P1456 Solved

[gcjazz12]

I'm keeping my fingers crossed but it looks like I've finally solved the P1456 code on my 2002 QX4.

I tried the gas cap thing - new cap, turn tight three clicks etc... and that did not make the code go away.

On the drivers side rear of the vehicle there is a black canister that has 3 hoses running to it. I snapped off all bolts holding this canister to the vehicle which then had to be drilled out (rust is terrible on this vehicle). Then I tried replacing the evap valve that is connected to the canister. Both bolts attaching the evap valve to the canister snapped off as well. The evap valve was about $125 at the Nissan dealer. I tried running it like that for a few days (taped it on to the canister) - still getting P1456 though. So, ordered a new canister from RockAuto. Put the new evap valve on the new canister - been driving for a few days, still getting my P0430 but the P1456 seems to have disappeared. Also, when putting the evap valve back on I didn't get the electrical sensor on tight and it started throwing a P0447. Interesting. So, snapped it on tighter and cleared the code and the P0447 didn't return. I heard a click when I knew I had it on tight enough. In this process learned a little bit more about how the hoses and clips worked... I was able to move the clips by using vise-grips and got the hoses off the plastic vents on the canister with a flat head screw driver, slowly prying them off the vents like you would open a can of paint.

You can see inside of the charcoal canister if you take the evap valve off. The new canister looked blue on the inside and the old canister was black.

If it hadn't had been for the bolts snapping off, this was a pretty easy fix and would have done it along time ago. The trouble with P1456 is that it can be so many different things, but it appears the canister wasn't functioning properly anymore in this case.

Hope this helps someone with the same issues.

[audtatious]

Awesome, thanks for documenting!

[Jonbrew]

I had the exact same cracks I took a Dremel tool and removed the threaded bushing and the dirty cracked plastic. Using Jb weld I patched the crack after cleaning with acetone then reinstalled no more leak

[cmx378]

I'm keeping my fingers crossed but it looks like I've finally solved the P1456 code on my 2002 QX4.

I tried the gas cap thing - new cap, turn tight three clicks etc... and that did not make the code go away.

On the drivers side rear of the vehicle there is a black canister that has 3 hoses running to it. I snapped off all bolts holding this canister to the vehicle which then had to be drilled out (rust is terrible on this vehicle). Then I tried replacing the evap valve that is connected to the canister. Both bolts attaching the evap valve to the canister snapped off as well. The evap valve was about $125 at the Nissan dealer. I tried running it like that for a few days (taped it on to the canister) - still getting P1456 though. So, ordered a new canister from RockAuto. Put the new evap valve on the new canister - been driving for a few days, still getting my P0430 but the P1456 seems to have disappeared. Also, when putting the evap valve back on I didn't get the electrical sensor on tight and it started throwing a P0447. Interesting. So, snapped it on tighter and cleared the code and the P0447 didn't return. I heard a click when I knew I had it on tight enough. In this process learned a little bit more about how the hoses and clips worked... I was able to move the clips by using vise-grips and got the hoses off the plastic vents on the canister with a flat head screw driver, slowly prying them off the vents like you would open a can of paint.

You can see inside of the charcoal canister if you take the evap valve off. The new canister looked blue on the inside and the old canister was black.

If it hadn't had been for the bolts snapping off, this was a pretty easy fix and would have done it along time ago. The trouble with P1456 is that it can be so many different things, but it appears the canister wasn't functioning properly anymore in this case.

Hope this helps someone with the same issues.

