OBDII Code - P0456

[z1ggy]

Any of you guys experience this code in your car? If so, what was the fix? I'm fairly handy and looking to try and fix this myself before bringing to a shop. It needs to get resolved fairly soon as my car registration is up in November and at that time emissions are done.

For reference, code means "Evaporative Emissions System Small Leak Detected".

 

[PClark99]

Off the top of my head. Could be gas cap is loose or a bad gasket. That’s probably the easiest thing to check.

 

[boomerang]

Let me guess, 2012 Rollscanhardly with the 6.7L V12 Diesel? /s

 

[z1ggy]

Off the top of my head. Could be gas cap is loose or a bad gasket. That’s probably the easiest thing to check.

I checked the gas cap... seems to form a tight seal, although I'm not an expert ... I don't really see a gasket there? Which gasket are you referring to?

Let me guess, 2012 Rollscanhardly with the 6.7L V12 Diesel? /s

2011 mazda 3, 120k miles

 

[dave_the_nerd]

I checked the gas cap... seems to form a tight seal, although I'm not an expert ... I don't really see a gasket there? Which gasket are you referring to?

There should be a gasket (or o-ring) in the cap itself. There are also gaskets, valves, vents, and hoses elsewhere in the EVAP system - exact location varies depending on the car. When they degrade or break, it'll cause a small leak. But a loose or damaged gas cap is usually - usually - the culprit for that code, regardless of the type of car.

I'd gamble and just replace the gas cap first, and if that doesn't help, take it to a mechanic where they can do proper leak detection. (Unless you have a smoke machine and some experience in this area... it's not something I'd trust myself to do.)

 

[chubbyfatazn]

I got this code back in June right before I took my '03 4Runner in for inspection. Teh interwebs said the P0456 code was most commonly due to the gas cap (faulty seal), so I ordered a new OEM cap and the code went away. Apparently I could've just replaced the o-ring on the cap (the gasket) and been done with it, but for $17 for a new cap I was too lazy to even consider it.

On a slightly related note, more of an fyi - the EPA mandates all vehicles sold in the US, regardless of make and model, to have an 8 year/80k mile warranty on "major emission control components".

https://www.epa.gov/transportation-...frequent-questions-related-transportation-air

 

[z1ggy]

There should be a gasket (or o-ring) in the cap itself. There are also gaskets, valves, vents, and hoses elsewhere in the EVAP system - exact location varies depending on the car. When they degrade or break, it'll cause a small leak. But a loose or damaged gas cap is usually - usually - the culprit for that code, regardless of the type of car.

I'd gamble and just replace the gas cap first, and if that doesn't help, take it to a mechanic where they can do proper leak detection. (Unless you have a smoke machine and some experience in this area... it's not something I'd trust myself to do.)

Thanks Dave. I will buy a replacement cap as I have 0% experience in that area. I just do small repairs/planned maintenance jobs.

I got this code back in June right before I took my '03 4Runner in for inspection. Teh interwebs said the P0456 code was most commonly due to the gas cap (faulty seal), so I ordered a new OEM cap and the code went away. Apparently I could've just replaced the o-ring on the cap (the gasket) and been done with it, but for $17 for a new cap I was too lazy to even consider it.

On a slightly related note, more of an fyi - the EPA mandates all vehicles sold in the US, regardless of make and model, to have an 8 year/80k mile warranty on "major emission control components".

https://www.epa.gov/transportation-...frequent-questions-related-transportation-air

Interesting point, did not know that. 120k on the car though, so it no longer applies.

 

[dave_the_nerd]

Thanks Dave. I will buy a replacement cap as I have 0% experience in that area. I just do small repairs/planned maintenance jobs.

Just a thought - maybe somebody will let you borrow a cap to test? (They're not super-expensive, but it can't hurt to ask either.)

 

[boomerang]

I thought I'd read that some of the auto parts stores (probably the chains) can test the cap.

Did somebody else put gas in the car last? The cap needs to click at least twice when reinserted to properly seal.

