that's the code im throwin and what i need to fix to get my car inspected. now can someone please shine some light on this for me. break it down really well too. questions: where is it? if i replace it, how much does it cost? can i do it myself? what does it do exactly? Anything i should check before i go buy a new one?
any help would be greatly appreciated

i also have a code for "O2 sensor circuit slow response (bank 1 sensor 1)" i plan on checking the O2 sensors to make sure all the connections are good and they are screwed tightly, but which sensor is it exactly? i'm figureing the front most on the y-pipe, help me please

 

anyone????

 

What is the CODE in DIGITS (how many long flashes, how many short)? I will try to look this up and help you.

 

code is 0704 or OBD II is P0450
thanks

 

bump. i really need some help with this guys

 

The EVAP control system pressure sensor detects pressure in the purge line. The sensor output voltage to the ECM increases as pressure increases. The EVAP control system pressure sensor is not used to control the engine system. It is used only for on-board diagnosis. This is from the FSM. The sensor is locate by the charcoal canister under the car. Malfuntion is detected when an improper voltage signal from EVAP control system pressure is sent to ECM. Some things to check for. Harness or connections. (the evap control system pressure sensor circuit is open or shorted). EVAP control system pressure sensor. EVAP canister vent control valve is stuck open. Hope this helps.

 

whoa man i got about half of that. so i get what to check and what it does, but it's still a little confussing. well first off, what does EVAP stand for (assuming it's an accronym)?
I was looking in my haynes manual and the only diagram of where the EVAP is i could see showed it on the top to the left of the filter just behind the battery. so it is underneath? and say the control valve is stuck open, can i just close it and hope it works or is there another course of resolution? is there any circumstance thati'll have to replace it?

i really do appreciate your help

 

the control valve is on top of the manifold its the biggest piece up there. but the trick to that is it MAY NOT be that part. there are several parts that work with that valve if one goes out it will throw code. us 98's are notorious for this problem ive found out. ill try and find some more info for you later. first check the faq's see what you find there.

 

I had a EVAP value issue a year ago and it turned out to be nothing. Make sure all your connections are tight and/or plugged in.

 

ok so i didn't get a chance to go through my haynes book tiil yesterday and ended up spending about six hours ****in with my car. so i checked the charcoal can and all the gas lines and return lines that run from it and there are no leaks. i checked all the wiring connectins there and made sure they're good. so i then checked my o2 sensor (cuz of the other code) and turned off my cel. now my question is how long/ far do i have to drive before the code come back on and i can get my car run at the emissions joint?

 

the light will come back on in about a day or two if there is a real problem. if not its fine. what i would do is go get the emmissions NOW while its off, then take it to a nissan dealer so they can CLEAR the ecu. they can also tell you how many times the evap has been a problem. just pay the $90 or so for the ecu check so you can have some peace of mind.

 

well ****. its back on. i literally drove less than 6 miles. i think i'm just takin it to a shop to get it fixed. i have an OBD II print out of what the codes are so i don't think the dealership reader will give me a different reading. thanks for all your help guys and i'll post up and let you know what i find out

 

My light came on giving my a PO1447. I found the hose coming from the EVAP control system pressure sensor to the plastic Y-piece broke. So check all your connections prior to going in too deep.

 

ok good news, no more EVAP control system pressure sensor malfunction code and no more o2 sensor code, they both went away. now i have another EVAP code, 0215, which is the EVAP control valve is closed. so obviously my question is now how to open it

 

My next step would check for charcoal in the system.

 

Your evap control valve is located right infront of the charcoal canister. Its 2 be known 2 fail due do insects clogging it. Nissan corrected this by selling a revised inlet elbow connector with an integral mesh 2 protect harsh items from entering. i personally think its ur control valve thats clogged, so i'd check that out. If its not that, then its ur canister for sure.

 

on my 95 I had to replace the EVAP control solenoid because of similar codes being thrown. When mine went, I could hear a hissing sound coming from behind the rear wheel on the drivers side. When I opened the gas tank and let the pressure out (in?), the hissing stopped. Itwas about 100bux for a new solenoid from the local dealer. Ebay probbably has it muuuuch cheaper!

Have a look at the hoses around the carbon cannister (behind rear d.s. wheel) as well as the engine side stuff indicated above. In my experience, the rubber hoses are much more prone to failure than any other parts.

 

ok guys thanks. i'll check, and hopefully fix it

 

Im having the same issuse with EVAP the valve and cuircuit are both malfunctioning.