Hey @gcjazz12, I know this was an old post but I'm hoping you're still active on this forum/site. I'm having issues with a P1456 DTC that I can't seem to get rid of on my 2002 Nissan Pathfinder Chilkoot. I've replaced the gas cap with a Nissan one, cleared the code, but it came back again. I took it to my local Nissan dealership to have it diagnosed and they smoke tested the EVAP system but said they couldn't find the issue, except they did see there was some corrosion inside the fuel filler neck. I know about the fuel filler neck recall which covered up to the '01 Pathfinders, but anyone with an '02 - '04 are S.O.L. for getting Nissan to replace the fuel filler neck due to the same issue. Anyways, I went to my local pick 'n pull and found an '04 Pathfinder and took out the fuel filler neck, which was in much better shape than mine and had no visible corrosion on the inside of the of the upper tube. I replaced this '04 fuel filler neck hoping it would resolve my P1456 DTC... but after doing so and clearing the code, the damn code came back. Since your post is a few years old, the images you inserted in your post are no longer available. Would you be able to send me those images or repost them? Just trying to see what it was you replaced. Thank you!

[VStar650CL]

When you took it in, did they drop and weigh the evap canister? My guess is @gcjazz12's canister was oversaturated and full, and probably yours is too. P1456 generally implies a pressure vagary during EONV and not a leak. The culprit will usually be a full canister or an obstructed bypass tube.

[cmx378]

When you took it in, did they drop and weigh the evap canister? My guess is @gcjazz12's canister was oversaturated and full, and probably yours is too. P1456 generally implies a pressure vagary during EONV and not a leak. The culprit will usually be a full canister or an obstructed bypass tube.

No, I don't believe they did so. See image of the invoice below:

Should I bring it back in and ask them to do so? However, would they even know what it should weigh? Or, would I need to provide them with (a new) one to compare my current one against? I'll probably incur another diagnostic fee... or should I just order a new EVAP canister and do it myself (latter reason was why I was looking for the images in the OP)? Alternatively, I could probably head back to the Pick 'N Pull and take off the EVAP Canister on the '02 they have there (unfortunately, the '04 I pulled the fuel filler neck from is no longer there) and then swap that with my EVAP canister to see if the P1456 stays off after clearing it again. Of course, there's no guarantee that EVAP canister didn't experience the same P1456 DTC before it went to the Pick 'N Pull. I'm also glad I didn't get them to replace the fuel filler neck... at a cost of $990.32... which wouldn't have "rectified my concern"...

This problem comes at a real bad time for me. I'll be moving to Europe at the end of this month and trying to get this P1456 code to go (and stay) away, before selling my Pathfinder to a work colleague who's interested in buying it. So, time is of the essence for me to get this fixed (not to mention all the other things I need to do to prepare for my big move...).

[VStar650CL]

Aside from rusty screws the canister isn't hard to replace, but on an '02 there's a really good chance you won't get the smaller screws out without breaking at least one. So if you DIY it, it's a good idea to buy a new bracket along with the canister (the larger screws that hold the bracket to the underbody rarely snap). RockAuto should have the canister for less than half the price of OE.

[cmx378]

Ok, thanks for the advice. I'm not sure where the smaller screws you're referencing are until I get back underneath the vehicle again, but I'm praying it's nothing that can't be quickly, easily, and cheaply replaced. Is the bracket only available through Nissan? If not, do you have a part number for the bracket, by chance? Would you happen to know roughly how long it will take for RockAuto to ship the EVAP canister to (Alberta) Canada? Time is against me...

And yeah, RockAuto has the part for the cheapest at $190.81 CAD (excluding tax, shipping/handling, duties), compared to PartsAvatar.ca ($272.58 CAD), TheWrenchMonkey.ca ($282.55 CAD), NAPA Canada ($434.39), and I don't even want to bother checking with my local Nissan "stealership" for their pricing. I already know how inflated they are with my fuel filler neck research...

