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Ok so I got the wastegate rod is moving while reving . I ...


Ok so I got the wastegate rod is moving while reving . I have no codes showing . The scanner I have is the shop scanner it’s pretty intricate. I can test the diverter valve thru it and the n75 valve . I replaced the boost pressure...

Ok so I got the wastegate rod is moving while reving . I have no codes showing . The scanner I have is the shop scanner it’s pretty intricate. I can test the diverter valve thru it and the n75 valve . I replaced the boost pressure sensor and the n75 . When I go to test the n75 valve it says negative response . The car has jerky acceleration it feels like the boost is working on and off . But at wot it’s like there is no boost . I’m not sure what to check next . I can’t get ahold of a vagcom at this moment . But this scanner shows a lot but don’t know what I should be looking for or why the n75 is not working during the test . Any ideas

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Responses

Automotive Expert
Hello, this is Jason again, and thanks for requesting me. Unfortunately, with all sorts of different levels of scan tools, I can usually only offer assistance using VCDS. If your tool will show N75 duty cycle, ECU requested turbo boost and actual turbo boost on the same screen, then we may be able to go forward. I'm not exactly sure what an N75 negative response is, since it's actuation is measured in duty cycle percentage. Also, with the symptoms you're describing, if you've put more than 5 miles test driving there will be fault codes present, so I'm really questioning the ability of the tool you're using. Also, just to drive the point home further, the VCDS cable is $199, and at this point would have been cheaper than or roughly equal to the cost of the parts tried so far. Link: https://store.ross-tech.com/shop/vchv2\_ent/

take it to Audi
Automotive Expert
So, this situation definitely requires the right tool to diagnose and ultimately repair. Let's use a simple example. You've got a 13mm bolt to remove from the car. You only have one wrench in your toolbox, and it's a 17mm. Would you be able to remove the bolt? Nope, you'd go out to the store and get a 13mm wrench. This is a similar situation, but obviously the cost is much greater. In 1996, when OBDII came out, scan tools became just as important as a good socket set, and not all scan tools are created equal. This is a case where you need the right tool for the job. And I offered a link where you can buy that tool if you would like. I have no affiliation with them, other than using this exact tool since 1998 Or bring it to a good Audi independent or dealer if you'd like. Completely your call.

I appreciate your help . Car seems to be back to normal now .I did order vcds. I can hear it spooling like it should and it’s pulling again. Maybe the ecu needed to adjust idk .
Automotive Expert
Ok, good to hear that you ordered that. It will definitely help in the future. Please reach out with any further questions, as I'm very familiar with the car and the scan tool

Will do I am still having some issues but will def wait until I get the vcds . Little acceleration jerkiness
Automotive Expert
Ok, and when you get that, I can help with certain data blocks that you can monitor to try to nail this down

Good deal .
Automotive Expert
Thanks

How do I actually test who’s pressure no he can be on VCDS
Automotive Expert
Can you please retype that question, as I don't know what you're asking

Boost pressure how do I actually test it with this system
Automotive Expert
Select control module 01-engine adv measuring values type boost in the blank field. Look for lines that say "boost pressure specified" and "boost pressure actual", or wording similar to that. Check both boxes, test drive car with passenger watching the screen to monitor each. Let me know the peak of each You can graph it also, but that's a bit more complicated to explain, but easy to see when you get to that screen

There is charge pressure but not boost pressureI graft the high pressure fuel pump and I tried to graph the charge pressure but I didn’t see it on the graph
Automotive Expert
like I mentioned, similar wording. I don't have VCDS in front of me so don't know the exact wording from memory.

Ok I’ll try the charge pressure
Automotive Expert
sounds good.

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