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Help Replacing the Electronic Change Over Valve


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This week I'm trying to fix CEL codes P0410 and P1411 so I can get my car in for its Smog Check later in July (2001 Boxster, 47K miles). I have checked the Secondary air injection pump and know that it is working properly, so next I'm replacing the Electric Change Over Valve. Does anyone know if I can do this by just removing the resonance tube, or will I need to do this through the passenger compartment? I'm not found of having to remove the seat, poly rib belt and especially the alternator if I don't need to!

post-9146-1246325000_thumb.jpg

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Well, since I did not receive any response on this, I decided to try it anyway. I removed both cross tubes (throttle body and resonance tube), and can positively confirm that the Electronic Change Over Valve can not be reached this way. You would also need to pull the intake distributor, which looked daunting. :o

Next I removed the seat, fire wall engine cover and removed the Alternator. From here you can see the valve, but it still does not look easy to replace since it is wedged under some tubing and wiring. More tomorrow, with some pictures, as I continue.

On the plus side, it did give me the a chance to throughly clean the throttle body and wipe out as much of the intake distributors as possible. :) Since I changed my AOS last week, I should be good to go once I get it put back together again.

Edited by Terry
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Are you replacing the solenoid valve for the secondary air pump? If so, you can reach this from the top of the engine compartment. I don't see any valves associated with the secondary air in your pic.

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No, the secondary air pump is working great. My car is back together and running again so I thought I would post some more pictures and observations.

I'll post these in three parts due to the picture size limit.

Valve Replacement: First of all, replacing this valve is a bear the first time around since there is very little space to work in - - - 2nd time around will definitely be faster. I have attached a picture showing the valve removed. Notice the swollen rubber connectors and small section of broken vacuum line - - - more on that later.

post-9146-1247275544_thumb.jpg

Looking at the picture of the valve going in, you can see the fixed mounting tab that it slides onto. This takes a lot of effort due to the cramped space. Notice the locking tab at the bottom of the valve. To remove the valve, you must locate the tab and push down (or in my case, and maybe an easier way, it broke off), and you must remember to push your new valve all the way on until it locks in place.

post-9146-1247275561_thumb.jpg

Alternator: Getting this back in is significantly easier if you use a press or C-clamp to drive back the sliding nut/lock back a small amount (see circled area on the photo).

post-9146-1247275667_thumb.jpg

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Part 2.

Vacuum system: The typical diagram (attached) does not really match my car (2001 Boxster). You will find two “Y” connectors instead of one. The lower connects directly to the vacuum tank with one arm of the “Y” going to the second “Y” and the other to the Electronic Change Over Valve. If you have oil on the vacuum lines, then you should replace the rubber protective tubes (what the stiff vacuum tube pushes into.) These expand when in contact with the oil and may no longer hold a vacuum.

post-9146-1247276509_thumb.jpg

post-9146-1247276533_thumb.jpgpost-9146-1247276544_thumb.jpg

Rant: Went to Steven’s Creek Porsche (Santa Clara, CA ) to buy some of the small diameter, stiff, vacuum line since I broke one of the sections. The person running the parts desk said he had never seen vacuum lines like I was describing (the lines are shown in the Porsche Catalog, but without a part number) and wanted to sell me the larger, more flexible line. A second person working parts backed him up saying they had never seen a vacuum line like that before. Next I called Fletcher Porsche in Fremont, who said they had a meter of it in stock. I’m finished with Steven’s Creek. Last week a bought a lower hose clamp from them for my AOS replacement, and they changed ~$8 for the same clamp that Sunset Porsche charges ~$2 for. Rant Over.

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Part 3.

Throttle Body: I not sure why this is so often a struggle for people? Total time for me to take it out, clean it and put it back in probably totaled less than 45-minutes with a cold engine. The workshop manual says to just remove the air intake tube where it attaches to the throttle body and then remove the throttle body with the cross tube as one unit. I believe this is easier than having to remove the entire air intake tube and then trying to unbolt the throttle body with the cross tube in place. See pictures of throttle body out and disassembled for cleaning. Putting the intake tube back on takes a bit of effort. If you have not done it before it does need a little force, but it took me less than a minute for this part. The nice thing about doing it this way, is that you can clean the connecting tubes and reach part way into each of air distributors.

post-9146-1247276857_thumb.jpgpost-9146-1247276875_thumb.jpg

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Part 2.

