Is this really the EVAP Valve?

TexasCoder · Post by **TexasCoder** » 21 May 2011, 08:19

So, I get up this morning, itching to get out to the garage to tinker on the 2004 2.5T XC90 (oil change, rotate tires, brake inspection), and I find this waiting for me:

: EVAP Valve?; CIMG5323.JPG (236.99 KiB) Viewed 3872 times

One line leads to the intake manifold, one leads to what appears to be the leak detection pump and the other hose runs under the fuse box, in what appears to run back to the fuel tank. The upper portion of the valve has a broken tab, which explains why it broke off and is held in by the wire harness and spring. I hooked up my scanner, and oddly enough there are no codes, so either this is not part of the EVAP system, or it is, and the valve has remained open and not caused a code

Before I start calling dealerships and searching the net, I thought I would ask you folks what this is, and if my guess is correct. VADIS is no help, it shows what appears to be a similar part, but not 100%.

Post by **jimmy57** » 21 May 2011, 09:17

that is the brake booster auxiliary vacuum pump switch. The aluminum housing unit the hard line leads to is the electric vac pump.
Leakage detection pump is back by rear axle.

TexasCoder · Post by **TexasCoder** » 21 May 2011, 09:22

jimmy57 wrote:that is the brake booster auxiliary vacuum pump switch. The aluminum housing unit the hard line leads to is the electric vac pump.
Leakage detection pump is back by rear axle.

Sweet, thank you man! I am glad I held off on ordering the "Valve" list on the web. It just did not look the same. Thanks again man, I am going to get this replaced.

So being the auxiliary switch, is that why there are no codes stored in the ecm?

Post by **jimmy57** » 21 May 2011, 09:49

the electric vac pump is not tied to the ECM. It's purpose is to provide vacuum when the variable cam timing has set cams for cold warm-up emission improvement. The phasing of cams at that time results in almost no vacuum production and thus no supply for vaccum power brake booster. The switch triggers pump when vaccum falls below 8 inches +/-.
If you pay attention in cold weather starts (below 50 degrees f) you can tell the engine is laboring when it first starts and goes to the high idle, this is the cam phasing for emissions reasons.
Anyway, the ECM does not have any diagnostics for the switch or pump.

Some switches are serviced with the hard hose.

TexasCoder · Post by **TexasCoder** » 21 May 2011, 09:56

jimmy57 wrote:the electric vac pump is not tied to the ECM. It's purpose is to provide vacuum when the variable cam timing has set cams for cold warm-up emission improvement. The phasing of cams at that time results in almost no vacuum production and thus no supply for vaccum power brake booster. The switch triggers pump when vaccum falls below 8 inches +/-.
If you pay attention in cold weather starts (below 50 degrees f) you can tell the engine is laboring when it first starts and goes to the high idle, this is the cam phasing for emissions reasons.
Anyway, the ECM does not have any diagnostics for the switch or pump.

Some switches are serviced with the hard hose.

Outstanding man! Thank you for the description. This type of information is priceless, by the sound of it, how long have you been wrench'n on volvos?

Post by **jimmy57** » 21 May 2011, 11:21

Involved with Volvos for just short of thirty years.

trstjohn · Post by **trstjohn** » 22 May 2011, 06:07

Here's the part number:
http://www.volvopartswebstore.com/produ ... 45383.html

I havent checked to see who else has this part yet. When you get it let me know who you get it from and how much.

trstjohn · Post by **trstjohn** » 22 May 2011, 06:08

In the mean time, before you fix it, I used a twistie tie to tie down the switch.

TexasCoder · Post by **TexasCoder** » 27 May 2011, 13:52

Thanks everyone for the information! You guys have really saved me alot of searching! I ordered the part from a local dealer (http://www.volvowholesaleparts.com)

The total price after shipping and tax was $66.08. The part number is: 31265826 and is listed under VADIS as "Cowl - Components on dash panel - Module Module 2003 – 2011" for my VIN. Strange place to post it, but the sales guy assured me it was the right part, and when I opened the package...BAM...it was dead on!

Here is a photo of the new piece, all shiny and nice...to bad it wont stay this way

Thanks again guys!!!

: Volvo Part; CIMG5325.JPG (572.14 KiB) Viewed 3811 times

TexasCoder · Post by **TexasCoder** » 27 May 2011, 13:53

trstjohn wrote:In the mean time, before you fix it, I used a twistie tie to tie down the switch.

Great minds think alike! I put one on the day I found it, and that thing has head together! Thanks for the tip!