don't take this the wrong way but...NEVER EVER FILL UP YOUR TANK WITH THE CAR RUNNING. It's for your and your car's own good.

The code if you look it up in google says that it's an "evaporative emissions system small leak detected." For more info: https://mbworld.org/forums/c-class-w...evap-leak.html

hope this helps!

 

Thanks for the reply

Not taking anything the wrong way...question is...can I fix this without spending $$$$ unnecessarily? I need to take a 5 hour road trip Friday afternoon (family emergency). Like I said, my car doesn't have any weird sounds and seems to be running like it was the day I bought it (13 months ago). If I drive it am I risking major damage???

So...Lesson learned. I will NEVER EVER EVER EVER EEEEVVVVVVER leave her running while I'm fueling up! Promise!!

K...so now what?

^..^

 

P0456: Purge System, Very slight leak in system

Usually if the gas cap is loose or isn't on you don't get a P0456 (very slight leak). Instead you get a P0455 which is (major leak).

Your problem is the Purge Control Valve or the Fuel Tank Pressure Sensor.

Purge Control Valve




Fuel Tank Pressure Sensor

 

SWEET!!! Thank you SO much!! To run the diagnostic testing I was quoted $125/hr - $189. The Service Adviser at the Benz dealership did say the Purge Valve is known for going bad. He also said that the CEL would go off in 3 days or so if it was something simple like fueling while car was running. I'd think it's safe to say it's the purge valve or the other thing.

I listened to my car today...still not hearing anything unusual. Should I be?

Is it something I can repair myself?

Thanks again! I really appreciate cha!!

 

You can change the purge valve yourself. Hang on a sec let me get you more info and directions. The purge valve seems something similar to this so swapping it out should be a breeze.

 

THANK YOU!!! I would really like to make sure I am good to go before I take off on a 5 hour road trip tomorrow.

^..^

 

you should be fine for your road trip, but definitely replace it yourself 'cause it will save you a lot of money! this forum is a great resource to learn how to do a lot of this stuff yourself, welcome aboard!

you should post up some pics of your car soon!

 

Thanks!!! I will post pics of my baby soon! The advice and help are really appreciated!!!!!

 

Hello, I came across to this thread coz I am having the same problem.... can you share info on how to replace purge valve? thanks much

 

How do you know the purge valve needs replacing? Are you getting the P0456 code on your OBDII tool? I was getting that code and replaced the purge valve and that was not the problem on my 2005 C230 Kompressor. I had a different problem and a very less costly solution than what the dealer suggested less costly. Let me know thanks Doug and I'll try to help.
Doug

 

Yeah, Im getting an on and off CEL and was getting P0456 code. Thanks.

 

I assume you are resetting the CEL. Without correcting the problem it will keep popping.
Anyway, I was getting that code. This is what I did.
1. I took the soft rubber seal off the inside of the gas cap in case the leak was thru the cap. Cost nothing but didn't solve the problem and I kept getting the P0456 code. I went to my independent mechanic who ran a smoke test to find the leak but he was unable to find it and suggested I go to the MB Dealer. Leaks can be difficult to find.
2. Took the car to the MB Dealer and was told I needed a new purge valve at a cost of about $450.00 installed. They did the work and 2 days later the same code popped.
Went back to the dealer who offered to replace the old purge valve but wanted me to pay the labor. I asked them what could cause this code to keep popping and they said there is a plastic tube running from the gas filler neck to a charcoal filter. Why they didn't look there the first time, I don't know, but they do like to sell new parts. They took the right rear fender liner off and discovered the plastic line was severed. They said it's possible snow built up (I'm in Canada) and a large bump could cause the wheel to smack the line and break it. They quoted me $671.00 to replace the part. I asked them to put the car back together and left. Of course I was out the $450 but I do have a new purge valve lol.
3. I went to my independent mechanic and we found the leak. He put a stent on the broken line and charged me $90.00. That was over 2 years ago and problem solved.
So that's what happened to me. I would try the simple fixes before investing in a bunch of expensive parts. Needless to say, if you can find an independent mechanic that you trust...that's the best way to go. The Dealers expect that cost is never a problem. This forum has a lot of great info, and lots of folks happy to help.
Good luck with this.