Vacuum system: The typical diagram (attached) does not really match my car (2001 Boxster). You will find two "Y" connectors instead of one. The lower connects directly to the vacuum tank with one arm of the "Y" going to the second "Y" and the other to the Electronic Change Over Valve. If you have oil on the vacuum lines, then you should replace the rubber protective tubes (what the stiff vacuum tube pushes into.) These expand when in contact with the oil and may no longer hold a vacuum.

post-9146-1247276509_thumb.jpg

post-9146-1247276533_thumb.jpgpost-9146-1247276544_thumb.jpg

Rant: Went to Steven's Creek Porsche (Santa Clara, CA ) to buy some of the small diameter, stiff, vacuum line since I broke one of the sections. The person running the parts desk said he had never seen vacuum lines like I was describing (the lines are shown in the Porsche Catalog, but without a part number) and wanted to sell me the larger, more flexible line. A second person working parts backed him up saying they had never seen a vacuum line like that before. Next I called Fletcher Porsche in Fremont, who said they had a meter of it in stock. I'm finished with Steven's Creek. Last week a bought a lower hose clamp from them for my AOS replacement, and they changed ~$8 for the same clamp that Sunset Porsche charges ~$2 for. Rant Over.

Thanks for all the additional info etc. FYI the vacuum line is called Tekalan - I will tackle this job in a couple of weeks myself. FWIW 99 recently passed CA smog even though I had just reset the P0401/1411 CEL -

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Thanks for all the additional info etc. FYI the vacuum line is called Tekalan - I will tackle this job in a couple of weeks myself. FWIW 99 recently passed CA smog even though I had just reset the P0401/1411 CEL -

It's handy to know that this type of vacuum line in called Teklan. While the Porsche Catalog does not list a Porsche Part number for it, the line I picked up from Fletcher's had part number: 000-043-205-01

While you never know, I doubt I would pass smog with the P0401/1411 CEL on my car since it is not an intermittent problem. Even after I clear it, the light returns again very quickly. Unfortunately, replacing the electronic change over valve did not fully fix my problem as I still have code P0401. I have ordered the air shut-off valve and some additional fittings to complete rebuilding the vacuum system.

post-9146-1247786717_thumb.jpg

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While you never know, I doubt I would pass smog with the P0401/1411 CEL on my car since it is not an intermittent problem. Even after I clear it, the light returns again very quickly. Unfortunately, replacing the electronic change over valve did not fully fix my problem as I still have code P0401. I have ordered the air shut-off valve and some additional fittings to complete rebuilding the vacuum system.

post-9146-1247786717_thumb.jpg

Terry:

Nice write-up and excellent photos with labels!

Thanks for posting.

Regards, Maurice.

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  • 5 years later...

Part 2. Vacuum system: The typical diagram (attached) does not really match my car (2001 Boxster). You will find two “Y” connectors instead of one. The lower connects directly to the vacuum tank with one arm of the “Y” going to the second “Y” and the other to the Electronic Change Over Valve. If you have oil on the vacuum lines, then you should replace the rubber protective tubes (what the stiff vacuum tube pushes into.) These expand when in contact with the oil and may no longer hold a vacuum. attachicon.gifBoxster_...n_System.jpg attachicon.gifUpper_Y.jpgattachicon.gifLower_Y.jpg Rant: Went to Steven’s Creek Porsche (Santa Clara, CA ) to buy some of the small diameter, stiff, vacuum line since I broke one of the sections. The person running the parts desk said he had never seen vacuum lines like I was describing (the lines are shown in the Porsche Catalog, but without a part number) and wanted to sell me the larger, more flexible line. A second person working parts backed him up saying they had never seen a vacuum line like that before. Next I called Fletcher Porsche in Fremont, who said they had a meter of it in stock. I’m finished with Steven’s Creek. Last week a bought a lower hose clamp from them for my AOS replacement, and they changed ~$8 for the same clamp that Sunset Porsche charges ~$2 for. Rant Over.

 

 

this is an old post but I am hoping someone is still watching it. 

I have a 2001 Boxster S with a similar hose setup (i.e. two Y connections instead of one). however on mine the lower Y only to the second Y and the vacuum tank. the third only has a short piece of hose that goes nowhere. the second y connects to the resonance tube boot and to the Change over valve. 

looking this post it seems the change over valve should be connected to the first Y, but what is connected to the second Y?

Thanks

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  • 3 years later...

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