# evap OBD code



## lholler (Sep 15, 2013)

1999 Nissan Altima engine light is on Code is coming up as P0446- Can someone help me with this? he car needs to be inspected by end of September and need to know what part I need to replace. Gas cap is on tight. Tried shutting light off, it only comes back on which tells me it needs repair to be inspected.

Any insight would be appreciated..

Thank you


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## smj999smj (Jan 1, 2006)

There's no way to tell you if there is a failed part, leak or wiring issue that set your code with going through the factory service manual diagnostic procedure for your specific code. That said, the majority of these codes are set by a bad EVAP vent control valve, which bolts to the back of the EVAP canister. There have also been a few canister failures, which result in pieces of charcoal being released into the EVAP system. This can be checked by removing the EVAP canister and taking off the vent control valve. Then, shake the canister over some paper and look for tiny bits of charcoal falling out of it.


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## lholler (Sep 15, 2013)

Ok, so we changed the evap vent canister, and turned off the engine light. She drove it to the dealer this mrng to get it inspected and the light came back on. This time there is no code to go along with it. The service guy cleared the light, it came back on before she got back home. Still no code. Is this because the computer doesn't realize the part was replaced? We are going to disconnect the battery when she gets home tonight and see if that solves the problem. Any other suggestions????


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## smj999smj (Jan 1, 2006)

As far as the ECM, it doesn't ever know if a part was replaced or wasn't...it just monitors data and sets a code when it detects a problem. If the code was properly erased and came back on, there should be a stored code. It's odd that one is not showing up unless you have a faulty ECM.


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## lholler (Sep 15, 2013)

How do you properly erase the code? All they did was clear it with that little thing they plug in to read the code..


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## smj999smj (Jan 1, 2006)

That should have cleared it.


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## jayray (May 24, 2010)

New York State. Last year I replaced the cats (4) and spent enough money to get a waiver. This year it is the evap cannister and the check valve. Pathfinder runs really great. I hope this time it will pass for under 500. I know these things run forever if you keep oil in them. 2002 has 150k and my only issue is NYS inspection.


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