secondary air pump / smog pump / 2001 VW Passat 1.8T / 4 cylinder / error code P0411

Sebastian,

I believe the fuse is located in the black box mounted on the firewall next to the brake fluid reservoir.

Unless you have a cracked hose (either a vacuum control hose, or the actual rigid plastic hosing from the pump to the valve) or some other fault, then the water in the pump is due to your combination valve failing (open). The valve is only supposed to be open when the air pump is running. Lots of these valves fail, and they don't close all of the way.

When they stay open (or "leak), then exhaust flows down into and through the sec. air pump. The pump body cools the exhaust and the moisture condenses out of it. The water builds up and corrodes the pump over time. In freezing temperatures,, the water freezing will damage the pump even more quickly.

So, replace your pump, and the fuse for it. But also carefully test your combination valve, or your new pump may fail the same way.

-Arthur

Sebastian wrote: > Hi, my VW passat 2001 engine ATW / 123000miles / Auto-Tranny has the > following problem: >

Hi Arthur,

I ordered a new pump (230$) not too bad I think. wil lbe delivered hopefully next week. so I have time to install over the weekend and to do some testing. THe vacuum hoses are all replaced, so I hope the valve is working. I also had the idea to replace the valve against an electric powered version (combined with the pump (pump on >> valve open / pumo off >>

valve closed), what do you think?

Thanks for the tip about the fuse, I will have a look at that one tomorrow. TTYL Sebastian

PS: will keep you updated.

Hi Arthur,

THANK YOU so much for the fuse location there is a 40Amp. fuse in the (ECU black box) and 2 realys! so stup... anyway, I will get a fuse somewhere and hope the new pump comes in this week.

THANK YOU again !!!

Sebastian

Ever wonder where all that water comes from?

I DO!!!! lol

Hi Arthur, it is me again :-( i replaced the air pump checked the ECR valve (looks good) fuse is installed and the pump is running (at the startup) but the error code P0411 sill pops up (again.. and again..) any suggestions?

O2 sensor (prior to the catalytic converter), the one behind the catalytic converter was just replaced a few month ago.

any other ideas?

THANK's Sebastian

Arthur Russell wrote:

What's a by-product of combustion especially when the engine is cold?

That gets into the secondary air pump? U G L Y

Sebastian,

Sorry, I've been offline for awhile here. If you want to, contact me directly and we can brain-storm a little (assuming you haven't already figured it out) I'm sure you'll be able to return the favor in vag-com info at some point.

-Arthur

Sebastian wrote: