[aman74]

Hey there, my check engine light has come on. I took it to the shop and they said it was the evap system and ordered a gas cap from the dealer. I had asked if they could narrow it down with a smoke test and/or other diagnostic measures. They said they'd need to put a new gas cap on first since if that's bad it wouldn't let them narrow things down.

They also told me, after I got the gas cap from them, that E-Check in Ohio provides free gas caps if they test bad. This was rather annoying as I mentioned I was up for my E-check and that's what prompted my visit in the first place. I paid 27 bucks for the cap, does that sound right from the dealer? My only consolation is that it does seem to be a bit of a pain in the butt to find one with the tether on it and I don't think the universal tethers work with most aftermarket gas caps as they don't have a groove?

Well, my check engine light is back on, so clearly the issue is elsewhere. I'm bringing the car back tomorrow most likely. I'd like to know before I go back if there was indeed a way to diagnose this without getting the cap. I wasted time and money.

Thanks for your thoughts!

 

[i68k]

im not to familiar with e-check, but normally you get the tether line on the gas cap when it comes from nissan, im not sure of swappability for other years, i know my gas cap comes with a tether line. maybe your car originally didnt have one. for the smoke test, if they add pressure to the evap system, and you have a bad gas cap, it could possibly push fuel out the gas cap, so theyre doing it for safety, its probably procedure. it is rare that gas cap is actually the source of ses light.

do you know what ses codes you have? this would help narrow it down. also knowing your year/model b15. depending on the ses codes you have, its very possible to know what the source problem is without replacing the gas cap. if you only have a general small/large evap leak code and dont see/hear the vacuum leak, a smoke machine maybe the only way to find the source problem without throwing a bunch of parts it.

 

[aman74]

Thanks.

Sorry, I forgot to put my year/model. It's an 01 SE 2.0 liter.

I didn't get the code from them or autozone, I don't know much about it so didn't realize I should have asked. I'm no expert, but did think to kind of question if they could diagnose it and narrow it down further before just buying a cap. He started talking about the tests and depending on the code, etc... I believe them to be honest, but at the same time it honestly sounded like they just didn't want to take the time, since he said it would take a half hour or so.

He didn't mention safety.

I want to give the benefit of the doubt, but I also want to know I'm not wasting any money. Especially since they forgot to order the gas cap and I had to come back, etc...

 

[i68k]

well, like said, im not sure about getting free gas caps or reinbursements, maybe they know more about the e-check stuff. im sure getting you a gas cap is procedure for your follow up smoke test. remember, they are running a business, time is money. you could always make an appointment, so they dont forget about you.

whenever your ses light is on, you can goto autozone, or similar, and they will pull the ses codes for you. they usually will print the codes out for you as well. if you download the fsm (factory service manual), around here to download free somewhere, you can pull your codes the hard way without a scanner. the fsm also contains diagnostic procedures for airbag and abs codes along with many other service routines. if you have time, you could review them yourself.

you could download your fsm here:
allsentra.com/fsm
nicoclub.com/fsm

 

[aman74]

Thanks. I guess I'll never know for sure without the code. I'm bringing it back to the shop on Thurs., hope it goes well.

 

[i68k]

for evap situations, having the ses code is great, otherwise you could throw parts at it and never find the problem. dont forget, its not like we can look at the car in person. i can recommend you look around for loose or cracked vacuum hoses. also check your battery terminals are super tight, and theres no corrosion, make sure it has good ground. you could check you battery voltage motor on & off as well. just in case youre losing voltage, any random sensor could lose voltage and cause the ses light. otherwise like said, without the code, were blindfolded walking thru a cloud. hopefully you turn out well on thursday.

 

[audio1der]

I'd betcha its that crappy little sensor on top of the EVAP canister, the one which you couldn't possibly hope to undo without breaking both the mounting bolts. I did EXACTLY the same trouble shooting myself, and changing the sensor did the tru=ick. Mine has been held on by a generous bead of sensor-safe RTV sealant and 2 zip-ties for about 4 years.
I'm sorry, but I only have the FSM at work where I can't access photobucket to share any pics, and I've had a few to drick hha

PM me your email and I'd be happy to send ya a couple FSM pages that should help you fix it your self with a screwdriver.

 

[i68k]

...without breaking both the mounting bolts.....held on by.....2 zip-ties for about 4 years.

haha, same here. mine decided to crap out on me when it was like -10 deg outside. i was laying on 2inches of ice trying to change it, and breaking bolts didnt help. seems the zipties work better than the bolts that were there.

