insame1

Hey all, cross posting this sine th c55 and the clk55 are nearly the same car.

Im throwing a p0446. I took it in to an indy who suggested I replace the evap switch under the hood, gas cap and valve cover gaskets. I did all that and got the code again. I took it to MB of Austin and they said it was the charcoal canister, shut off valve and MAF I replaced all of those too and still get the code. They were all replaced with oe mb parts. What is there left to do? Oh. I replaced the harness at the shut off valve also.

rilonprime

Assuming it's a leak, smoke test the evap system. Once found that a vacuum tube nipple on the charcoal canister cracked and I wouldn't have ever known until I smoke tested the system, seeing wisps of white smoke coming from the back right of the car. Evap codes suck because it can be caused by so many things, however I'm not sure if the valve cover gaskets would be a culprit. Good luck on your search!

insame1

yeah I did the gaskets because they were leaking so bad the smoke test wouldn't work. I replaced the pressure sensor today so if that doenst work back to the smoke test.

dorimaster

hoses that come from the valve covers always leak, AND the top of the fuel sending units always leak. I JB "welded" mine and stopped the leak and codes, just flip up the back seat and remove the 6 8mm screws on the cover to see if thats your issue

insame1

I replaces the fuel sender less than 6 months ago due to cracking. Also all breather hoses are new.