scrnchr

2004 Tahoe LS 4WD

Failed emissions. Codes indicate gas cap and evap leaks. Replaced gas cap with OEM. Purchased:

ACDelco 214-2149 Professional Vapor Canister Purge Solenoid




I put the truck up on ramps and looked all over near the rear axle and differential, where I've read this is supposed to be located. Also looked as best I could around the front of the gas tank. Cannot spot it.

Where is this located? I think I'm losing my mind.

Thanks.

EinST

It's under the hood. There's usually a vapor line coming up the firewall into the purge valve and then another one going from the purge valve to near the TB. I think you meant to get the vent solenoid which is connected to the EVAP canister under the vehicle on top or near the fuel tank.

scrnchr

This is the part I bought, which all the parts websites said is the correct part for my 2004 Tahoe LS.



But this two-piece kit is also available, althought the websites say this is NOT the right kit for my Tahoe.




Here is what I see when I crawl under my truck.

This is near the back of the gas tank. This rectangular piece looks a lot like the one in the two-piece kit above.



This is the Evap Canister mounted on the side of the gas tank.


One of the lines from the Evap Canister leads to the unit pointed to by the arrows in the next three photos. I can't tell if this is the other part shown in the two-piece kit above. Does anyone know what this part is?







Finally, this is a little more forward. I'm not sure what the arrow is pointing at, but I don't think it's part of the evap system. Maybe part of the 4WD shifting system? I have no idea.




Here are a couple of GM diagrams I found, and a couple of pages from the GM manual. I see there is some confusion between "purge valve" and "vent valve". The manual says the purge valve is under the hood, on the intake manifold. But I have looked at that, and the part I bought is much bigger. I think other GM trucks, especially pickups, have the part I bought near the gas tank. And I think what I bought is a "vent valve" regardless of the word "purge" in the name of the part.










Any ideas on what I have here?

THANKS.

EinST

I think the vent solenoid is the rectangular component "near the back of the gas tank" with the air vent holes on top. The electrical harness there should have white and orange wires. Your 214-2149 is apparently a redesigned part. Then, the 214-2082 kit adds a filter box located away from the solenoid. You'll see what I mean if you search for TSB "02-06-04-037F" and then take a look at a PDF copy.

scrnchr

Thanks for the reply, EinST. I took a look at TSB "02-06-04-037F". Is there something similar for Tahoes? Also, that TSB was for DTC P0446 (Restricted/Blocked EVAP Vent Path). (Although I realize you were directing me to the photos and descriptions in it.)

The codes I got are:

P0101 (Mass Air Flow (MAF) Circuit Range/Performance Problem)
P0449 (Evaporative Emission (EVAP) Vent Solenoid Control Circuit)
P0455 (Evaporative Emission Control System Leak Detected (Gross Leak))
P0455 Pending

edit: I forgot to mention that I replaced the Tahoe gas cap with an OEM cap.

I removed the MAF sensor and cleaned the wires with carb cleaner. I'll see if the code resets.

I reset the codes Sunday afternoon after reading them. The CEL was back on a few hours later, the second or third time the truck was started (not driven more than a few hundred feet). I'll read the codes and see which checks are ready in the next day or two.

scrnchr

OK, with your recent thoughts I think I may be figuring this out.


Here is a close-up of what I have:




I found this statement on another GM forum:

"I just changed mine for Tahoe 2003, and as per our dealer the box shaped one is not available anymore, I replaced it with the rounded one (GM 25932571 AC 214-2149), instead of the box shaped GM 10382105 AC 214-1078)."

This is the only photo I could find of the poster's "box shaped GM 10382105 AC 214-1078)":



It appears to be the part I have.


And the poster's "rounded one (GM 25932571 AC 214-2149)" is what I have purchased:




So, it would appear I just need to replace the rectangular solenoid I have with the new round one.

Does that sound correct?

Any idea how to get the old rectangular one down? And how to mount the new one up there? From the Sierra posts, it sounds like the new one is being cable tied in many of these installations.

Thanks.

scrnchr

Now I found that the box shaped solenoid is still available: AC Delco 214-1091 Canister Purge Valve

I think I'll go with the round one I have, though, if it will fit up there.

I think GM could do a lot better job of putting out information on this. If every owner just ran to the dealer for every problem, we'd probably not be keeping GM vehicles.

EinST

You should be able to wiggle/slide the vent solenoid out after taking off the electrical connector and vent hose. As for P0449, it means an electrical problem in the EVAP vent solenoid circuit, i.e., an open or short in the wiring or in the solenoid winding. The monitored voltage level on the circuit should read low when the solenoid is energized and vice versa. I've posted on this site more than once why this is so.

scrnchr

I was able to replace the box shaped solenoid with the new cylindrical solenoid today. I reset the codes and will see what happens in the next few days.

scrnchr

I'm still waiting for the EVAP check to go off "NOT READY" on the reader. All other checks have completed. I'm still getting the P0101 MAF DTC. I'll start a new thread about that.