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View Full Version : HELP 98 2.8 v6 AUDI p0441 Vacuum runs all night with key off kills battery.



casey4480
10-29-2011, 04:16 PM
I have cold air intake installed on my car the hose that hooks underneath the STOCK air box sounds like a vacuum cleaner, i have a small air filter clamped over the opening (not intake air filter). Its throwing an evap code p0441 purge flow fault. My main question is why is it running self diagnostic checks all night (vacuum cleaner sound cycling on and off) with the key off, it is causing my battery to die. I searched other forums tryin to find a similar problem but havent came across any i would appreciate to hear anyones ideas or advise on my problem for now i am goin to disconnect the battery everytime i stop.. <<<please help>>>

FNK
10-29-2011, 07:43 PM
Pull the fuse of the Secondary air pump (SAI) in the meantime.

anmagro
10-29-2011, 08:35 PM
I did the same thing on the same car and i never had this problem. Maby clear the code after letting the batt disconnected for a while? taking out the fuse to your SAI may just be your end all solution. Try putting a higherflow filter on it?

walky_talky20
10-29-2011, 10:10 PM
So the main question here is: how is the SAI pump running without the key? Let's investigate:

- The pump gets constant ground from the chassis via a ground connection in the engine compartment. So the question becomes "how is it getting power (12V+)?

- The SAI relay provides 12V+ to the SAI pump. The relay has constant battery voltage available (via the SAI Fuse) which is applied to the SAI pump whenever the relay is closed. So as long as no harness modifications have been made, this narrows our question even further to "What is making the SAI relay close?".

- The SAI relay gets a ground signal from the ECU to close. While it is unlikely the ECU could even provide this signal without key-on power, let's assume for a moment that it can (or has failed such that it is doing exactly this). Would that be enough for the relay to close and kick on the pump? Nope. The *other* side of the relay coil requires power (12V+) for this to happen. It just so happens that that power is provided by the Fuel Pump relay. So closing of the SAI relay first requires closing of the Fuel Pump relay.

- Seeing as the fuel pump relay directly requires a key in the ignition to close (as well as command from the ECU), AND that no mention of the Fuel Pump randomly running without the key is mentioned, we can assume that is not happening.

- So where does this leave us? Seeing as there is no signals to close the SAI relay, but it would seem as though it is indeed, closing anyway, I would assume this to be a failure of the SAI relay itself: the relay is sticking closed. I feel that is the most likely explanation and would proceed to verify that conclusion.

casey4480
10-30-2011, 06:04 PM
I understand the concept to unplug the sai pump but i had no fuse that was the secondary air intake??? I am researching and looking for sai relay/solenoids. I just want my AUDI BACK haha!!

walky_talky20
10-30-2011, 07:09 PM
If you don't know, just ask.

The relay for the SAI pump is in the ECU plenum box, right next to the ECU. It is the center relay, and the SAI fuse is right next to that. It is the huge 50 Amp fuse. It is a little bit of doing to get into the ECU box, so you could also just unplug the connector right at the pump itself in the meantime.

mmcl43
01-25-2013, 09:48 AM
If you don't know, just ask.

The relay for the SAI pump is in the ECU plenum box, right next to the ECU. It is the center relay, and the SAI fuse is right next to that. It is the huge 50 Amp fuse. It is a little bit of doing to get into the ECU box, so you could also just unplug the connector right at the pump itself in the meantime.

[:(][:(][:(][:(] What would be easier to do 1n 19 degree weather here in Penna ---- unplug the connector from the pump or go for the 50amp fuse ? ( for a 57 year young fella ) 1999 a4 2.8 quattro Would it affect performance at all ???

mmcl43
01-25-2013, 09:49 AM
[:(][:(][:(][:(] What would be easier to do 1n 19 degree weather here in Penna ---- unplug the connector from the pump or go for the 50amp fuse ? ( for a 57 year young fella ) 1999 a4 2.8 quattro Will either affect how the car runs ?????