I also posted this thread in the S Section of the forums, but didnt get any response, so if im not allowed to post the same thread in two forums please delete it from the S Section. Just for the record the car is a 01.5 s4 6spd

Well Yesterday I had two new tires put on my car. After i picked it up from the place my gas light went on...so i stopped at the nearest sunoco and filled up.
I drove about 3 miles and shut the car off. 6 hours later i started the car up to go home. About a mile later i thew a CEL. I ran back to the shop scanned it with the snap-on scanner and got code 17883: Evap System Malfunction: No Signal. I figured i might have forgot to tigten my gas cap, so i went back.. Tightened it 3 clicks, cleared the code and went home. After i started the car again and drove a block or two i threw the same code again.
Now from what i have found from searching normally the code is something a little different and it would say Small Leak, or Large Leak. However, i have neither of those. I have NO SIGNAL, which isnt that common from what i gather.
So after much reading and all, i thought maybe it was the N80 valve. The n80 valve stays closed when the ignition is off holding all the vapors and pressure toward the rear of the car. When you start the car the Valve opens releasing the vapor/vacuum into the whole system.
So i figured the n80 could be the culpurit because if the valve is getting stuck closed and not releasing the pressure when i start the car...Then the Evap Pump would not recieve any signal, hence the NO SIGNAL code.
Today i troubleshooted the n80 valve and i think its fine. I ran a test through the snap-on scanner which opens and closes the valve constantly for 30 seconds. If i applied vacuum on the valve with a mityvac, everytime the valve would click i'd lose a little vacuum. Not to mention if you put your hand on it you can feel the selenoid clikcing inside. So i figured the valve is operating correctly, or opening and closing atleast. Could it still have a possible malfunction when the audi evap system calls upon it? Sure, but i think its pretty unlikely.
So the next culpurit which i didnt get to yet is the Evap pump in the driver side wheel well. Im going to pull my tire off today or tomrorow to a get look in there at the electrical connectors and the pump. Im guessing if the part of the pump failed that detects the Vacuum, that could be causing it also. So i may try replacing the pump on monday.
Im just making this post to see if anyone else has had this same exact code...and what they did to correct it. Also to see if anyone has any other thoughts on how to correct the problem.
Any help is greatly appreciated.
Thanks in advance
John

 

According to Bentley:
P1475 17883 EVAP Emission Contr.LDP Circ Malfunction/Signal Circ.Open
Check the leak detection pump (LDP). Here is a screenshot of the resistance values that are normal.



[IMG]local://upfiles/18457/1053B39F79284520AEDC7F2D7B744AF2.gif[/IMG]

 

Thanks alot, im going to check that as soon as possible.

 

Signal Circuit Open

Open circuit, could be a disconnected wire.

 

Yeah i was thinking that as well. The all data troubleshooter...which is something like bentley says one of the corrective actions is check the wires. So i will check that as well.
Ill check the wires and check the Continuity of the connectors on the pump to make sure the readings are right.
Im about to go check it now
THanks
John

 

Well I checked the values on the pump like Bentley shows. Pin 1+3 is 680 and pin 2+3 is 15
The only problem i had was that Bentley shows two diagrams according to two different manufacturer dates? but i didnt understand them. I couldnt match it up with the manufacturer date on my car? It has two sets of values for the same date? So im assuming 15 is an acceptable number on pins 2+3.

I ruled out the pump and i ruled out the n80 Valve? which are like the only two things that it can be according to this code, other than a leak. But when theres a leak its a different code. I played with the wiring a little bit while i had the pump out...made sure everything was tight? I'll try again.
I normally dont mind trouble shooting a cel, but when its the evap system its a nightmare. I'm probably going to have to buy a vagcom for this one.

Any other ideas would be greatly appreciated.
Is there a fuse that is directly related to the pump?
The only thing i did that could have possibly messed with the system was fill my car up without turning it off? But even after that i made sure the cap was tight and reset the ecu and it came back. And i've filled my car before while running without having any issues.
Thanks
John

 

The only other thing i cant hink of is...if the Leak Detection Pump is electrically functioning correctly.. hence the correct resistancy readings...but mechanically is malfunctioning.
I'll have to get the car up on the lift at my shop tomorrow and test it with a mityvac and all. I might even just try putting a new one in.. My friend has got a bunch of 2.7t audis in his junk yard..he'd probably give me the pump.
If that doesnt work i'll just have to buy a vag com