P0456 Evap System Small Leak

[Bryan Savage]

Wouldn't you know it, my Malfunction Indicator Lamp (MIL) turned itself on while I was at Watkins Glen last weekend. Awesomely, the Gen V cars will tell you their own codes, thusly:

You must be registered for see images attach

Back from my mechanic days at the Chrysler/Jeep dealership, this Diagnostic Trouble Code (DTC) was one of the most annoying. The likeliest culprit (read, the easiest possible repair) was the ol' gas cap leak. Well, with most new vehicles these days, and the Gen V Viper included, there ain't no gas cap.

You must be registered for see images attach

As I'm sure you all know, part of the federal emissions requirements in all new vehicles is the closed fuel system. Evaporating fuel vapours are bad for the environment and can also create nice explosive atmospheres if all the conditions are met.

Gasoline is very volatile, meaning under atmospheric pressure, it will vaporise fairly quickly. All the empty space in your fuel tank is going to fill with fuel vapours, and those vapours are not allowed to escape to the outside atmosphere. So the Evaporative Emissions System (EVAP) exists on your vehicles to keep all those vapours in check. There's a seal around the fuel filler to hold the pressure in, there are vent lines to and from the fuel tank to allow for the expansion and contraction of the fuel as temperature fluctuates, and there's a charcoal canister and a pump or two to force stray vapours into the engine intake for combustion, or to capture them in said charcoal canister if conditions are not right for combustion.

The system monitors the pressures, and if they are too low, you must have a leak. The MIL exists only for emissions reasons, and none of them are fatal to your engine, so the light is always orange. If you have any lights that are red, that is bad, and you should probably not be driving.

Most DTCs record the sensor readings in a shapshot of when the code was set, which sometimes helps you figure out their cause. The car monitors what's going on at all times, and if the conditions for tripping the code are not met, usually three "Global Good Trips", the MIL will turn off and not bother you anymore, even though the code will stay in the memory as a "non-active" malfunction.

I've seen loose gas caps, cracked seals on gas caps, spilt vacuum lines, relocated hoseclamps, bad pumps, and clogged canisters cause EVAP leaks, but read any story about this DTC and most of the time, the dealership will come back with "could not duplicate" or they will replace the easiest-to-replace part (since warranty work doesn't pay well for diagnosis) and send the customer on their way.

The closest SRT High Performance dealer to me is 79 miles away, and I'll be buggered if I'm going to drive all that way for a "we couldn't find anything so we cleared the code and see you later".

So I figured I'd run it by here. Has anyone else in a Gen V tripped this code? If you fixed it, what was the solution? I have done zilch as far as a visual inspection for anything. Sitting on my couch and asking the internet is easier than moving.

Two possible causes I've come up with, besides component failure:

1) When fuelling up the car, I put the nozzle into the filler and let it hang there on it's own, so I can pick my nose or Tweet things while I wait. Perhaps the weight of the filler nozzle has bent part of the car's filler sealing mechanism, not allowing it to self seal any longer.

2) The code tripped after the car sat in the hot sun all day long at Watkins Glen. Perhaps the elevated temperatures cause high vapour pressure in the system, and it found a way to sneak past a weak hose clamp and hose barb somewhere in the system, and now cooler temperatures aren't contracting the hose enough to seal the leak again.

Thoughts, anyone?

 

[Steve-Indy]

Nice write up.

I'd clear the code and watch. Within our immediate group, there are only 4-5 Gen V's...but, so far, I have not seen this code.

 

[Bobpantax]

When I first got the car, it through this code. Since there was no apparent reason for it - no smell, etc., I had the dealer check the calibration. It turned out that there had been an update. I had the update done while I waited. Has not happened since. Have the dealer check yours first to see if that is the issue. If not, you will have to leave it and have them run a leak test.

Or, as posted above, since you live so far from the dealer, if you do not smell anything inside or outside, fill the tank up, and after three cycles, the code may clear itself.

 

[Bryan Savage]

Nice write up.

I'd clear the code and watch. Within our immediate group, there are only 4-5 Gen V's...but, so far, I have not seen this code.

Thanks Steve!

When I first got the car, it through this code. Since there was no apparent reason for it - no smell, etc., I had the dealer check the calibration. It turned out that there had been an update. I had the update done while I waited. Has not happened since. Have the dealer check yours first to see if that is the issue. If not, you will have to leave it and have them run a leak test.