[VStar650CL]

I have no idea how long it takes Rock to ship to Canada. USPS First Class to Canada usually takes about 10 days and UPS ground about 6 days, if that helps you. There are three 6mm screws which hold the canister to the bracket and three more 8mm's that hold the bracket to the car. The 6mm's often rust out hopelessly and snap no matter how careful you are. But honestly, if you're that pressed for time, I've seen backyarders go tens of thousands of miles with evaps hung on long zip ties. It just needs to be secure, not fancy. Here's a vid, this guy has to fight with the same screws I'm talking about:
https://www.youtube.com/watch?v=9C8QuCu68dM

[cmx378]

I just did a quick "test" checkout from RockAuto and if I place the order today, and with delivery using FedEx, then the "expected" or "estimated" arrival date would be July 21st... so that's somewhat hopeful. Also, when you were talking about that bracket which holds the canister up, was that the bracket (which looked practically new) the guy pulled off from the pick 'n pull (and holy crap were there a lot of Pathfinders and QX4s he had to choose from! Lol, it's slim pickings over here in Edmonton, AB, Canada!), from the YouTube video? (And thanks for the video too!)

I'm going to jack the vehicle up today and start spraying penetrating fluid on all the screws/bolts. I'm probably going to head to the pick 'n pull (again) and try taking off the EVAP canister on that '02 Pathfinder they have there (and maybe even the bracket, if it comes off easily; however, the guy in the video said he took the bracket off a '99 Pathfinder, so would a bracket from a '98 Pathfinder also be interchangeable with an '02?). Although this requires spending more time (that I somewhat don't really have), it will help prepare me in taking off the EVAP canister on my Pathfinder, just like I was able to learn from taking off the fuel filler neck.

Also, since I'm pressed for time, would you think it would be a good idea to take my Pathfinder in and have them replace all the screws/bolts for the EVAP canister for me? That way, they have all the tools to get it done quickly and then I can just order the canister and quickly swap it in, without having to deal with rusted screws/bolts. I'm guessing it should take about an hour's worth (@ $170/per) of work for them?

[VStar650CL]

when you were talking about that bracket which holds the canister up, was that the bracket (which looked practically new) the guy pulled off from the pick 'n pull (and holy crap were there a lot of Pathfinders and QX4s he had to choose from! Lol, it's slim pickings over here in Edmonton, AB, Canada!), from the YouTube video? (And thanks for the video too!)

Yep. The reason he pulled a less-rusty one from the JY is because it's easier than drilling the old one and trying to restore threads.

the guy in the video said he took the bracket off a '99 Pathfinder, so would a bracket from a '98 Pathfinder also be interchangeable with an '02?

Yes, I'm pretty sure it's the same bracket all the way through '06.

Also, since I'm pressed for time, would you think it would be a good idea to take my Pathfinder in and have them replace all the screws/bolts for the EVAP canister for me? That way, they have all the tools to get it done quickly and then I can just order the canister and quickly swap it in, without having to deal with rusted screws/bolts. I'm guessing it should take about an hour's worth (@ $170/per) of work for them?

They're gonna charge you for rusted bolts and then tell you you need a new bracket. Don't bother, hang it with zips and then replace the bracket and screws when it's more convenient.

[cmx378]

They're gonna charge you for rusted bolts and then tell you you need a new bracket. Don't bother, hang it with zips and then replace the bracket and screws when it's more convenient.

Yeah, but I figured they would be able to get the rusted bolts/screws off quicker than I could, so I would be willing to take that "hit" in the interests of saving time. As for the bracket, if they tell me I need a new one, then I could tell them I'm just going to zip-tie it (but even before I bring it in, I would tell them to be very careful not to break the bracket and if they do, then to use zip-ties to secure it). Unfortunately, I won't have the opportunity to replace the bracket and bolts/screws at a more convenient time my flight departs for Europe on July 31st). I'm already in the process of selling the vehicle to my co-worker, but it's this damn P1456 code that's holding everything back from closing this transaction...

Also, I don't suppose I could heat these rusted bolts/screws up in order to help break them free, would I? Are the mounting tabs on the canister made of plastic or metal? Or would the hoses be too close to the bolts/screws in order to heat them up?

[VStar650CL]

Heat may work, along with a good soak in PB Blaster or WD.

