2007-2010 P0449 EVAP Canister Vent Solenoid FIXED +TSB

There's so much information out there on replacing the EVAP Canister Vent Solemnized (CVS) in our AV's and I just wanted to update it for those 2007-2010 owners out there that might currently be experiencing the dreaded P0449, or P0445 (with tighten gas cap on the DIC) codes.  This also applies to those who are experiencing difficulty filling refueling.

If you're getting these code's the first thing you're going to want to do is look up the most recent TSB on the issue...

TSB #09-06-04-028C

You will need the following two parts, I've also included the prices I paid at the dealership in MD on 8/18/2011.  These are GM direct parts and are only available through the parts department at a dealer.  The older version/fix for the EVAP CVS, which some 2007 owners have referenced/posted in regards to, are no longer manufactured by ACDelco.

EVAP CVS #20995472 ($71.xx)
Jumper Harness #19257603 (31.xx)

the EVAP CVS part you will be replacing is the entire unit, a hose that runs up to and attaches near the filler housing, and a hose that runs into the EVAP canister which is mounted near the rear of the gas tank, in front of the differential.  The new jumper harness really seems to be another way for GM to nickle and dime us...my old one would have reached just fine, but they changed the connector forcing us to waste another $31.

you MUST drop the spare tire....I don't care how thin/double jointed you are, there's no way in hell you're going to reach it with the tire in place, plus you're going to have to remove the old hoses and reroute the new ones...also, if you're of above average build (i.e. can't crawl under the differential with the truck on the ground) then you're going to have to jack it up.

Otherwise it really wasn't too bad to do...the only tools you really need are a socket set and maybe a pair of needle nose pliers (getting the old hose to disconnect from the evap canister was a B...I actually had to remove a couple bolts that mounted the evap canister to the body in order to lower it a little...my dual exhaust was the biggest obstacle, but there is a heat shield that also was a PITA to get around, and it was only two bolts to lower it)...the TSB does reference drilling a hole in the filler housing, and installing a pin (#10121502) to hold the new CVS valve in place but the parts guy at the dealer just gave me an extra zip tie and told me not to waste my time.

Afterwards I pulled the battery cable to reset the code, and so far after 8-9 start cycles and 100+ miles the light hasn't come back...fingers crossed.

Hope this helps!!!!

Good info thanks for posting 

Thank you for this.  It is extremely helpfull, and in my case, very timely.

I am in the throes of this problem right now.  I have ordered the same two parts that you have called out based on much confusing research and this minor post.  It had mentioned the current part number and the need for the harness.

Fortunately, there is apparently no consequence of running around with this faulty valve.  Although it will obscure any further codes that may subsequently come in.  That, and you won't be able to pass the emissions inspection, of course.

I'm always looking for a silver lining so....Think of this as a good opportunity to practice taking down the spare tire on the familiar surroundings of your dry driveway with no cars/trucks zooming past at speed.  Plenty of time to figure out how to get by the secondary latch system on the spare tire mount.  Check the pressure on your spare, too.  Mine was near zero with sand and grit in the bead.  It needed bead sealer before it would even think about holding pressure.

indeed, my spare was almost flat as well (>8psi)...and it was the first time I've had the wonderful pleasure of jacking the vehicle up with the stock jack .....certainly provided motivation to get a new hydraulic jack for my garage as the one I use for my old CJ7 isn't quite up to lifting the AV...

punk8slvr said:

EVAP CVS #20995472 ($71.xx)
Jumper Harness #19257603 (31.xx)

The new jumper harness really seems to be another way for GM to nickle and dime us...my old one would have reached just fine, but they changed the connector forcing us to waste another $31. Very true!


Otherwise it really wasn't too bad to do...the only tools you really need are a socket set and maybe a pair of needle nose pliers (getting the old hose to disconnect from the evap canister was a B...I actually had to remove a couple bolts that mounted the evap canister to the body in order to lower it a little...my dual exhaust was the biggest obstacle, but there is a heat shield that also was a PITA to get around, and it was only two bolts to lower it)

Click to expand...

Thanks for this write up, I replaced mine tonight and this was spot on for what needed to be done.