 

[aman74]

for evap situations, having the ses code is great, otherwise you could throw parts at it and never find the problem. dont forget, its not like we can look at the car in person. i can recommend you look around for loose or cracked vacuum hoses. also check your battery terminals are super tight, and theres no corrosion, make sure it has good ground. you could check you battery voltage motor on & off as well. just in case youre losing voltage, any random sensor could lose voltage and cause the ses light. otherwise like said, without the code, were blindfolded walking thru a cloud. hopefully you turn out well on thursday.

I'd betcha its that crappy little sensor on top of the EVAP canister, the one which you couldn't possibly hope to undo without breaking both the mounting bolts. I did EXACTLY the same trouble shooting myself, and changing the sensor did the tru=ick. Mine has been held on by a generous bead of sensor-safe RTV sealant and 2 zip-ties for about 4 years.
I'm sorry, but I only have the FSM at work where I can't access photobucket to share any pics, and I've had a few to drick hha

PM me your email and I'd be happy to send ya a couple FSM pages that should help you fix it your self with a screwdriver.

Ok guys, thanks for your help thus far.

I should have realized I could get a lot further by doing some research here and getting the codes. I'm just in a real time crunch, in the middle of a move and was worried about passing E-check.

Today was an adventure. I left the shop and couldn't make it to the E-check before the light came back on. I don't think he even reset it this time since it usually takes a couple days to come back on after a reset. I dunno though, maybe they had to do a reset when doing the smoke test?

I stopped at Autozone and got another test done and thought they could do a reset, but they said they aren't allowed to do it, so I went back to the shop and this time made it to the E-check in time. There was also a first trip to a different E-check station, but they didn't have the full set-up there and said since my computer was just reset and would need to settle in for awhile before they could do the test, they said I had to go to the full E-check station so they could do the actual exhaust test. What a hassle! Sorry, had to vent.

Ok, so the shop did the smoke test for 50 bucks. Which, after doing some reading seems to have been a wasted, along with the 25 dollar gas cap. Oh well, live and learn.

They said I need an evap canister and a purge valve to the tune of 500 some odd dollars. I did some googling and found an old thread on here:http://www.b15sentra.net/forums/showthread.php?t=142973

It seems that usually the canister is ok and you just need to get a new valve or clean the one you have possibly. I'm a bit confused about the valve. Is the Vent Control Valve the same as the Purge Valve the shop mentioned? I'm guessing so as some of the aftermarket parts call it either or.

My code from Autozone says P1440. I'm guessing since the smoke test showed a canister/valve issue that it's not the sensor? It also appears from the other thread that the canister is actually usually still good, but that shops just do the whole thing because the bolts are most likely going to break and then you have to rig a way for the valve to be installed. The valve is relatively inexpensive. I haven't found the canister yet and I think it may be a dealer only part?

Unfortunately I'm disabled now and don't know that much about cars anyhow, but it looks like in the past I could have handled this job. The upside is that I passed E-check at least and this can at least wait awhile. I may just find someone to help me with this in the driveway or something if the shop still wants 500 bucks.

Look forward to your thoughts, thanks!

 

[i68k]

like said, you can do the pedal dance and clear your codes without a scanner. when they do inspections, they usually see that it hasnt cycled enough tho.

the vent valve and purge valve are different pieces, at different ends of the car. the vent valve is the one attached to the evap canister, held on by 2 screws and has an electrical connector. the purge valve is near the intake somewhere, im not sure exactly where it is on your 2.0L, but it would branch off the intake. i believe both evap canister and vent valve are dealer only items, you can just get bolts ahead of time, most likely they will break on you. if you dont see the evap canister cracked or falling apart or something, its not usually the issue, its just a charcoal canister. the vent valve is usually problematic, last time i got one from the dealer is was $125ish.

your p1440, is just a general small evap leak. it doesnt specify where the leak is. so i cant say exactly where the problem is. just that a small leak is being detected. things like a new/cleaned pcv valve could help, also a dirty maf (use cnc maf cleaner only!!!) could also cause evap issues.

EDIT: im not sure how they can do a smoke test and not find the leak? the vent valve has a spring inside, that usually gets stuck open, causing a leak, sometimes cleaning doesnt work.