Or, as posted above, since you live so far from the dealer, if you do not smell anything inside or outside, fill the tank up, and after three cycles, the code may clear itself.

Yeah, I don't see an option to clear the code from the instrument panel. It may require disconnecting the battery, and I don't want to do that. I have a Diablosport Predator for my old 300 that I might be able to use to clear the code, but I'm too lazy. I'll just drive the car more and see if it goes away. That seems like the easiest thing to do.

 

[Bobpantax]

I was told to not use the battery disconnect method. If you fill it up and there is no actual problem, after three start up cycles it should clear. It tests itself once a day at the first start up. My guess would be that since it happened at a track day that the combination of heat and sloshing around triggered the code. The system is hyper sensitive. But, when you get a chance, you should see if your programming needs updating. If you call or email your dealer with your VIN number, they should be able to tell you whether it needs updating.

 

[viperbilliam]

Thanks for the educational post. Nice to see a brief explanation of the code in the info center instead of just a code that has to be looked up.

 

[Hoosier Daddy]

Same problem with my sons 2008 mercedes C class. Smoke tested the eval system and low and behold a smoke coming from around the top of the gas tank. No fume smell or anything. Dealer say 4K to drop rear axel, drop tank and replace seal or solenoid. Wonderful

 

[zim32]

Wouldn't you know it, my Malfunction Indicator Lamp (MIL) turned itself on while I was at Watkins Glen last weekend. Awesomely, the Gen V cars will tell you their own codes, thusly:

You must be registered for see images attach

Back from my mechanic days at the Chrysler/Jeep dealership, this Diagnostic Trouble Code (DTC) was one of the most annoying. The likeliest culprit (read, the easiest possible repair) was the ol' gas cap leak. Well, with most new vehicles these days, and the Gen V Viper included, there ain't no gas cap.

You must be registered for see images attach

As I'm sure you all know, part of the federal emissions requirements in all new vehicles is the closed fuel system. Evaporating fuel vapours are bad for the environment and can also create nice explosive atmospheres if all the conditions are met.

Gasoline is very volatile, meaning under atmospheric pressure, it will vaporise fairly quickly. All the empty space in your fuel tank is going to fill with fuel vapours, and those vapours are not allowed to escape to the outside atmosphere. So the Evaporative Emissions System (EVAP) exists on your vehicles to keep all those vapours in check. There's a seal around the fuel filler to hold the pressure in, there are vent lines to and from the fuel tank to allow for the expansion and contraction of the fuel as temperature fluctuates, and there's a charcoal canister and a pump or two to force stray vapours into the engine intake for combustion, or to capture them in said charcoal canister if conditions are not right for combustion.

The system monitors the pressures, and if they are too low, you must have a leak. The MIL exists only for emissions reasons, and none of them are fatal to your engine, so the light is always orange. If you have any lights that are red, that is bad, and you should probably not be driving.

Most DTCs record the sensor readings in a shapshot of when the code was set, which sometimes helps you figure out their cause. The car monitors what's going on at all times, and if the conditions for tripping the code are not met, usually three "Global Good Trips", the MIL will turn off and not bother you anymore, even though the code will stay in the memory as a "non-active" malfunction.

I've seen loose gas caps, cracked seals on gas caps, spilt vacuum lines, relocated hoseclamps, bad pumps, and clogged canisters cause EVAP leaks, but read any story about this DTC and most of the time, the dealership will come back with "could not duplicate" or they will replace the easiest-to-replace part (since warranty work doesn't pay well for diagnosis) and send the customer on their way.

The closest SRT High Performance dealer to me is 79 miles away, and I'll be buggered if I'm going to drive all that way for a "we couldn't find anything so we cleared the code and see you later".

So I figured I'd run it by here. Has anyone else in a Gen V tripped this code? If you fixed it, what was the solution? I have done zilch as far as a visual inspection for anything. Sitting on my couch and asking the internet is easier than moving.

Two possible causes I've come up with, besides component failure:

1) When fuelling up the car, I put the nozzle into the filler and let it hang there on it's own, so I can pick my nose or Tweet things while I wait. Perhaps the weight of the filler nozzle has bent part of the car's filler sealing mechanism, not allowing it to self seal any longer.

