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Discussion Starter · #1 ·
HI guys - I had a CEL the other day and the code came back with "solenoid valve for charge pressure control - N75 open circuit". I checked the electrical connection on the N75 and it was fine but my friend noticed a vacuum line from the front of the engine head that wraps under the coolant line and passes by the N75 was cracked and broken off at it's nipple. I got the codes cleared and tied a new piece of vacuum line on and so far no CELs. I had thought that the line tied into the N75 but digging around, it went past it and into a larger fitting further down below...

Any ideas what this line is for? I wish I had a cmera to take a pic of it...

Ben
 

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See my post here: http://www.clubb5.com/forums/viewtopic.php?t=96134&highlight=&sid=b933d6fca0705f977140b24260bfa662

Sounds like you have the same issue.

Oops, reread your post. Is it the one that connects to the manifold on the front right hand side? Very common for that hose to go. I replaced my bosses for him when his CEL came on. It has not returned since.

The link to the other post was for the L hose. It gave me the charge pressure control valve error, that's why I jumped the gun without reading your post more carefully.

Glad you got it fixed yourself!
 

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Discussion Starter · #3 ·
yeah -sorry. It's the small braided line that is at the front of the manifold. I can see how it would be common for it to crack due to the heat of the engine.

but what does this line do? I'm just curious....

Ben
 

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Well, if I am reading the diagram correctly in the Bentley Manual, the hose goes from the front on the intake manifold to the Recirculating valve for turbocharger -N249.

I just ran out to the parking lot to make sure that was it. :wink:

Now the real question is - what does a Recirculating valve for turbocharger do???
 

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Nope, not the diverter valve. This is a valve that is on the right side on the intake manifold at about its midpoint. It's under a lot of stuff so it isn't easy to see.
 

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Ok, I have some pics - not very good mind you because my camera is at home so I had to go with what I had.

Here is the location of the vac hose (red arrow) that you were talking about.


The yellow circle is the location of the Recirculating valve. It is located under the manifold in that area.

Here is another pic of the hose and where it attaches to the front of the manifold.

I have replaced the stock hose with hosetechniques silicone vac hose in this picture.

This last picture is really not that good. On the upper left side you can see where the throttle body attaches to the manifold. I have removed it for cleaning. The needle nose pliers are pointing to the location where the vac line attaches to the recirculation valve.

The old vac line is visible under the pliers.

Hope this helps a bit.
 

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I have not looked at my car. But, Recirculation usually means the EGR system - part of the emissions system. Anyone?
 

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Discussion Starter · #9 ·
the first and second pics are bang-on. that's the line I'm talking about. But it is routed to the left side under the coolant line on my car towards the N75, then drops down to a fitting down near the engine cover - not near the recirc valve circled in yellow in the first pic. hmmm.....german engineering? :D
 

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What model year is your car, bwhiting? The pictures I posted are from my 2K GLS. I even went out to verify where that vac line was going. If you have a newer model, it must be a running change.
Hmmmmmmm... :suspicio:
 

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Ok, here is a picture showing roughly how the vac lines on my car are run.



The Red Line is the one in question. I tried to indicate the direction the lines plug into their termination points.

The light blue line is the very short one, only about 5 inches or so.

The pink/purple one goes to the combi valve (so I am told) close to the firewall on the left side of the engine bay.

The dark blue one goes to the diverter valve right under the belly pan on the left side of the engine bay.
 

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Strange! I got together with Tregate from ClubB5 a little over a month ago, (he has a 2K GLS too) and we replaced the 4 vac lines indicated above and cleaned our throttle bodies at the same time. His vac lines were run just like mine. My bosses B5 (2001 GLS) also had the same vac line runs. I replaced the light blue one and the red one (the one that failed) on his car.

I don't know why yours are different. :???:

Check this post too, has the same line runs that I have.
http://www.clubb5.com/forums/viewtopic.php?p=299186
 

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vwhiting,
what year is your car? I have a '99 1.8T (same engine as '98 and '99) and my vacuum hose (with the red arrow in first pic.) runs to the diverter valve. If you're running a AEB engine, that is probably correct. If you have a 2000 or newer, you may want to look into this more.

Quick question for all;
If these vacuum lines are running of the intake manifold, and they all start with the same size nipple, shouldn't they have the same amount of vacuum? In other words, maybe it doesn't matter where you have the two connected to cause they both provide the same vacuum at the same time.
 
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