shurik355 Posted May 10, 2012 Share Posted May 10, 2012 Hi guys Im new here, =) I have a 98 Infiniti qx4 which is same as a pathfinder. And I got an Engine light which throws the codes P0440 and P1448 and I know that this a for a small leak in the Evap system. My car also sometimes stalls after a start, and takes a couple tries to make it start with accelerating. It also did shut off on me on the highway while I was driving a couple times. Not common but it did happen before. After that I cleaned my Evap lines. Blew compressed air through the lines by making sure there is no pieces of charcoal. The lines turned out to be clean. While the cleaning the lines I had the battery disconnected so the engine light was gone after I was done. So after that the car ran ok for a week and then the engine light came back AGAIN. The car started having rough starts again but never stalled on me while I was driving since I cleaned the lines (but maybe it's just a matter of time) Any idea what this might be??? Bad Evap control valve, not opening properly or what??? Link to comment Share on other sites More sharing options...
918pathy Posted May 11, 2012 Share Posted May 11, 2012 If I am not mistaken I think the P0440 code is your catalytic converter, I could be wrong so dont quote me (LOL)I am still learning, but I am sure of the experts will chime in and corrrect if i am wrong Link to comment Share on other sites More sharing options...
Towncivilian Posted May 11, 2012 Share Posted May 11, 2012 P0440 is "EVAP CONTROL SYSTEM (SMALL LEAK) (NEGATIVE PRESSURE)". Try replacing your gas cap with a new OEM one to begin with. P1448 is "EVAP CANISTER VENT CONTROL VALVE (OPEN)". Make sure all of the vacuum hoses for the evap canister next to the rear right tire are securely connected and none are clogged. Link to comment Share on other sites More sharing options...
devonianwalk Posted May 11, 2012 Share Posted May 11, 2012 To add to Towncivilian's gas cap recommendation, make sure that you are turning your current gas cap until it "clicks". You would be surprised how that could trigger the SES indicator. Link to comment Share on other sites More sharing options...
918pathy Posted May 11, 2012 Share Posted May 11, 2012 Sorry that was my bad P0420 is a bad cat. Link to comment Share on other sites More sharing options...
shurik355 Posted May 12, 2012 Author Share Posted May 12, 2012 (edited) P0440 is "EVAP CONTROL SYSTEM (SMALL LEAK) (NEGATIVE PRESSURE)". Try replacing your gas cap with a new OEM one to begin with. P1448 is "EVAP CANISTER VENT CONTROL VALVE (OPEN)". Make sure all of the vacuum hoses for the evap canister next to the rear right tire are securely connected and none are clogged. Yeahh I really doubt that it's my gas cap, but I guess worth a try. I know i tighten it really good. Seem like it seals really good. Anyway I did clean all my EVAP lines how it was described here http://www.aa1car.co..._ntb00-085a.pdf I didn't check the water seperator though. Maybe it's mine Evap control valve stuck open like some ppl describe but i don't know how to test it. And the bolt that tightens it to the canister is rusted and I don't know that I'll be able to take it off to test it or inspect it. I really don't want to replace the canister with the valve sensor just because the sensor can't be taken off =( And yes I did check the hoses for the cracks and any kind of damage but all seems like ok. Edited May 12, 2012 by shurik355 Link to comment Share on other sites More sharing options...
Towncivilian Posted May 12, 2012 Share Posted May 12, 2012 Just because it seems to seal fine doesn't mean it's working properly. It's cheap, replace it anyway. See EC-406 for a diagnostic procedure for the evap vent control valve: http://www.nicoclub.com/FSM/pathfinder/1998_Pathfinder/ec.pdf Link to comment Share on other sites More sharing options...
shurik355 Posted May 13, 2012 Author Share Posted May 13, 2012 thanks for the info above! That's a good link. I'll try testing my Evap vent control valve and the canister. So to clear things up of how to check the Evap control valve. I can use a battery jumper box to test it right? And when I test it what exactly the valve suppose to do and not suppose to do???? and how do I see if it's good or not??? Link to comment Share on other sites More sharing options...
shurik355 Posted May 15, 2012 Author Share Posted May 15, 2012 ^^^ anyone can clarify the above step for me? Link to comment Share on other sites More sharing options...
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