I bench tested the canister vent valve and the purge solenoid valve and they BOTH open/close with 12 volts power. Hoses seem to be in good shape, nothing obvious that is. Undercarriage of my car is super clean, no rust, no dust. Gas cap is not cracked. The P0447 code described as an 'open circuit.' Other codes thrown as well, but I think these are the culprits. Car operates normally otherwise, though I sometimes catch a whiff of fumes upon start up at the rear, not inside. Any advice?

 

the other code you have is your problem. EVAP gross leak. you either can try caulking all around the sensor at the canister , i fixed a leak for 5 years doing that no new parts, i eventually had the actual canister go on me though 5 years later.

to be sure and done with this problem once and for all its best to replace evap canister, evap sensor at canister, and 2nd evap sensor on the engine bay (keep in mind OEM is king when it comes to sensors on these cars)

evap codes are a pain in the butt. and if you dont want to deal with this again and again trying different things then you should just replace what I mentioned above. if you don't want to do all that, and you can be patient and try each thing individually go ahead it may not be bad but will be a lot of trial and error and time

also I replaced the engine side evap sensor with Dorman, and it was faulty from the gate, and made me circle around and have to triple check everything I already did because I trusted a new part was good to go, but it wasnt. replaced that part with OEM nissan sensor and probelms went away.

search around there they may be 100 threads on evap issues

 

also - to dormans credit they refunded me entirely. our cars are just finicky with sensors.