[VStar650CL]

Or you could hang it with zips and tell your co-worker to replace the bracket at his leisure. It certainly won't affect the way it runs.

[cmx378]

Ok, I just wasn't sure what the vapor canister was made out of (plastic or metal), specifically the mounting tabs that the screws/bolts go through.

RockAuto has two different brands of vapor canisters: SMP ($190.81 CAD) and WVE ($200.17 CAD). Since the price difference is negligible, should I go with the more expensive one (in the hopes that it may be of better quality)?

UPDATE #1: I was thought I would also search eBay.ca and Amazon.ca, and I think I'm "somewhat" in luck. Amazon.ca has a Dorman ($192.90 CAD) and SMP ($219.46 CAD) vapor canister. Both have "free" shipping since I'm a Prime member BUT these will take longer to arrive than if I went with RockAuto (ie. July 21st)... but with RockAuto, the total cost including tax, shipping/handling, and duties would be $229.00... so I would save about $26.46 if I were to wait until July 24-25 for the Dorman vapor canister (whereas the SMP would be July 25 - Aug. 4, which is non-negotiable since I fly out July 31st).

UPDATE #2: I ended up pulling trigger on the Dorman vapor canister. It's the cheapest new canister I could find, which is better than getting a used one. To my surprise, when I placed the order, the estimated delivery date changed to July 22nd, so that's great news too. In terms of verifying the part number for my '02 Pathfinder, I first checked out Nissan Parts Royal Oak website https://www.nissanpartsroyaloak.ca/oem- ... c3VsdHM%3D, which says that Part # 14950-3H00B will fit the '02-'04 Pathfinder, then I went to another website that had the Dorman vapor canister, PartsAvatar.ca https://partsavatar.ca/dorman-oe-soluti ... er-911-529, which shows the Dorman part # to be "911-529" (and is OE Cross Referenced with the 14950-3H00B), and lastly, because I place little weight on Amazon's "part fitment", the Dorman part number is the same as the one shown on Amazon.ca's https://www.amazon.ca/Dorman-911-529-Ev ... Pathfinder. So I'm pretty confident this is the right part for my '02 Pathfinder, and just pulled the trigger on this.

[cmx378]

Or you could hang it with zips and tell your co-worker to replace the bracket at his leisure. It certainly won't affect the way it runs.

Unfortunately, my co-worker is not really "mechanically inclined" to DIY. She's a newer mom.

[VStar650CL]

It's plastic. You should plug your VIN in at NissanPartsDeal.com. Your Pathy should be a US/Canada model, so I think that will work. That will give you the Nissan part number, then you can plug that into the Part Number Search tab at RockAuto and be sure you're getting the right one.

[cmx378]

It's plastic. You should plug your VIN in at NissanPartsDeal.com. Your Pathy should be a US/Canada model, so I think that will work. That will give you the Nissan part number, then you can plug that into the Part Number Search tab at RockAuto and be sure you're getting the right one.

Unfortunately, it won't accept my VIN, it gave me the following message :

"Currently we are unable to process your VIN number.
Please use Select Vehicle by Model function to continue the shopping process."

Ah, ok, well if it's plastic then maybe I won't be able to heat the screws/bolts then...

[VStar650CL]

Call a Canadian Nissan dealer, then. They'll be able to pull up the correct part number from your VIN. You don't want to pay good money for guesswork that might end you up with holes in the wrong places.

[cmx378]

Call a Canadian Nissan dealer, then. They'll be able to pull up the correct part number from your VIN. You don't want to pay good money for guesswork that might end you up with holes in the wrong places.

Good idea. I called and confirmed with my VIN, that it is the correct part number (Part # 14950-3H00B) in my earlier UPDATED post above.

