What did you do to your NBS GMT800 Tahoe/Yukon Today?

[Sam Harris]

Sam the bottom line is you either have to bite the bullet for a smoke test (which may not tell you anything) or start replacing parts, you can try the easy one first it's about $25-30 for the solenoid on the intake under the hood, if that doesn't do it then you gotta move on to the canister and vent solenoid. all 3 parts oem runs you about $200.00 a smoke test is usually about $100 then your still going to need to replace parts (if the source is found) or end up replacing them anyway. It's kind of a dammed if you do and dammed if you don't. it's not hard to do, easier than it looks. The kicker is it takes about 3 days for that code to clear for sure once the problem is found. The system has to pass evap 3 times starting cold and then getting hot (rinse and repeat) if you have the tech2 you can do the evap test but it's a pain in the ass, ac power has to be connected, you have to prep the tech2 for the test, start the truck cold, hold the rpms between 2k~3k for a period of time, yada yada

Thanks for the feedback. I wasn’t even aware there were 2 solenoids. I thought it was just the one at / near the canister.

 

[iamdub]

Thanks for the feedback. I wasn’t even aware there were 2 solenoids. I thought it was just the one at / near the canister.

Yup. The one on the side of the intake manifold is the purge solenoid and the one near the charcoal canister is the vent solenoid.

 

[Sam Harris]

Your trailer light circuits should work fine; those are usually already fused. But if you ever need to add a brake controller and/or a 12v feed to the trailer, there are wires near the underhood fusebox that will need to be connected, and large fuses installed. Doesn't sound like you'll need those at this point, though.

Thanks Steve. Yeah, I’ve looked at some brake controllers and figure if I end up towing anything heavier, (with brakes), I’ll add a Tekonsha most likely.

 

[Doubeleive]

Thanks for the feedback. I wasn’t even aware there were 2 solenoids. I thought it was just the one at / near the canister.

if you end up doing the rear one it has a long tube and a filter at the end that attaches inside the body up near the top of the fill spout, if you disconnect the fill spout and pull it down it makes the job very easy instead of trying to reach up and get a zip tie on in a tiny space. they put the filter up there to help keep dirt and dust from getting into it.

 

[treehan77]

You could bench test the solenoid by the can. I got a replacement (AC delco) and it didnt even work! Just need 12v power and ground to see if it clicks really.

 

[clandr1]

So I’ve had a recurring P0455 for months. It comes and goes.. y’all are probably saying: this sounds familiar.. why are you repeating yourself..?

So replaced the gas cap a couple weeks ago. I didn’t clear it, intentionally, expecting it to clear on it’s own. It didn’t.. After about a week, I got sick of it, and cleared the code.

All good until today, when I filled my tank. So, no joke, as soon as I cranked the engine, there’s my familiar CEL.

Since I’ve replaced the gas cap, and since the CEL illuminated immediately after filling the tank, I’m thinking it’s the solenoid.

Anyone have any thoughts / opinions on how likely it is the solenoid..? Something else..? I know the possibilities, just hoping for an easy fix. I doubt I’ll have to replace the canister and all, since I never have trouble filling the tank, but realize there are a few possibilities here.

I took my rear purge canister off, shook the dust out (there was a LOT), blew it clear with compressed air, then sprayed some silicon lubricant in the area where the solenoid opens and closes. It seems to work great now. That might be worth a shot before replacing it.

 

[clandr1]

I attended a night vision shoot last night and snapped a picture of my truck:

 

[Sam Harris]

I attended a night vision shoot last night and snapped a picture of my truck:

View attachment 276027

That’s awesome!

 

[Fless]

Thanks Steve. Yeah, I’ve looked at some brake controllers and figure if I end up towing anything heavier, (with brakes), I’ll add a Tekonsha most likely.

Love my Tekonsha P3. The only time I use it is when I tow a rental camper.

 

[mikeyss]

Hubby and I got tired of the 06 Sierra Denali's horrible brake performance compared to our 09 Tahoe... So we upgraded the front brakes to the GMT900 style, and now it stops so much better.





I didn't get many pictures because this upgrade has been done by so many of you guys, but I had to have the proof