 

[aman74]

like said, you can do the pedal dance and clear your codes without a scanner. when they do inspections, they usually see that it hasnt cycled enough tho.

the vent valve and purge valve are different pieces, at different ends of the car. the vent valve is the one attached to the evap canister, held on by 2 screws and has an electrical connector. the purge valve is near the intake somewhere, im not sure exactly where it is on your 2.0L, but it would branch off the intake. i believe both evap canister and vent valve are dealer only items, you can just get bolts ahead of time, most likely they will break on you. if you dont see the evap canister cracked or falling apart or something, its not usually the issue, its just a charcoal canister. the vent valve is usually problematic, last time i got one from the dealer is was $125ish.

your p1440, is just a general small evap leak. it doesnt specify where the leak is. so i cant say exactly where the problem is. just that a small leak is being detected. things like a new/cleaned pcv valve could help, also a dirty maf (use cnc maf cleaner only!!!) could also cause evap issues.

EDIT: im not sure how they can do a smoke test and not find the leak? the vent valve has a spring inside, that usually gets stuck open, causing a leak, sometimes cleaning doesnt work.

I don't have time to elaborate, but wanted to drop in and say thanks and he did find a leak. I thought I mentioned it. They said the evap canister and purge valve needed to be replaced. I'm getting mixed up though because the part shown in the other thread is also listed as a purge valve all over the internet. I find it unlikely, but possible, I have leaks at both ends? When I saw the other thread I assumed the shop was talking about replacing the canister and the valve inside.

 

[i68k]

well thats good news. he might be referring to the vent valve when he says 'purge valve', thats what its called on most cars, except nissans and some other manufacture. if thats what he meant, the vent/'purge' valve is attached to the evap canister, which is what you were thinking. tell us how you make out afterwords, and feel free to make another thread if you have a different issue or problem. if you can relay the ses code when your light is on, even better! good luck!

 

[aman74]

well thats good news. he might be referring to the vent valve when he says 'purge valve', thats what its called on most cars, except nissans and some other manufacture. if thats what he meant, the vent/'purge' valve is attached to the evap canister, which is what you were thinking. tell us how you make out afterwords, and feel free to make another thread if you have a different issue or problem. if you can relay the ses code when your light is on, even better! good luck!

Not sure what you mean about "relay" the code? The light was on when I got the code from Autozone. I'm gonna call the shop today and I'll ask what code he got and also verify exactly what part he was speaking of.

The help here is much appreciated!

At least I've passed E-check and don't have to rush to get this fixed.

 

[aman74]

PM me your email and I'd be happy to send ya a couple FSM pages that should help you fix it your self with a screwdriver.

Thanks for the offer. Is it still available online? I had a bookmark at one point to a guy that was hosting it for awhile. I'm sure you guys know the site I'm speaking of. If that doesn't exist any longer I may have to take you up on your offer.

I just need to make sure I'm fixing the right thing first.

 

[aman74]

i believe both evap canister and vent valve are dealer only items, you can just get bolts ahead of time, most likely they will break on you. if you dont see the evap canister cracked or falling apart or something, its not usually the issue, its just a charcoal canister. the vent valve is usually problematic, last time i got one from the dealer is was $125ish.

Do you know what length of 10mm bolt I should get.

I'm seeing the vent valve and canister as aftermarket parts on RockAuto etc. He said dealer only as well and you are too, so I'm wondering if I have the right part. The valve runs about 40-50 and the canister almost 200!

 

[JudoJohn]

Rockauto is a good place to get parts. as for your bolt-- when you say 10mm, are you talking about the size of socket that goes over the hex, or diameter of it? 10mm is a LARGE diameter bolt. if the first one, then it is more likely 5 or 6 mm.

 

[i68k]

relay - meaning next time you have a problem, and your ses light is on, 'relay' the code to us, so we can help you easier.

the entire fsm is a free download, try these:
allsentra.com/fsm
nicoclub.com/fsm

i dont know the length of the bolts. im not sure about the dealer only limitations, when i got mine, it was a dealer only item. you can check places like rockauto, they may have what you are looking for. check for rockauto on this site, we might get the small discount, i know b15u gets like 5% off. it might not be dealer only anymore, considering your car is over 10 years old, last i remember paying like $125ish just for the vent valve at the dealership.

the best place for me to get bolts is at like home depot, or lowes. just bring your bolts and find one similar in thread and length, the head doesnt really matter as long as you have a tool for it. for these bolts, i would find a stainless or galvanized bolt, so it doesnt rust to crap so easy.