AUQ Code 17705 (but can't find the problem)

[MoMartin]

Hi all, I always remember how helpful this forum used to be for when I had my AGU, I've now got an Octavia VRS AUQ, but since having it, it's had many boost problems, the latest being limp mode after coming off boost.

Anyway, I've scanned it for codes and it's thrown up the code -
17705/P1297/004759 - Pressure Drop between Turbo and Throttle Valve (check D.V.!)

I've recently replaced the diverter valve for a Forge 008 with the green spring, which hasn't fixed things. I've also replaced a few t bolt clamps which were slightly out of shape and have cleaned the throttle body, which were also to no avail.

So I've now hit a dead end / I've run out of ideas, so does anyone else have any ideas?

Thanks in advance

[Wazzzer]

It can be a gremlin in the EC's coding, but only go down this avenue if EVERYTHING possible has been checked. You could always give R-Tech a bell about this as they have had a lot of dealings with it

[Dalo Harkin]

Have you tried another spring?
have you serviced the DV

My bet would still be a slightly leaking pipe

[MoMartin]

I was going to leave r-tech until the last resort (I want to put a hybrid turbo on first!)

I've tried both the yellow and green spring and both do the same, and the dv was bought brand new, so I cant see why it should need servicing.

How much of a difference could a small leak make?

Thanks

[Wazzzer]

the AUQ will try to reach the requested boost even if you have a leak so it will effectively over boost your turbo to compensate for the leak hence your fault code

[MoMartin]

Okay thanks I get you, I'll have to continue trying to troubleshoot it then

[OSR]

I had this code for years on my AUM. Ended doing the following (some indirectly related to the issue but at least ruled them out);

New DV
Catch can install
N249 delete and tidy up of vacuum hoses etc.
Full set of boost hoses
New N75 valve
Throttle body clean

I still used to get the code and could feel it overboosting and even going into limp mode sometimes. Ended up finally getting rid of the code when I fitted my FMIC and associated pipework which leads me to believe it was a leak around the intercooler/pancake pipe connections in the end.

It is indeed a gremlin to track down, my only suggestion is to go through the motions, most of the above things to check/replace with the exception of the FMIC 

[MoMartin]

Thanks, I've now invested in to making my own boost leak tester (Garage wanted £70!!!) so hopefully come this time next week I should have it sorted.