Thanks for all your help! Now it's just a waiting game. I have an appointment to bring my vehicle in this Wednesday for them to look at the condition of the bolts/screws for removal/replacement, and if I go ahead with it, they'll wave the 1/2 hr diagnostic fee charge. While I was on the phone with the Parts Department, I asked to confirm the 3 bolts/screws part #'s, which was 08120-6122F, and would be about $7.00 CAD for all three of them, but would need to be shipped (~2-3 days) from Vancouver, BC, since there are none available in Alberta. Lastly, the Dorman vapor canister should arrive by this Friday... will update you as this progresses.

[cmx378]

UPDATE: I swapped the EVAP canisters over the weekend (note: I didn't weigh them on a scale since I don't have one, but the old one did seem slightly heavier than the new Dorman one, after holding one in each hand). Haha, and like most, as careful as I was, I ended up breaking/snapping 1 of 3 mounting bolts/screws; luckily it was the "easier" (ie. to access/see) bolt/screw (the one closest to the front of the vehicle, or the one end of the EVAP canister with one mounting hole) that I snapped off.

After heating and bathing the broken bolt/screw with penetrating fluid, multiple times, and using a screw extractor with no success, I ended up drilling the bolt/screw out and then sanded/reamed the hole with a circular file to make it smooth, as I was just going to zip-tie it (or borrow/rent a tap & die set to re-thread the hole, but only if I had time). I was able to remove the other two bolts/screws by heating them and "working" them out, left and right, until they finally came out. I also didn't bother removing the bracket the EVAP canister is mounted to, as it didn't seem like I needed to and it was additional time/effort/cost that I didn't want to (or more so couldn't) incur since time is against me before I move to Europe in less than week....

However, the thing that has me a bit surprised/stumped are the replacement bolts/screws that Nissan is saying is a direct replacement . According to Nissan, the part # for the EVAP mounting bolts/screws is 08120-6122F and that's what it shows on the parts diagram below (from www.NissanPartsDeal.com): https://www.nissanpartsdeal.com/parts/n ... 5=XE;6=AT)

Side-by-side, this is the difference in length between what I removed from my Pathfinder (left) and what I'm being told is the replacement bolt/screw (right) :

Can anyone confirm if Nissan replaced the original EVAP mounting bolt/screw with a significantly shorter one (ie. 08120-6122F)? If so, can they also provide that original part # (if available)?

In any case, I ended up using the shorter bolts/screws anyways, but of course, they probably only thread into the bracket/nut about 1/4" (because that's roughly how much of the bolt/screw sticks out after going through the mounting hole of the EVAP canister. Oh, and I put anti-seize on the threads in case someone else ever needs to take these out (just giving them a better chance). I kind of wonder if Nissan replaced the longer bolts/screws with the shorter ones since they know they rust/seize in the mounting bracket/nut over time. In theory, the shorter bolt/screw should be easier to "extract" if it were to eventually rust/seize in there (because you're basically threading out half the length of a rust covered bolt/screw)

Lastly, after swapping the EVAP canister and putting all the hoses back on, I drove it around for a few hours yesterday while doing some errands, and so far no CEL. However, I'm not celebrating yet since it took some time before the CEL to come back on after I previously swapped the fuel filler neck, cleared the code, and drove it around for a few days. So I will continue driving it for the next couple of days and hope that the CEL doesn't come back on. I'll post another update in a few days.

Cheers.

[VStar650CL]

We techs universally cuss about how unnecessarily long those factory screws are. They're holding up a couple pounds of silly plastic, not an artillery piece. The short ones are a lot less prone to seizing even without anti-seize, so as far as I'm concerned, God bless the guy at DPIC who spec'd the shorter replacements!

[cmx378]

Haha, so true, the original factory bolts are unnecessarily long for these EVAP canisters, which was why I was fine with using the (new) shorter ones and calling it a day. As for another update, Day 2 of driving and no CEL, so hopefully we're on the right track with the EVAP canister being the culprit for my P1456 DTC. If it continues to stay off by this Friday, then I'll consider the issue "solved".