Code P0443

MileHiSierra · November 30, 2017

Good morning All,

I have an 05 Sierra 2500HD, 6.0, 4x4, Automatic, with 170k miles.

Back in march I had to replace the engine with an ATK reman. The bottom end was going out.

I also replaced a great many peripheral parts at the same time.

*Intake Manifold, Evap purge valve solenoid, Purge valve hose. vent valve and solenoid, evap tank, gas cap (all genuine gm parts)

I cannot rid myself of code p0443, I feel like I have read 1000 posts on the subject, and nearly all, have not reached any resolution.

I need to sell my truck, but with this code ever present, it makes it difficult.

the truck starts fine, idles at 600 rpms, but has a decided shudder from 1500 to 2500 rpms. Seems to have lots of power, no extraneous gas smells. no hesitation. Just that stupid code.

I just ordered and installed another purge valve solenoid, cleared the code, started it up again, and without hesitation, the cel came on again.

My frustration lies in the fact that most all the system is brand new (gm Parts)

can anyone help.....Pleeeeaaase......

I personally don't believe the evap systems are a conspiracy to destroy the free world. (sorry)

davester · November 30, 2017

Have you checked that the purge valve works? That the wire harness is supplying power and ground?

Maybe sign up for alldata.com or helminc.com to gain access to the full-service manual for your truck, and go through the diagnostic procedure that GM has for this code.

MileHiSierra · December 1, 2017

I will look into alldata and helmic.com. I have checked that there is voltage, came in at 13.1 volts, as far as checking to see if it is working...no. I just assumed that new gm parts would work. I have installed two or them so far. I will check that it does first thing in the morning. Thanks for the suggestions.

Any suggestion on how to check the ground? Do I just need to tear the wire harness completely apart? Kind of hoping I could avoid that...

MileHiSierra · December 2, 2017

Davester.... I did pull off the solenoid and ran a check on it and it indeed was working. Voltage coming in was good, so I started investigating the ground. To which I found that the ground wire coming from the plug was brittle and corroded. As I moved it around, it snapped. I happened to have a little Blazer in my driveway (I'm rebuilding) so I borrowed the plug from that and installed it on the truck. Viola'! no cel! However, That is for the moment. Should it change and the problem resurfaces, I will post again. for now, all is well. Sometimes it just takes someone to point out the obvious. Thanks for your help.