chrome pipe sticking out with a banjo bolt going front to back of the engine .






Can you just see the shiny new sensor with the wiring with the rubber sleeve it's a bit hard to see , there is two on the machined block on the pipe , one over to the passenger is oil temp , the one over to the drivers side is oil pressure





Here's the parts diagram , can you see the mounting bolt number 22 , that's the machined block just above , can you see how it does not show either the oil temp or oil pressure switches in the pipe ..... the parts man said they only showed as a foot note on the discriptions part of the page , I had to take the switch out and get the part number off it , it's ........

Sender 059919563 .... £18






With a long 3/8 extension with a universal joint and deep socket you can get it ...bit of a fiddle but done in 10 mins no worrys .



Look back at the very first posts where I said " I'm suspicious of the oil temp codes " ........I was correct eh ??
I've not got where I am today ........scoff scoff ......pist n broke ......


Hope this helps you and others

[Scottnybottny]

Thank you!

I'll get the part ordered on Monday, for ASAP and let you know how it goes.

Like you say I've never come across it in any part diagrams, haven't seen a thread where the switch has been mentioned for any ESP related issues. Would never have found it without you.

Thanks again

[Scottnybottny]

Got the sender from Audi late last week and got round to fitting it yesterday.

A little fiddly to get to but easily do-able in 10mins as suggested. You do however need a really deep 19mm socket to house the entire plastic connector inside the socket (30mm).

All good so far, did a few trips yesterday when the light would usually illuminate but no sign of it as yet. I will continue to monitor throughout the week and see if the clunky shifts are also cured in the usual circumstances.

Thanks once again