2) The code tripped after the car sat in the hot sun all day long at Watkins Glen. Perhaps the elevated temperatures cause high vapour pressure in the system, and it found a way to sneak past a weak hose clamp and hose barb somewhere in the system, and now cooler temperatures aren't contracting the hose enough to seal the leak again.

Thoughts, anyone?

Had the MIL light go on at about 2500 miles when starting cold one morning after returning the from a track day the day before. Took it to the dealer...he said it it was a "evap leak"...cleared the code...said drive it...if it comes back the will do a further check. Didn't know we could access the fault code ourselves.

Did that code come up on the dash..or did you have to use the menu to find it?

 

[Bryan Savage]

I was told to not use the battery disconnect method. If you fill it up and there is no actual problem, after three start up cycles it should clear. It tests itself once a day at the first start up. My guess would be that since it happened at a track day that the combination of heat and sloshing around triggered the code. The system is hyper sensitive. But, when you get a chance, you should see if your programming needs updating. If you call or email your dealer with your VIN number, they should be able to tell you whether it needs updating.

Thanks, Bob. Back in the day, the car would test itself at each start-up. I drove it again the other day and there's no change to the code. I hit up the Vehicle Assistance mode from in the car, but they really can only help with UConnect stuff. They couldn't tell me what my PCM part number was. I also called Midway Chrysler in San Diego (since they are still open at this writing) and gave them my VIN, but they were unable to help.

Thanks for the educational post. Nice to see a brief explanation of the code in the info center instead of just a code that has to be looked up.

Yeah! That's the first time I've ever seen a vehicle display its own codes. Talk about handy!!

Same problem with my sons 2008 mercedes C class. Smoke tested the eval system and low and behold a smoke coming from around the top of the gas tank. No fume smell or anything. Dealer say 4K to drop rear axel, drop tank and replace seal or solenoid. Wonderful

For those who don't know, the "smoke test" is where you disconnect one of the EVAP lines, and hook in a machine that pressures the system up with white smoke. It's just a visual aid in finding a leak.

Had the MIL light go on at about 2500 miles when starting cold one morning after returning the from a track day the day before. Took it to the dealer...he said it it was a "evap leak"...cleared the code...said drive it...if it comes back the will do a further check. Didn't know we could access the fault code ourselves.

Did that code come up on the dash..or did you have to use the menu to find it?

If you use the "up" and "down" arrows on the steering wheel, scroll to the icon of the stethoscope.

You must be registered for see images attach

You'll then get a prompt to hit the "right" arrow to display the codes.

You must be registered for see images attach

You don't have the option of clearing them or seeing the snapshot data, but you can at least look at what code is present.

 

[Bobpantax]

You do not need the PCM part number. A Dealer that has a Viper tech or at least someone Viper savy, ( not all do) can check your PCM status with your VIN since its current status will show in the system. The dealership you called was either ignorant or lazy.

 

[Bryan Savage]

You do not need the PCM part number. A Dealer that has a Viper tech or at least someone Viper savy, ( not all do) can check your PCM status with your VIN since its current status will show in the system. The dealership you called was either ignorant or lazy.

Possibly a bit of both. It sounded like they were busy. I'm sure that they wouldn't get too many inquiries like that from Viper people. I certainly wouldn't expect them to drop everything and ask everyone. It's kind of an oddball question, I think.

For them to be able to tell what flash update my PCM has, they would either have to be monitoring the car remotely, or it would have to be on record that I had visited a dealership and had received an update. If they actually keep track of that data, things sure have come a long way since I was a mechanic!

It's not like I'm in a big rush, and I'm certainly not upset that my new flagship has a MIL illuminated. It's part of the process. Maybe I'll learn something along the way. Thanks for the attention!

 

[Jack B]

The dealers that sell the viper were required to purchase a scan tool that connects to the car and also is on-line with the factory. That is how the firmware is checked for the latest version. I do not think a typical Dodge dealer can check the viper pcm. Some of the dealers had the scan tool prior to the G5 introduction, however, it will not read the G5 pcm unless you upgraded the firmware and that upgrade is not available to non-viper dealerships. If something has changed let us know.

Possibly a bit of both. It sounded like they were busy. I'm sure that they wouldn't get too many inquiries like that from Viper people. I certainly wouldn't expect them to drop everything and ask everyone. It's kind of an oddball question, I think.