I had a he!! of a time getting the white quick connector off the evap canister too. I looked at the new one to get an idea of how it works since you can't see it well on the truck. I ended up pushing the little tabs that are the top down which pushed the rest of the retaining ring down out of the connector and grabbed it with a needle nose pliers and just pulled it out (breaking it) so it would release the old hose. If someone is getting ready to do this, look at the new part and play with it and this will all make sense. I didn't have to drop anything or take any bolts out. If the kit didn't come with new hoses I guess I would have tried to be nicer but it was going in the garbage when I was done anyway!

Great Post!  Wish I had found this sooner.  Just installed mine tonight.  I almost said heck with it because the canister looked much larger than the old one and the vent pipe had a filter on the end unlike the round plug on the original.  Anyway, I went ahead and installed it with little effort.  I did end up breaking the old clip just like everyone else. Carbon's right, just going to throw it away anyway! 

Just did this last week. It wasn't too difficult. Maybe I am dumb, but it took me a while to figure out that the new one didn't slide onto the bracket like the old one did. You have to take the bolt that holds the bracket onto the frame out, then the new one has a bolt hole in it to mount it directly to the frame. Once I figured that out, the rest was cake. Oh, I didn't drill a hole and use the push pin to mount the vent up by the filler opening. I didn't have a push pin, and I wasn't going to buy one or drill a hole in the back of the filler unit. I just used some epoxy to stick it to the backside of the filler unit. Took the negative cable off of the battery for 5 minutes, put it back on, no code since! (Fingers crossed!)

Thanks for this post. It really helped out a lot. Way better than the TSB i had printed out.

I wanted to say thank you also... Good to know its an easy fix and that these DIY fixes ALWAYS beat out going to take it in to the shop. 

I'll be starting on this myself hopefully this weekend.

I just had the dealer do this on my 2008 at 54,000 miles. I had the "TIGHTEN GAS CAP" message and service engine soon light. I thought about tackling it myself but I didn't feel like dealing with it. Total was $242 including 1.2 hours of labor. They found code P0442. The parts list is below:

1 20995472 VENT $73.32
4 12337820 STRAP $2.00 (expensive zip ties)
4 11609970 CLAMP $2.25
9 9438383 HOSE $1.53
1 19257603 HARNESS $30.72
2 10121502 RETAINER $0.49

Comment on invoice states: "TECH FOUND P0442. FOUND FAULT WITH EVAP VENT VALVE AND INSTRUCTED BY GM TO PERFORM A REDIRECT FOR THE VENT."

as soon as I got the parts the problem with refueling when away 

Good information here, thanks.
I just ordered these parts from GMpartsdirect.com for my '08:
20995472 'vent' $37.76
19227603 'harness' $15.82
12597567 'valve' $22.69
Not bad on price but they stabbed me on shipping; $24.42
Maybe I'll have the parts by the weekend; doesn't sound like too big of a deal to change.
See if the annoying CEL goes away.
Are the hoses included? If not what length do I need to buy, and I assume hoses clamps?

WW

MLM said:

I just had the dealer do this on my 2008 at 54,000 miles. I had the "TIGHTEN GAS CAP" message and service engine soon light. I thought about tackling it myself but I didn't feel like dealing with it. Total was $242 including 1.2 hours of labor. They found code P0442. The parts list is below:

1 20995472 VENT $73.32
4 12337820 STRAP $2.00 (expensive zip ties)
4 11609970 CLAMP $2.25
9 9438383 HOSE $1.53
1 19257603 HARNESS $30.72
2 10121502 RETAINER $0.49

Comment on invoice states: "TECH FOUND P0442. FOUND FAULT WITH EVAP VENT VALVE AND INSTRUCTED BY GM TO PERFORM A REDIRECT FOR THE VENT."

Click to expand...

I just had this I expect. For assorted issues around the wife driving to her families cottage next month I went ahead and had the local shop fix it. Bought the truck in early May. The shop ended up adding on a new canister for about $75 (I'll look and edit for specifics when I get home)

So my question to you MLM is; About where do you live? I am in SE Michigan and our labor rates are quite high, but it still seems like I might have gotten the shaft on this one.

