There was a lot of mud caked on the hoses and components, so looking around and removing the canister resulted in a lot of dirt falling in my face. It is in an awkward place and Nissan charges about a 100. . Specifically the testing and replacement of the vacuum cut valve bypass valve. Here's a picture of both of them attached to each other: If you are absolutely sure that the electronic solenoid is doing it's job, and that none of the hoses are pinched or blocked, you need to check the vacuum cut valve for functionality. If you haven't thrown your old one away I would definitely check it.
The vacuum cut valve is then bypassed to apply intake manifold vacuum to the fuel tank. P1491 2001 Nissan Sentra Description The vacuum cut valve and vacuum cut valve bypass valve are installed in parallel on the purge line between the fuel tank and the canister. Want even more diagnostic training? This is what I emailed them. Blow air in port B and check that there is a resistance to flow out of port A. After taking a look at it, though, it seems a little more complicated than that since the sensor has no clear way of coming out of the tube.
This code covers both the vacuum cut valve bypass valve the electronic solenoid and the vacuum cut valve itself small round plastic valve. I had a 1491 error code drive me crazy. I have searched for a manual or a video showing exactly how to change the part or steps on how to do so. Blow air in port A check that air flows freely out of port C. It is located right behind the engine, look like a straw with a rubber cap on it.
It is about halfway between the fuel filter and spare tire on a little ledge bolted to the wall. That's where I was able to find the correct part number of 17372P. I then replaced the the valve cut bypass valve four hoses going to it with a used one from junkyard. Basically the same question I posted here. The coils packs can be seen mounted on the valve covers three each side, a small grey block held to the valve cover with a 10mm bolt.
Hope this helps; keep us updated about your advance. They also work well with one- or two-solenoid valve designs and work with direct current or alternating currents. Feel Free to contact me at FixYa. Commercial, heavy duty, custom, or off road vehicle use voids the warranty. The vacuum cut valve bypass valve is located on the same metal bracket as the vacuum cut valve. By making the mistake of topping off the tank just once, is it a problem that may get fixed by itself evaporation? This is only the first time that I put gas on the truck ever since I bought it. And it seems to have no effect on driveability.
Original proof of purchase is required. Sometimes, your car acts up and you panic wondering what can be wrong. Description: This post describes one of the diagnosis steps for the P1491 codes on a 1999 Nissan Altima. It's often a guessing game to figure out which part is worn and causing the problem. However, the most common cause of this code on nissans is the evap vent control valve. Blow air in port B check that air flows freely out of port D. You can locate it by looking for the charcoal canister which is a large, black square box on the drivers side of the gas tank, and then following one of the lines until you see a white cylinder with four tubes coming out of it.
Service Engine Soon light came on at around 65 miles, as usual. Vacuum lines should be checked for cracks or loose connections. It's possible that the valve wasn't really your problem, or that there is more than one problem. P1491 Vacuum Cut Valve Bypass Valve This is the code that the check engine light came out with. I couldn't really see above the ledge, but I noticed two rubber hoses around it that were not connected to anything, so I figured that must be the problem. Two of those hoses go to a solonid valve with a two wire electrical connection.
The vacuum cut valve bypass valve is a solenoid type valve and generally remains closed. The vacuum cut valve prevents the intake manifold vacuum from being applied to the fuel tank. Hey Joe, Sorry to hear that it didn't go as smooth as planned and that it didn't solve your code. But does this mean cleaning out the outside of the part or the inside, and where exactly? Our Nissan parts and accessories are expedited directly from authorized Nissan dealers strategically located all across the U. Hey Joe, Sorry to hear that it didn't go as smooth as planned and that it didn't solve your code.
I had a 1491 error code drive me crazy. No, it is fuel injected so the computer simply stops injecting. Luckily, on many occasions, it is a simple part such as a Nissan valve solenoid. Not sure where it is on that model;it will be attached to a hose assembly to let air from the crankcase bottom of the engine get sucked back into the intake top of the engine. The cover comes off and the white plastic piece is the vacuum cut valve bypass valve. This verifies the intake manifold vacuum. Took apart valve cut bypass valve popped the top off with small slotted screw driver and cleaned inside which had debris in it,seemed to be rust or small granules inside.
This applies to all Nissan Altimas which are 1998, 1999, 2000, 2001. Commercial, heavy duty, custom, or off road vehicle use voids the warranty. Catalytic converters cannot fail on there own and the original cause of failure must be repaired to prevent repeated converter failure. Plug port C and D with fingers. Took the Altima for a long drive about 80 miles , and P1491 is.