Jump to content

Server Lease Renewal/Software Licenses

Our yearly server lease, software licenses, as well as hardware operating costs, WERE due Dec 4th, 2022. Our current donations have fallen far short of the funds we need to renew. Please remember the RennTech.org community is Member supported so please consider a donation to help...  THANK YOU!

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)

1999 Boxster Po446


Recommended Posts

I'm sure this has been answered before, but I'm not getting much info when I do a search on it.

Took my boxster in for its annual inspection and it failed. (The check engine light was burned out too!!!!)

PO446: Evaporative Emiss Control Sys. Vent Control Circuit Malfunction.

Any ideas where to start or what this might be?

Thanks,

Richard

Link to comment
Share on other sites

  • 2 weeks later...

That is the same diagram that I have studied in my maintenance manual. It is a really poor picture that doesn't tell you much (not detailed enough).

Does anyone know which of the three lines attached to the evap canister is the purge line? There is one on top, and two on bottom. Of the bottom ones, there is one towards the rear of the car and one toward the front of the car.....

Is there a check valve on any of the lines?

Thanks!

Richard

Link to comment
Share on other sites

Something else strange.... The purge valve works when I apply 12v. When I read the output voltage going to it, I only get 6.66 (appropriate....)

I'm not sure what triggers it to go to 12.

Any other ideas on what might be causing the error? The carbon canister itself??

Richard

Link to comment
Share on other sites

On the EVAP system there are two solenoids and one pressure sensor. I have found the Solenoid that attaches to the carbon canister, and I have found the differential pressure sensor. Does anyone know the part number or where I can get the solenoid that is under the intake manifold?

I suspect this one is the problem. It is a normally closed valve and when I put power to it, it will open. When I remove the power it will close.... (seems normal right??) When I turn off the power supply instead of removing the alligator clip the valve stays open...... I suspect that when the power bleeds off instead of shutting off immediately the valve sticks.

Any thoughts? Got a part number?

Richard

Link to comment
Share on other sites

That is the same diagram that I have studied in my maintenance manual. It is a really poor picture that doesn't tell you much (not detailed enough).

Does anyone know which of the three lines attached to the evap canister is the purge line? There is one on top, and two on bottom. Of the bottom ones, there is one towards the rear of the car and one toward the front of the car.....

Is there a check valve on any of the lines?

Thanks!

Richard

from the valve hosing in the front. the side line vents to air. The second line goes the the evap canister -- I think the 3rd line goes to the fuel tank which

then there is a line that heads to the back of the car. -- maybe this line is the one that heads back to the engine... I never traced it completely.

I spent a month tracking down a similar problem and replaced everything -- finally replaced the EVAP shut off valve (back by the engine) and now it works perfectly.

Try that one first -- might save you $300 in parts and a ton of shop time.

Mike

Link to comment
Share on other sites

UPDATE - RESOLVED

Mike, thanks for your reply. I had ordered the EVAP shut off valve (which is underneath the left intake manifold) about an hour before your post. Your email helped make me feel better about the decision. Gratefully, that is what actually fixed the problem!

The line from the intake manifold connects to the top of the fuel tank through the differential pressure sensor. There is a line from the gas tank to the bottom of the carbon canister (I think the connector towards the rear of the car). The other connector on the bottom connects to a mechanism on the filler neck. The line that attaches to the top of the carbon canister is the vent line that for some strange reason goes all the way to the back of the car (maybe to keep the fumes to the rear?).

The solenoid on the carbon cannister is a normally open device.

The solenoid under the intake manifold is a normally closed device.

You can use a 9v battery (with alligator clips) to actuate the valves.

For a vacuum (or pressure, but be really careful with pressure!!!)test you would close the valve on the carbon canister to make sure there weren't any leaks in the lines.

In my case all the solenoids worked just fine. I had a variable power supply that I set for 12 volts and used it to actuate the EVAP shut off valve under the manifold. When I connected or disconnected the alligator clip, the solenoid always closed immediately. When I left the alligator clip attached and instead just turned off the power supply, the solenoid didn't always close. (I had a hose connected and was blowing air with my mouth through). I am guessing that as the power bled down instead of immediately being removed the solenoid would stick.

What a really fun experience. (ok, not really). But, while baby was up on jack stands, she got new plugs, new filters and an oil change.

Thanks all!!

Richard

Edited by RichardB
Link to comment
Share on other sites

UPDATE - RESOLVED

Mike, thanks for your reply. I had ordered the EVAP shut off valve (which is underneath the left intake manifold) about an hour before your post. Your email helped make me feel better about the decision. Gratefully, that is what actually fixed the problem!%

As much as this board has helped me -- it's nice to give back!

Mike

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.