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Discussion Starter · #1 ·
Truck is AMAZING in comparison with the 1st gen. Nissan took some big steps in those years between my models.

I am having a P0448 code come up. I have done some research ion here and other forums but don't know what my friend who was the PO could have missed.

This is the process he went through before selling it to me:

"the code popped up it was for a vent issue.
With that I pulled the canister and other parts down and replaced the purge valve, the old one was sticking.
It went off for a bit but came back as a leak in the system, I assumed I put it together wrong so I pulled it, cleaned it up and put it back.
Code was still on.
Pulled it, checked all parts, even weighed the canister to see if it was full or not.
Same code still popped up but this time with the description that there was a fault in the circuit.
Pulled the damn thing out again, checked the sensors and the connections, cleaned both parts, checked the fuses, and checked the wiring (didn't see any wiring issue but I may have missed it, wiring isn't my strong point in automotive repair).
All looked good otherwise, and aside from just replacing pieces of the system one by one I couldn't find a fix. "

Any ideas on where I should start to check for a fix on this?
 

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Any ideas on where I should start to check for a fix on this?
I recently had the P0448 code pop up. I removed the evap vent control valve and cleaned it out. It might be easier to get access to the valve if you remove the entire evap canister from the truck. Gently disconnect the hoses and wires connected to the canister. Then remove the one bolt holding the canister to the frame.

There are two electrical connections going into the canister. The connector towards the front of the truck is the vent control valve, I think. The connector towards the back of the truck is connected to somthing labeled "purge." To remove the valve, rotate it counter clockwise about 45 degrees until it clicks. Then you can wiggle it out towards you. Use compressed air to blow out all the dirt trapped in the valve. I used canned air since i dont have access to an air tank. Once it's free of dirt or what have you, the little "piston" inside should be free to move. It's held in place by a spring, but if you shake the vent control valve up and down, you should be able to hear the piston moving within the cylinder. You can also verify the valve is working by connecting it to a 12v power supply. You should see and hear the valve engage. (I didnt do this.)

Reinstall the valve into the canister and put everything back together. When you start the truck again, the P0448 should be gone.
 

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Discussion Starter · #3 · (Edited)
I tested the valve OK over the weekend. Canister was blown out, and didn't weight a ton (did not use a scale, but I'd be amazed if it was over 4.4lb).

I blew into the 3 hoses I disconnected, and only 2 of them would allow airflow with the truck off.

Picture below has hoses labeled 1-2-3. Only 1 and 3 allowed airflow. 2 was not flowing at all.
 

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