s6 broken down starts then stops

[220bhp]

My s6 broke down today, Fuel was low so I thought hat was it as it stopped then after a few seconds it started again.
I managed to get to a garage and filled it up. car started but stopped after half a mile right on a roundabout upsetting quite a few people in the process managed to get it started again and struggled too my mates garage ,
Cleaned the fuel filter etc., loads of pressure more than I was expecting.
On the test run it died again like there was no spark.
We took the coil cover of and put a spark plug in one of the coil boots but there is no spark .
if it isn't fuel what would cause this issue of intermittent running .
any help would be appreciated.

[220bhp]

I have not read the codes as this car is historically difficult to extract codes from for some reason.
There are two connectors under the bonnet in the black fuse box , One black and one white we tried to connect vagcom but no go
Maybe it will be possible to blink the codes. if I could remember. its a little different to my 3b.

[Dynasty]

Regarding reading codes via the 2x2 - ports, make sure that there is power in the black connector:

http://www.ross-tech.com/vag-com/2x2.html

[twoqu]

Difficult to take a stab at without any supporting evidence such as a code but a falling G40 could be responsible:

http://forums.quattroworld.com/s4s6/msgs/139944.phtml

You could really do with trying to solve the non communication issue with the ecu. The black connector should have earth and power and the white are the K and L connection back to the ecu. I seem to remember there are connectors in the loom somewhere which might have been disturbed. Of course it might be something else such as a stuck K line or aftermarket radio issue. I think Audi recommend removing all the diagnostic rings from the post where they meet the 2X2 loom and replacing them one by one and seing whether the ecu responds then. So effectively you would have the 2X2 connected to one ringlet if you see what I mean until you find the engine ecu circuit. Perhaps we can eliminate some by identifying the ecu from the wire colours!

Good luck!

[UrS4boy]

You might want to read these:

Pulling Codes: https://www.s2forum.com/forum/techni...ease-learn-how

J17 Fuel Pump Relay: http://forums.quattroworld.com/s4s6/msgs/22583.phtml

G40 Cam Position Sensor: http://forums.quattroworld.com/s4s6/msgs/22580.phtml

[220bhp]

Finally pulled the codes after many failed attempts. It would not read until I put the engine code in as ADU RS2 ,very strange that.
I got the four codes. Three for the hall sender 00515 and one for the lambda .
Cleared the codes ,and the car started first time. ran it up to temperature and drove it for several miles with no issues but it did cut when I pulled over to let a car by, although it started straight away.
On checking there where no codes other than the crankshaft sensor which I believe comes up every time when the engine is not running.
ordered a new bosch sensor to fit on Monday ,so fingers crossed . Thanks everyone for all the help.

[RichLV]

You might want to have a look at that Hall Sender. If it fails while you're on the go, once stalled or stopped you won't start the car again. BTDT.

Reading only when picking ADU might be because the ECU might not be stock. Is it modded?

[Bosscat]

Just a blind corner - do not know if the S6 has the same double bulkhead as the A4 but on both my previous A4 TDI and my RS4 the bulkhead drain blocked
Went through two dealers workshops before I deciphered the problem myself - drian outlet had blocked whoosing water obout electics and ECU ???
Just a wild one but easy to check and eliminate.

[220bhp]

Not good news. I thought we had fixed the car by fitting the new g40 hall sender, but she let down again . Stopped after a couple of miles , wait ten minutes and it started again . it done this five times before I could get the car home. codes came up with hall sender again short to ground .
I have discovered that relay 205 has corroded badly ,and looks like its been arcing.
Not sure but I think its the fuel pump relay.
I have ordered a replacement which I hope will sort the problem. if not I am stumped., as my s2 has just let me down as well. now about to start another tread for that.

[twoqu]

Might be a good idea to inspect as much as the wiring for the hall sender in the engine bay to see if its worn through anywhere and bare!

[220bhp]

Does the wiring go back from the front connector straight to the ECU. or is there another connector on the bulkhead then on to the ECU ?.

[twoqu]

Pretty sure its straight back so it could have a hidden problem somewhere along its length. Short to earth implies its making contact with metal somewhere.

[Dynasty]

Check the crank sensor (speed sensor). I had same symptoms on a Audi A6 2.4, replaced the crank sensor -> problem solved...

[UrS4boy]

Does the wiring go back from the front connector straight to the ECU. or is there another connector on the bulkhead then on to the ECU ?.

Straight back (into the engine harness and off to the ECU)

http://forums.quattroworld.com/s4s6/msgs/22580.phtml

[220bhp]

Found the 205 relay for the fuel pump was badly corroded , and appeared to how signs of arcing .
I have just replaced it with a new one , and the car ran for an hour without issue.
I f this was the issue could it be possible that the hall sensor code could be triggered if the relay cuts the fuel.