Evap Codes

[Patrick82]

Hello, I have a 2001 Pathfinder with high milage 235,000 I just replaced the alternator (not fun). My heck engine light has been coming on quite frequently and they are all evap codes with the exception of 1 and that is an 02 sensor. The codes are P0441-Evap not functioning correctly, P0455-Evap leak, P0140- O2 sensor bank 2, and P1491-Vacuum Cut Valve Bypass Valve-. I guess my question is where do i start? and if I need to get this fix how costly will it be? I have get my inspection done and I live in New York with emmsions tests. Thanks!

[Towncivilian]

Replace the gas cap with an OEM sensor to begin with, it may solve your EVAP code.

P0140 is a rear oxygen sensor high voltage malfunction and is not critical to engine operation. Replace it with this Bosch OE-type O2 sensor from Advance Auto Parts - you can purchase it for $52.99 before tax if you order online using discount code VISA and pick-up in store. Bosch is the manufacturer for the original O2 sensor. You will require a 22mm or 7/8" oxygen sensor socket for replacement.

See this post for possible causes regarding P1491.

[Azndjay]

i had the same codes as you ,except mines end up being fuel pressure reg and fuel damper.

evap cannister is easy to replace if you go down that route , one word of warning . You might want to use a impact or cordless impact wrench for the bolts holding the canisters. Why? so the bolts don't break . some do, some dont something to think about while down there

[Patrick82]

Thanks guys just replaced the Vacuum Cut Valve Bypass Valve lets see how it goes. See how many more codes I can get to pop up. Ahh

[Patrick82]

Now I'm getting a p0446 code anybody know where to go from here?

[Towncivilian]

The FSM does not list P0446, are you certain that's the correct code?

[Patrick82]

Yep that's why I'm confused. The generic code is evaporating control systems.

[Towncivilian]

Try replacing your gas cap with a new OEM one.

[Patrick82]

Tried that too. Its going to the garage tomorrow!