kozlovee

LOG AUDI S8 - VCDS Scan

kozlovee

VCDS LOG

MP4.2+6.0

Unfortunately it is two step and this scan has no obvious pointers. First you have to clear all codes if issue has not arisen since prior scan and clear. But then the issue needs to be re created or left to occur again.

In my experience/judgment, this car was very recently cleared, perhaps today just before the scan.
FWIW, this is also the same evidence in a smog test when someone has just cleared codes--or a dishonest car seller trying to get rid of a check engine light. California is rigorous as an example, and require all 8 be at "ready" states. Some other U.S. states with smog tests let some go by.

See: Ross-Tech: VCDS Tour: Readiness Also see screen shot below with what each one is. Ignore where it says in that screen shot "no diagnostic yet" or "not available". It was an old document, and they are all enabled on any recent gas Audi. Net, you need to drive it a few cycles from cold to warm/hot to cold motor temp to see if codes reset or something goes wrong. Once it goes wrong, get scanned again.

If the ECU ends up coming back without codes (like it is now) but readiness codes have reset correctly, I would go back to the crankshaft position sensor I mentioned in an early reply. About the only thing I know that folks have confirmed can fail erratically and still leave no codes. It is a guess, but a lot less expensive and work than many others have been that dealer already tried. Fuel injection, fuel pumps, vacuum and other ignition issues should leave a trail of fault codes in general.

kozlovee

Hello ! i have just made a new VCDS Log , because in this morning the car start just fine , i have drove 20 km , after that i have turn of the engine , and after 1 hour , when i have tried to start the engine , it did not start until i have pressed the acceleration pedal ... I have attached the LOG VCDS , and also i video how exactly is happening.
Have o good day

MP4.2+6.0

Sorry, I can't open the video with a Mac laptop. While I doubt it is critical for the starting issue, you can see the codes pointing at the exhaust flap. That may be causing the rich code in some way if the issue is on the same side of motor, but it is hard to be sure. The exhaust flap should be checked--whether just jammed, needs a spray of some penetrating oil, or other things. But it doesn't explain the not starting and being tied to having to move gas pedal. Not starting in that way raises questions about gas pedal itself, but there are no obvious relevant codes. Probably what the dealer has struggled with too.

Suggestion to diagnose further: get a can of starting spray (Ether). Try using that by spraying into both intake areas (both sides) when car is not starting with no gas pedal movement. Spray 1-2 seconds each side and then quickly try to start. Do not move pedal while trying it. If car starts after spraying it, it suggests problem is on the fuel side. If car does not start, it suggests problem is on the ignition side as far as remaining areas to consider.

bryan100030

My Audi A6 2006 3.2L Quattro just had the Fuel filter and oil filter changed. Now she wont start when engine is warm/hot, and will DIE, like at a stop light. Could this be a Camshaft Speed Sensor issue?? Any help would be AWESOME!!! Thank you so much!

audisession

I had this issue on my former Porsche 911. Exact same symptoms.
I replaced the fuel pressure sensor and it was resolved.

kozlovee

Hello everyone !! PROBLEM SOLVED
I just recheck the high pressure fuel pumps , and one of them was broken ... it was escaping pressure , i have changed it again , and the car runs great now !!

Thanks for help !!

Have o good day

Jack88

Glad it's solved!

slickNSX

Has the fix been permanent? Can you help me with part numbers on which pump they replaced, I am having the same issue on 2013 S8 D4, I have no check engine codes, and hard/long starts when car has been run and parked for 20mins or more, cold starts are perfect. Help will be appreciated.