Fresh Air Valve - 986 Forum - The Community for Porsche Boxster & Cayman Owners

bmx672 · 08-14-2011, 05:43 PM

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Does anyone know where it is? Its on the same circuit as the ORVR. Controlled by reed contact and the E6 fuse.

Dale_K · 08-15-2011, 04:09 AM

I haven't heard that terminology "fresh air valve". There are two valves behind the right headlight in a black plastic housing. You can also get to them by removing the fender liner. One of them connects to the atmosphere through an opening by the fuel door hinge but I don't know if that is the valve you're talking about.

insite · 08-15-2011, 07:08 AM

if it's for the HVAC system, the fresh air valve is located beneath the cabin air filter. pop the hood. the cabin air filter will be all the way back & left. remove it; just underneath is the valve that decides whether to recirculate cabin air OR to suck in fresh air from outside the car.

bmx672 · 08-15-2011, 10:07 AM

Thanks Insite!
If I'm correct then that valve uses the same power wire that the reed switch does. Where those two meet is where my problem is I believe. Now thats going to be the trick... finding where they actually meet!

insite · 08-15-2011, 10:29 AM

they should merge behind the climatronic unit in the dash. remove the climatronic. it should have four connectors. the red wire on the beige connector feeds +5V to the mixing flaps, the footwell defrost valve, and the outside air valve.

what is the issue & what are you trying to do? what are you calling the 'reed switch'?

bmx672 · 08-15-2011, 10:52 AM

The issue: I am unable to fill the tank past half.

The reed switch (magnetic switch attached to filler tube) was not activating the vent valve for the gas tank. The gas pump nozzle flips the little cover open and the cover engages the reed switch (magnetically). Thus sending everything in motion for the tank to vent while filling.
(I checked all the obvious issues, fuses, the tank, sending unit, obstructed spit back valve in the neck etc etc.)
My next steps were to check continuity and power to all the switches and valves. Everything looked good and worked when power was applied separately. But when everything was connected... nothing!
Next step... to look at the wire diagram in the Bentley. On that same system of wires is the "Fresh Air Valve" my guess is that when fueling up the car shuts off outside venting to avoid pulling fumes into the cabin. There has to be a short there at that connection because when we cut that wire and used a different configuration the filler flap activated the reed switch and the vent valve opened for the fuel tank! Everything worked when we eliminated the "Fresh Air Valve" from the daisy chain. So therein lies the problem I believe.
My next step is to see if the "Fresh Air Valve" works... if not maybe theres just corrosion where the wires split? Not sure...

insite · 08-15-2011, 11:09 AM

what year is your car?

bmx672 · 08-15-2011, 11:57 AM

It's a 2000...

insite · 08-15-2011, 12:27 PM

ok, this is not intuitive at all. the voltage supply block is actually in the trunk. it supplies:

1. mass air sensor
2. varioRAM actuator
3. secondary air injection valve
4. tank venting valve
5. DME relay KL.87
6. camshaft adjustment actuators

the junction block is located in grid position 15cN, which is highlighted in red below. the point is called terminal 30.

bmx672 · 08-15-2011, 01:55 PM

THANKS Insite! I cant wait to get back into the car tonight and see what I can find! I'll let you know!

Thanks again!

bmx672 · 08-15-2011, 02:43 PM

Insite, would you know where terminal VS.24 is located? That's the tie in for the reed switch, tank vent valve and the fresh air valve in the Bentley wire diagram. We think that's the location where the problem might be. But i have no idea where VS.24 is. You had mentioned that it could be on the climatronic. Would they tie in at the location in the trunk on the diagram you supplied? Not sure if you know but any help would be greatly appreciated.
Thanks!

Dale_K · 08-16-2011, 09:13 AM

I don't know the terminology of "fresh air valve". But it might be one of the pair of valves behind the right headlight. I know you're already working in that area and don't want to lead you astray. One of them definitely leads to the atmosphere and I thought it was the one that let fresh air into the tank during driving. If one of those valves is drawing down the circuit at a time when they're supposed to work together you might get a situation where the other valve works OK when the bad valve is disconnected.

Truth is I don't know. Hope the magnetic switch helps you.

bmx672 · 08-16-2011, 09:59 AM

Dale, just got the switch 15min ago!!! Thanks a TON! There is part of me that thinks there could also be a problem with the switch... if I do bypass the Fresh Air Valve (the valve that opens and closes the cabin filter to the atmosphere) I might need it. It seems the one I have sticks. I'll know more tonight.

I just wish I knew where VS-(wire connection) #24 was for certain before I go deeper into the car. My Bentley shows it in the wire diagram... I believe that’s where the short may be happening and drawing power from the system preventing the switch to open the vent valve. That's the connection point of all three vents/switches mentioned below...

The other vent in that unit up in the front part of the wheel well is part of another system... It's not tied into the tank vent system. The tank vent components are the Vent valve, the fresh air valve and the reed (magnetic) switch. Those are all on the same circuit.