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Jay, Nissan Technician
Category: Nissan
Satisfied Customers: 20100
Experience:  20+yrs experience with Nissan & Infiniti Trained & Certified.Currently still working for Dealer
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1997 Nissan Pathfinder: check engine light..emissions..the sensors

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Kat, I have a 1997 Nissan Pathfinder and the check engine light has been on awhile. My mechanic said it is due to emissions and he cleaned the sensors and cleared the light. The light came back on within a day. He checked the codes and they were the same. He told me he would look into it...this was 6 months ago. Now the service engine soon light is on. I took it to AutoZone and here are the codes:

P0450 (again)

I took the canister off and checked the evap vent control valve as you described in a post a couple of years ago. The valve clicks when I applied the 12V to one pin and grounded the other, so I know it is okay. However, charcoal was coming out of the canister through the opening on the valve where the hose goes and vents off to atmosphere. It may be coming out of one of the other hose nipples as well, but I reinstalled it until I can figure out what I need to do.

What do you recommend? I am in a small town so the local Nissan dealer charges an arm and a leg for everything. My FORMER mechanic lost my business due to his lack of urgency to get to the bottom of this. Thanks!
Hello and thank you for using

If you removed the evap canister, and pellets came out. Go all the way up under the hood to where the evap line goes, and disconnect it there. If you find pellets in that hose also, you will need to replace the evap canister and vent control valve. Then disconnect all hoses and blow them out to get the debree out of the lines. Once you clear the lines, and replace the vent control valve and evap canister, then you clear the light and recheck the system.

If you have any more questions, please feel free to ask. Thanks Jay!
Customer: replied 8 years ago.
Jay, thanks for the reply.   I just checked and there is indeed a BUTT LOAD of charcoal all the way up. Do you know if the aftermarket canisters are decent or should I just go with Nissan's? I found a place online ( that will sell me the canister for 141.70 and the vent control valve for 95.88 plus shipping. I can get the canister aftermarket for about $50...but will it fit correctly? Also, since I tested the vent control valve and it was okay, why would I need to replace it? Thanks!
I would stay with the Nissan, but if you want to try the after market thats up to you. Allot of times after market parts don't work like the factory parts and could cause codes like you didn't repair it. Anyway, just double check the valve. I have seen the valve click but the mechanical plunger not move. Do a visual and mechanical check to make sure. It just clicking doesn't always mean it's ok. Just double check it. If everything works ok with the valve, then replacing the canister and checking the entire system and cleaning it is your next step.

If you have any more questions, please feel free to ask. Thanks Jay!
Customer: replied 8 years ago.
Thanks, Jay. One more thing....I looked at the drawing under the hood which shows the evap system as it pertains to the engine compartment. Will the evap canister purge cut valve or the evap canister purge control valve be damaged if charcoal is up in that area? Is there a way to test these valves?
I would remove them and try to clean them. It is possible, but you won't know till you get it all cleaned out. When the canister blows up and contaminates the system, it's a mess. It could take a couple times before you get it all cleared up. You will keep finding debree if not cleaned correctly and lines blown out to clear them.

If you have any more questions, please feel free to ask. Thanks Jay!
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