Q5 TDI 3.0 won't start

Hi guys

I have a bad problem with my 2011 Q5 3.0 TDI with 26,000 miles. Everything works fine but engine won't start. As I turn ignition, the starter does its work but nothing happens.

I've looked through VCDS but there is absolutely no DTC error code. As battery ran out there appeared so many errors relating to Voltage appeared but I cleared them all.

Is there any common fault with these diesel engines? We do not know what to do.

- Fuel pump does work and rail have pressure.
- I can see combustion gases coming out from muffler and also from air intake.
- NO DTC error codes.

Any clue, guys?

Thank you in advance.

Did someone put gasoline in the tank?

There is no gasoline in the tank, just Diesel.

Updates:

I've checked ECU and it seems fine. Pins still look as shiny copper and there is no signs of water. Below ECU there are some relays. None of them seem to be burned or damaged. I can read any values from ECU using VCDS, but cannot make some Output tests, such as Throttle valve control unit, that says: "this output is not supported by this module", or "refused by control module".

Tried again to turn on the engine with a new battery but still the same results. It does crank but doesn't turn on. What we found strange was the following:

- We could never read electric pulses in the injectors. Maybe we are reading them the wrong way? We tried using an LED indicator in the injector connector and no results.

- Gases were coming out from the intake manifold as if they were returning from the combustion chamber.

Hope this information sounds familiar to anyone here.

Have a nice day!

When you are cranking and watching VCDS, do you see a few hundred RPM?

Hi again. Sorry about delay.

I could take a snapshot of some values while cranking the machine.



I don't understand values very well but I can imagine that injectors are actually working. Am I wrong?

Something I dont like is exhaust gases coming both from the intake system and this part.