I finally got around to fixing this problem today on my 2010.  I bought a kit from Advance Auto Parts (check the link below) for under $70 with tax that had everything I needed to fix replace the solenoid (solenoid, harness adapter, connect hoses, and even cable ties).  If you need to fix this part try getting the aftermarket one if you want to save some cash.  I'll let you know if I have any problems.

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_vapor-canister-vent-solenoid-bwd_10101018-p?navigationPath=L1*14932|L2*14982

I just replaced the solenoid and jumper wire. Cleared the codes as well. While driving engine light is back on with P0049 code again. Any suggestions?

I just experienced this problem on my 09 AVY.  Thanks again to PUNK8SLVR for posting the repair for this problem.

  It took me about an hour to do.  Once I got the spare tire down and out of the way, I disconnected the hose at the fuel tank, then unscrewed the bolt(1/2" socket) holding the vent solenoid canister in position.  Then I cut the 4 zip ties holding the other vent hose in position(this one goes to the back side of the fuel filler door), and removed it from its location.  Once that was done, I worked the fuel vent hose(this one is stiff) away from the fuel tank and removed the assembly from the truck.  I installed the replacement assembly(AC Delco part #20995472)and the wiring harness adapter(AC Delco part#19257603) in the reverse order of removing the old part.  (Purchased them online at Amazon.com).  Getting the fuel vent hose back on the tube at the fuel tank was difficult;  I had to re-position the hose to get it to line up, which let me push the "clip" over the connector on the tube.  The rest was easy.  I then cleared the codes from the computer using my Diablo predator.  So far, no check engine light or "tighten  fuel cap" messages.

Thanks again to all for their posts and helpful tips.  You guys are great! 

Write "at" y'all later.

I got the P0455 code and tighten gas cap warning. Bought a new gas cap but cel came back on. I also noticed a strong gasoline smell that has lingered since my last fill up. Anyone know if that sounds like a symptom of a defective evap canister?

old skool said:

I got the P0455 code and tighten gas cap warning. Bought a new gas cap but cel came back on. I also noticed a strong gasoline smell that has lingered since my last fill up. Anyone know if that sounds like a symptom of a defective evap canister?

Click to expand...

Replaced the evap canister yesterday and reset the cel. Guess time will tell if this solves the problem.

CEL back on. 

This help.

DTC P0455 is a Type B DTC.
Diagnostic Aids
    ? A fuel fill cap that is left OFF after a fuel fill will cause this DTC to set.
    ? A loose, missing, or damaged fuel fill cap can cause this DTC to set.
    ? A blockage or restriction in the EVAP purge solenoid, purge pipe EVAP canister, or vapor pipe, can cause this DTC to set.
    ? A temporary blockage in the EVAP purge solenoid, purge pipe, or EVAP canister could cause an intermittent condition. Inspect and repair any restriction in the EVAP system.
    ? To help locate intermittent leaks, use the J 41413-200 to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the J 41413-SPT .
    ? To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT .
    ? Observe the Freeze Frame/Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition occurs that caused the DTC to set . This may assist in diagnosing the condition. .

Just an update...reset code a second time and this time, reading 0 codes. Maybe just had to go thru some cycles to get rid of the bad code.

Intersting wonder if this is my issue?

I never posted back to this thread...this wasn't my problem. This was...http://chevyavalanchefanclub.com/cafcna/index.php/topic,143523.msg2073349.html#msg2073349

I know this thread started a long time ago and was recently replied last year, so thought I would add this to it. You can buy an evap canister with the solenoid from Advance Auto and other places for about $24 or less. The part is "ACDelco Evaporative Canister Solenoid"; part number 214-2149, comes with a 1 year warranty. The solenoid detaches from the canister (it isn't the same canister as 2007 and up), remove the new and faulty solenoids from the canisters, clean your old canister, insert the new solenoid into your canister, remove the hose that runs from the solenoid to the canister by the gas tank, replace it with about 2' of 5/8" heater hose and two 5/8" clamps.

No need to buy a new canister, replacement lines, coupling connector, etc... Only tool you need is a #2 standard tip screwdriver. You can do the swap in about 30 minutes.

Too bad this site doesn't support images, I could put up a few of the new and faulty parts, receipt, and part description.