For them to be able to tell what flash update my PCM has, they would either have to be monitoring the car remotely, or it would have to be on record that I had visited a dealership and had received an update. If they actually keep track of that data, things sure have come a long way since I was a mechanic!

It's not like I'm in a big rush, and I'm certainly not upset that my new flagship has a MIL illuminated. It's part of the process. Maybe I'll learn something along the way. Thanks for the attention!

 

[Bobpantax]

As Jack said above, only a qualified Viper dealer could do this. Since the programming of the Gen V is complex, any update would be done by a dealer and would be logged into the system that preserves the service data on the car. That system is nationwide. So if you give a Viper dealer your VIN, it should be able to tell what the car was loaded with at the factory; whether it was updated later by the dealer you bought it from; and whether there is an update available now. Of course if you need an update, you will have to bring it in to the dealer. It really is not an odd ball question. It is a legitimate question and you are entitled to an answer.

Possibly a bit of both. It sounded like they were busy. I'm sure that they wouldn't get too many inquiries like that from Viper people. I certainly wouldn't expect them to drop everything and ask everyone. It's kind of an oddball question, I think.

For them to be able to tell what flash update my PCM has, they would either have to be monitoring the car remotely, or it would have to be on record that I had visited a dealership and had received an update. If they actually keep track of that data, things sure have come a long way since I was a mechanic!

It's not like I'm in a big rush, and I'm certainly not upset that my new flagship has a MIL illuminated. It's part of the process. Maybe I'll learn something along the way. Thanks for the attention!

 

[VENOM V]

Bryan,

I'm curious if your code either self-cleared or you took it to the dealer.

My car just threw the same code this morning when I started it. I recently took it to the dealer for service and they updated the software, so I don't think that's the issue.

Thanks

Todd

 

[mblgjr]

Well... 3700 miles and mine threw the code as well.

Car had been sitting for about 10 days; though I had been in/out of the car with the keys a few times while cleaning it. But had not been started.

Fired it up and about 5 seconds later it throws the code for a "medium" leak. Never smelled anything in the garage. Average temp inside around 75* with no fuel agitation since it had been sitting.

Filled up before coming home, so maybe it can make up its mind and act right.

On another note, has anyone had issues with fuel blow-back when filling up? I always hold the pump nozzle and have never let it rest down when filling. ALWAYS stop fueling when it kicks off and wait 3-5 seconds before withdrawing. However, on 2 occasions at 2 diff stations I've had fuel backwash/blowback out of the filler neck. Highly pissed both times. Now I just wait much longer before moving the nozzle after it shuts off.

 

[Bryan Savage]

Bryan,

I'm curious if your code either self-cleared or you took it to the dealer.

My car just threw the same code this morning when I started it. I recently took it to the dealer for service and they updated the software, so I don't think that's the issue.

Thanks

Todd

Hey Todd,

The same code is still present. I've driven the car another thousand miles since it first came on, and there's been plenty of opportunities for it to clear, and it hasn't. Which tells me there's a mechanical problem I need to look into. From the sound of your post and mblgjr's below, maybe there's a common issue we all share. Perhaps there will be a TSB issued if there's a problem found.

Well... 3700 miles and mine threw the code as well.

Car had been sitting for about 10 days; though I had been in/out of the car with the keys a few times while cleaning it. But had not been started.

Fired it up and about 5 seconds later it throws the code for a "medium" leak. Never smelled anything in the garage. Average temp inside around 75* with no fuel agitation since it had been sitting.

Filled up before coming home, so maybe it can make up its mind and act right.

On another note, has anyone had issues with fuel blow-back when filling up? I always hold the pump nozzle and have never let it rest down when filling. ALWAYS stop fueling when it kicks off and wait 3-5 seconds before withdrawing. However, on 2 occasions at 2 diff stations I've had fuel backwash/blowback out of the filler neck. Highly pissed both times. Now I just wait much longer before moving the nozzle after it shuts off.

Oooo a medium leak? That ought to be easier to find than a small leak. IIRC, there's a "large" leak code available too.

The SRT folks did a quick check for me to see if there was any button sequence available to display the current ECU flash number, but there is not.

The light is annoying to me, but not enough that I've done any further investigation.