 

[z1ggy]

Here in the great state of NJ, we higher class folks don't need to pump our gas (sarcasm aside... it's technically illegal to do so). I did however, take the cap off completely, check inside... put back on and tightened, 2 clicks. Still get the light. New Cap is on the way.

 

[Topweasel]

Just to note the few times that I have dealt with this error or something close. Just un screwing and screwing on the gas cap corrected it but not right away. Probably took another 30 min of driving to clear.

 

[z1ggy]

Replaced the cap, then cleared the code. Came back. Ffffffffack.

How much should I be expecting to spend to have the smoke test/eval done by a mechanic?

 

[96Firebird]

I've had a similar code (P0442 - Small evap leak) on my Park Ave since I bought the car 4 or so years ago. I'm pretty sure my problem is the lip on the gas filler tube is rusted so that seal is no longer good. You can check that.

I just keep clearing mine, it usually comes back after a month or so. I can usually get it off with enough time before my inspection to pass, so as long as that keeps happening it will stay as it is.

 

[dave_the_nerd]

Replaced the cap, then cleared the code. Came back. Ffffffffack.

How much should I be expecting to spend to have the smoke test/eval done by a mechanic?

Probably one hour or less of whatever the shops hourly labor rate is. Usually thats posted.

 

[BarkingGhostar]

I forget what it was called on my 2001 Tundra, but it was the crankcase evap valve. $79 from the dealership, or about $46 from 3rd party store. I let the dealership do it and replace all of the fitted hoses as they were getting pretty dry-rot. Had I not been in such a hurry I could have bought a complete kit through an out-of-town dealership parts department for half the price--and that through Amazon.

 

[snoopy7548]

I had issues with P0442 about seven or eight years ago (when my car was only a few years old). Dumped a lot of money into testing and repairs until they finally figured out it was the PCV valve.

 

[bradly1101]

The gas fume evaporative system can be damaged with overfilling the gas tank (not that you do that).

 

[z1ggy]

I've had a similar code (P0442 - Small evap leak) on my Park Ave since I bought the car 4 or so years ago. I'm pretty sure my problem is the lip on the gas filler tube is rusted so that seal is no longer good. You can check that.

I just keep clearing mine, it usually comes back after a month or so. I can usually get it off with enough time before my inspection to pass, so as long as that keeps happening it will stay as it is.

Yeah I think for now I might as well just clear it again, then bring it for emissions. I've been told they'll pass you as the sensor status would show up as "waiting", and not tripped, etc. However, at some point once I do try to sell this car for whatever it's worth, if I'm selling it as a whole car, then I'll need to get the code off. Depending when that is.... who knows, the thing might not even run any more and I could be selling it as parts or just donating it to the junkyard.

The gas fume evaporative system can be damaged with overfilling the gas tank (not that you do that).

Here in the great (fist pumping) state of NJ, we are legally not allowed to pump it ourselves. 99% of gas stations have attendants than come out and do it for you. It could very well be that these guysare over filling... Not sure.

 

[Polar2002]

I had the same error. I did the leak test $50. They found the small 90 degrees rubber hose near the tank had a split in it.

 

[SKORPI0]

Off the top of my head. Could be gas cap is loose or a bad gasket. That’s probably the easiest thing to check.

https://www.yourmechanic.com/articl...ons-system-small-leak-detected-by-jay-safford

 

[bradly1101]

Yeah I think for now I might as well just clear it again, then bring it for emissions. I've been told they'll pass you as the sensor status would show up as "waiting", and not tripped, etc. However, at some point once I do try to sell this car for whatever it's worth, if I'm selling it as a whole car, then I'll need to get the code off. Depending when that is.... who knows, the thing might not even run any more and I could be selling it as parts or just donating it to the junkyard.


Here in the great (fist pumping) state of NJ, we are legally not allowed to pump it ourselves. 99% of gas stations have attendants than come out and do it for you. It could very well be that these guysare over filling... Not sure.

Tell them to pull on first release!

 

[z1ggy]

Every man knows you gotta pull on first release!!!

Although guess my dad didn't....