Turbo Wastegate Malfuction?

[joshsill]

Hey all, just got an 04 audi a4 1.8t quattro 2 weeks ago and I love the car. However, I was traveling on the interstate on Friday and the CEL came on and it was a P0243 Turbo wastegate solenoid malfuction. I cleared the code at Advanced Auto and started up again and it came back. I couldn't find any troubleshooting information on this particular code so I was looking for some advice. N75 valve? Some other problem? Seems that I have very little or no boost but I don't have a gauge to confirm that. Any help would be appreciated!

Also, thanks to all for the good info I've been reading so far.

[MmmBoost]

Sounds like an N75. The likelihood of the actual wastegate failing is much less likely. Especially since n75's dying is a fairly common thing.

If the N75 valve fails it can't block the signal going to the wastegate actuator so the full pressure signal is always acting on the wastegate. It's a failsafe....the n75s fail open.

[Audi Skate Snow]

unplug the N75 and see if you get around 6-8lbs of boost.

[MmmBoost]

unplug the N75 and see if you get around 6-8lbs of boost.

Seems that I have very little or no boost but I don't have a gauge to confirm that.

It's going to be hard to sort this out without being able to see results.

[Audi Skate Snow]

shit didnt see that. ahah I swear EVERY turbo car in the world.... stock or modified should have a boost gauge. It is the best diagnostic tool there is!

[boostedAvant]

So true^

[joshsill]

I ordered a vag cable and it should be here today. Can I read or log boost with the free software version? Which is the best site to purchase a new N75 if I have to? I also see mixed reviews about which to get, revision e (stock?) or f (?) or g (performance). What would be recommended? Everything is all stock in my 1.8t and I'm not too worried about increasing HP or anything. Are there any other tests I can perform to make sure it is the N75? What voltages or resistances I should be getting across the n75 itself or the harness plug?

Thanks for all the help!

[old guy]

You won't be able to do much other than read and clear codes with the free software. If you replace the N75 go with the stock one. You can check resistance on your N75 to see if it checks out. You should be able to find a part number on your N75. If it isn't in the recommended range replace it.

058-906-283-C 20-30 ohm
058-906-283-F 25-35 ohm
034-906-283-H 25-45 ohm
034-906-283-J 20-40 ohm
034-906-283-K 20-40 ohm

[joshsill]

Great info, thanks! I'll give that a check. Also, if I check the harness plug coming from the car to make sure my wiring is OK, when should I be reading voltage? Key on, off, when starting, running?