 

I appreciate your help! I'll go and do that. Ill go by my local mech that does my tune ups for me. *crossing my fingers* hopefully id have as simple issue as you.

 

Good luck, I hope this works out OK for you...

 

Old thread, but a quick question. The pic of the fuel pressure sensor on top of the gas tank, has the floorboard been removed to gain access? If so, is there a tutorial? I'm getting the P0456. Trying to find the easiest access to that sensor if I need to change it out.

 

It's a small plate with about 6 screws if I'm not mistaken. Pop that off and you will have access inside the tank. It is sitting under the rear driver side seats. Very easy to get to.

 

After posting, I hit YouTube and found a couple of videos. Doesn't look hard at all. Gonna change out the purge valve first and see if that clears the code. Thanks for responding.

 

 

Purge valve has been replaced. Reset CEL. So far, so good. It's my wife's car and it hardly gets driven. It's a 2006 C230 and only has 71,565 miles. It is shocking how things still break down with mileage that low.

 

When I got the P0456 it was the fuel filler neck that was leaking. Pricey part. If your P0456 comes on when your fuel tank is at half or less, then it's most likely the filler neck. Alternatively, clear the code and keep your fuel tank above half full and the code will not pop up...the test that triggers p0456 only occurs when the tank is at or below half full.

 

Thanks! I'll keep that in mind.

 

There is a YouTube video I found where a 2005 MB owner removed his filler neck assembly, smoke tested it, and found a hairline crack in a plastic barb located near the actual fuel filler opening. As another user above had his mechanic perform, he was able to repair it by creating a “stent” type repair. I don’t know if it was the same spot.

Because I don’t own a smoke tester and really didn’t wanna take out and possibly replace the entire assembly, I started thinking of other ways to attempt a repair under the assumption my leak causing the same code was in the same location as the YouTuber’s. What I discovered was that you can access the spot by simply pressing down the rubber shroud/gasket where the fuel opening is. You can see the spot where the hose connects to the barb. I purchased a product called Permatex spray seal and sprayed several coats on there. So far, the P0456 code has not returned. Something for others to think about and possibly try.

Here is a link to the YouTube video. Many props to this guy!


Here are pics I took of the repair spot from the fuel opening.

 

Old thread, I know, but our cars are getting old too...
My patient is a 2016 gl450 but evap systems are similar on many cars. This is the only decent thread I could find for Mercedes so I hope this helps someone avoid replacing too many parts in an attempt to find the source.
Following some of the advice here I began googling and digging around the car. P0456 small leak evap system code is what I had. I was able to locate and diagnose a faulty purge valve using a 10$ handheld vacuum pump from aliexpress and my voltmeter with a couple leads of wire. This page gave step by step instructions and mine failed the suction test:
https://www.samarins.com/glossary/purge-valve.html.
I found the valve at an online parts dealer for 51$ and installed it in 10 minutes. On the gl450 it sits right above the coolant expansion tank on the drivers side of the engine. Cleared the code and so far it hasn't come back. Used to come on right away after engine start.
Next step would have been a smoke tester which are about 50-60$ on Amazon. The maker, autoline, has helpful videos on their site to do a successful smoke test. You need one with a low pressure mode for the evap system or you can cause damage to the fittings and seals and make the job even more expensive.
Thanks to all who contributed some advice here. It got me started on the road to solving this issue.

 

I like Scotty Kilmers smoke tester. A Cigar and you LOL.
Well the only time I thought I needed it, I didn't because after looking around I found
3 hoses that needed replacement.
Jump to 1:07
Glad to hear you got your GL sorted out.