I looked this up on troublecodes.net (searched here to find that site-- thanks!)

It says this is Vacuum Cut Valve Bypass Vale. (I assume that last thing should say "valve", but I'm just copy/pasting from their site)

Car doesn't run funny and the light doesn't even always come on. Any ideas on how to fix this?

Thanks in advance!

Wow that is a weird one. I looked it up in service manual....

Basically it is a valve that keeps vacuum from intake manifold from being applied to fuel tank. It is supposed to be always closed except for diagnosis mode.

Says error code is for when valve is "not functioning properly".

Then gives laundry list of culprits for why it wouldn't, and only way to test is with consult- II or gst unit.

I don't know how to help you really, but that explains the problem hopefully. I guess you could look over EVAP system and see if lines are clogged or if valve's wires are cut.

thanks for the info. I'll do some looking, but with the high being 8 today, I may not spend too much time :)

it hurtst to say, but this could be a dealer problem :(

Uh yeah... 8.... uhm it can wait to be looked at.

Basically it isn't that important of a code imo. If you notice any drivabilty issues then it becomes an issue, but it just sounds like a clogged vent or faulty wiring/valve.

And I didn't want to say it... but yeah I think even I would take that to dealer since they may have a clue what it could be.

Sorry I couldn't be more help.

my error code said p1491. but its not any vacuume valse it says Manufactur Controle Emissions Controle. any idea..

its on a 01 sentra se w/pp