As for the fuel filling thing... I've run into a few pumps that don't enjoy the Viper's filler mechanism. The auto-stop keeps auto-stopping, so I have to rotate the pump handle upside-down to get it to insert far enough to compress the spring in the handle. I stop filling when the auto-stop stops, and the one time I gave it an extra squirt, the car spit it back at me when I removed the pump. LOL.

Now once it stops, I'll slowly pull the handle out to let those last few dribbles get out of the pump. As soon as the nozzle comes out, the door will snap shut and there doesn't seem to be a drain, so get the handle away from the car as soon as you can to avoid dripping on the car.


If either of you is less lazy than me and does some actual investigating into the MIL, let us know what you come up with!

 

[VENOM V]

Well good news so far. I took it to the dealer, he cleared the code within 5 minutes of my arrival and it hasn't recurred since. I'll let you guys know if it happens again.

 

[Bryan Savage]

Well good news so far. I took it to the dealer, he cleared the code within 5 minutes of my arrival and it hasn't recurred since. I'll let you guys know if it happens again.

Thanks for the update!

 

[TrackAire]

Well... 3700 miles and mine threw the code as well.

Car had been sitting for about 10 days; though I had been in/out of the car with the keys a few times while cleaning it. But had not been started.

Fired it up and about 5 seconds later it throws the code for a "medium" leak. Never smelled anything in the garage. Average temp inside around 75* with no fuel agitation since it had been sitting.

Filled up before coming home, so maybe it can make up its mind and act right.

On another note, has anyone had issues with fuel blow-back when filling up? I always hold the pump nozzle and have never let it rest down when filling. ALWAYS stop fueling when it kicks off and wait 3-5 seconds before withdrawing. However, on 2 occasions at 2 diff stations I've had fuel backwash/blowback out of the filler neck. Highly pissed both times. Now I just wait much longer before moving the nozzle after it shuts off.

When I visited CAAP during the Homecoming event, I was surprised to see how the fuel filler system works on the Gen 5. The fuel filler hose entering the tank is literally only 1" in diameter. Also, the hose enters the tank at the bottom half, about 1" below the belt line. I would assume any issues with venting of the tank will cause either the pump to click off or a back splash of fuel.

I am also going to assume the Gen 4 is the same since I've had similar filling issues at certain stations.

 

[mblgjr]

The blowback doesn't happen all the time. And happened in completely different ambient conditions (different regions of the US even). Just annoying since I waited quite a bit before removing. It happens after pump has stopped completely.

As to the EVAP code; I'd like to know if yours repeats. I plan to clear mine as well because I doubt there is "really" an issue. I've done a visual inspection and sniffed around to no avail.

The Jeep Grand Cherokee guys are having similar EVAP code issues (completely different system) but still...

 

[Lawrenzo]

I took my 2013 to the dealer today for the EVAP issue code #P0456- they showed no faults. There is a TSB#18-044-14 for this issue which requires a PCM reflash though.

 

[Bryan Savage]

I took my 2013 to the dealer today for the EVAP issue code #P0456- they showed no faults. There is a TSB#18-044-14 for this issue which requires a PCM reflash though.

Good to know! I did a quick search on the TSB number and came up with El Zilcho. I'm at 3,100 miles now and my light is still on. I think a Saturday road trip to the closest dealer might be a fun activity after all.

 

[mblgjr]

Im subscribed to a tsb service and dont show any for evap. And cant find anything regarding the # posted above either.

I will prob just clear the code on mine and see if it resets again. Anything to stay away from the dealer.

 

[mblgjr]

Any updates for a resolution?

 

[Jack B]

I am pretty sure that one of the factory update flashes had verbiage indicting that part of the flash included a adjustment to the Evap System. Have your dealer read the details of the latest flash.

Any updates for a resolution?

 

[mblgjr]

Thanks a lot. Will look into it.

 

[Bryan Savage]

Well, here's an update.

Like with most problems in life, I try to solve them by doing nothing.

At 6,800-ish miles, while on the highway, the light turned off. I did nothing at all.

Oh, and the battery-disconnect thing doesn't do anything at all. I took the negative cable off for half an hour, and the car remembered everything.

*shrug*

 

[ViperJeff]

Very interesting........

Hate not knowing something is fixed for good.