CEL P0446 in 97 Maxima

[fmwater]

Greetings,

I am the proud owner of a 1997 Maxima. Recently, I was face with a spate of CEL codes to correct. Chief among them were a code of the knock senor and this one. I disassembled, cleaned, lubed and tested the solenoid adjacent to the purge canister behind the right rear wheel well. When I applied 12 VDC to the solenoid leads I heard clicking. I presume this means the solenoid is working. I also replaced the tubing that connected the solenoid to the tank etc. After completing this step, I reset the diagnostic code, only to have the code reappear almost as soon as I began driving.

Would some kind soul tell me what the next step(s) is/are? I have looked high and low for a troubleshooting guide in this forum and maxima.org to no avail.

Thanks very much!

Frank

[carmo]

P0446 is a vent control valve code. I think. If the car codes almost immediately, that sounds like the computer isn't seeing the part plugged in. You usually have to drive for some time before the computer will use that valve. If this is the code I'm thinking it is, the control unit only uses that valve to make sure the system (evap) is leak free. While driving down the road the car will close that valve to seal up the system and use engine vacuum to well pull a vacuum on the entire evap. system. The control unit will then look at the system pressure sensor to see if the vacuum holds. If the vacuum holds for the specified period then the vent valve is opened and the system resumes normal operation. Since it is coding immediately, this tells me that maybe the pressure sensor is seeing a vacuum reading when it shouldn't. The control unit thinks that valve is stuck closed. Check for a blockage in one of the hoses. Sometimes spiders will crawl into those vent tubes a block them up. Good luck

[carmo]

Oh! and welcome to Nico.

[SteveTheTech]

Hey there and Welcome to NICO!

Carmo is pretty close the vent control valve allows vapor flow from the carbon canister to be introduced into the intake plenum. The pic below is the ESM explanation of what the Purge Control Valve does.Given the hear it may be time to replace it.

Note: I would also recommend getting a new carbon canister, given the year and high probability of damaging the old one during the replacement.