I've had a P0440 code on my 96 Jimmy 4x4 for the past few months. If comes on for a few weeks and then goes off for a few weeks, and then comes back on. I believe this is an EVAP system leak of some sort.

I think my best bet is to just start swapping parts (since i dont have any of the tools mentioned in the p0440 diagnotic chart).

Does anyone know the most likely cause? I'm thinking it might be the purge solenoid.

Any other pointers would also be appreciated.

 

You could test things out:
P0440 - Evaporative Emission Control System

This code is somewhat general.

 

I was hoping that there might be a common problem that causes this code.

I guess I could try diagnosing the problem, however, I dont even know where some of these components are located. Does anyone if there is a manual or something online that at least shows where the EVAP parts are located?

 

The search function also works!

 

I have a 1996 with simalar issue. Accept I am getting P0446. And I also cannot find the evap canister. It reads multiple intermitten misfire on all cylinders, but only runs rough at the initial take off, turn the corner it smooths out. I only have 7000 miles on the remaned engine with all new parts, so Im leaning on a evap issue. I will be getting under it later today, so I'll get back on here tomorrow.

 

same code on mine...i just keep the scan tool in the armrest and clear it every time it comes up... it stays off for about 3 tanks of gas.

 

Hope this might help, after replaceing the purge valve and vent solinoid,
and charcole canister, and the gas tank pressure sensor, my fix was the the rubber hose from the firewall to the purge solinoid on the engine, I picked it up at the local salvage yard
for free.
Robert