Nygee

Anyone have experience with these codes . Minor and very evap emissions leak. 2013 g63. Truck runs fine no issues. Benz dealer has changed cap, purge, charcoal, filler neck and keeps coming back on. Now they're saying it's a sensor at the fuel tank and may need to change the fuel tank 5k. Ready to find an independent expert in NY.

SSleeper

What did you end up doing here? Our '17 G63 is throwing the same codes & replacing the fuel cap only helped for a few thousand miles.

CT189

I too was struggling to fix the same problem on a 13' G63 and finally was able to fix it. I suggest checking the fuel filter that is on the top of the fuel tank. Remove the 3 or 4 lugs that are held with Torx bolts and lift off the carpeting from the rear edge side where it tucks under the chrome strip. Then remove the 5"x5" inspection cover and you will be able to see the top of the fuel filter. If it is showing a accumulation of moist dirt on top or smell gas then the fuel filter has developed a crack in the plastic. The tank will have to be removed to replace the fuel filter. I did a smoke test on this car prior to discovering the bad fuel filter and no smoke was seen leaking from the fuel filter. After cleaning and removing the dirt from the fuel filter I could clearly see a crack near the tank pressure sensor.
After replacing the fuel filter the evap tests in mode 6 for the gross, medium, and small passed with no problems. I had replaced the purge valve, cannister, and the gas cap before this with no results. The cannister shut off valve is also part of the cannister and is not sold separately from MB. The code first appeared when the car was like 9.5 years old and 82000 miles. There also is a MB service bulletin which recommends that you install the latest software in the ME control unit for P0442 which I had done. Strangely enough the bulletin attributes the cause of the problem to poor quality gas!!! I suppose that if one didn't want to go through the trouble of dropping the tank then you could enlarge the inspection opening in the floor by cutting it and putting a appropriate sized sheet metal to cover it once finished. Dropping the tank was a bear on this so it might be a good option.

Nygee

I checked mine and even replaced the sensor although there was no smell. Smoke tests still turn up nothing .

CT189

The sensor is not the problem. It's the fuel filter that it mounts onto that is the problem. If there was no hint of dampness on the top of the filter then your's is ok.

Nygee

Shouldnt there be a smell? Or maybe it's so minor that's why no smell. Truck runs fine so haven't addressed it much especially since like you said the tank removal is long task

Thanks for your input

CT189

You may not be able to detect any smell because it could be a very small amount and may have evaporated. If you can take a air blow gun and blow off all the dust then it is ok. If any dust remains stuck and shows ANY sign of caking then it is probably leaking.
How many miles are on your car?

Nygee

Car has 56k miles.

CT189

I had another customer with the same problem at about that mileage but he traded the car in. I bet that your car also has a crack in the fuel filter.

Nygee

Thanks for the info. Guess I need to find a knowledgeable Indy shop in NY to tackle the fuel tank removal

CT189

This is the crack where my finger is pointing. Note the dark colored accumulation of dirt on the filter. Note that also the plastic has turned from white to a tan color due to the gasoline leak. If I had to do it again on a different car I would probably cut a bigger opening in the cargo compartment floor.

Crack on top of filter G63 2014

Nygee

I'm going to check mine again. If I recall it was clean. So u made a pass thru hole to avoid removing the tank ? How did u assemble it back.

CT189

I removed the tank and let me tell you it was a total pain. If you decide to enlarge the opening you can probably take a die grinder and cut it. You then would need to get a sheet metal to cover the now enlarged opening along with drilling 4 new holes to attach the new cover. It's like a 6.5 hour job in the labor guide so it will cost a bundle if you pay someone to do it.

Nygee

Ugggh. Thanks for all the advice

CaptnCharisma

This was a huge help! I've been chasing these codes for weeks. Changed out the purge valve, shutoff valve, whole charcoal canister, and fuel pressure sensor with no luck. As soon as I saw your photo I went down and pulled the access cover off and cleaned off the top of the tank and there it was. Just filled the gap with some sealant and hopefully this does the trick.

Nygee

Keep me posted on that. FYI it sounds like we have same issue and u changed almost everything I did except one supposedly common culprit the fuel filler neck. That didn't helpe but if yours still comes on maybe try that ?

CaptnCharisma

So far no codes and the rough idle is gone. I hate to think of how much it would cost to have a shop try and troubleshoot it. Why is the access panel smaller than the fuel pump?!

Nygee

Its smaller so we can't access it and have to go to dealer 😊