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Got this CEL, and wouldnt you know it, right before my emissions are due. This is for a 2008 CLK550.
I replaced the original purge valve on the charcoal canister with another identical one from a clk55, cleared codes, waited for a few days, and the code P2422 came back again. Im 99% sure that the purge valve from the clk55 worked before i removed it. Could this be a problem with the charcoal canister? I did not replace that, as the bracket from the clk550 and the clk55 are not the same.
Is this part a valve or an air pump? Can I take it apart and clean it? It looks possible, but I dont want to mess it up before asking.
If the charcoal canister is plugged, would I just be able to remove the valve from the canister and would it pass codes that way?
I think this is the same code I have periodically on the ML350. I replaced the valve with a brand new one and it still throws the code sometimes. Researching it in SDS says that it can also be a problem with the pressure sensor on the fuel tank. I guess the ECU doesn't actually have direct feedback from the valve that it is open or closed, but instead relies on the relative pressure in the tank reported by the pressure sensor. I think it may be a bad pressure sensor. Since the code states that the valve is closed, it's not going to be a leak because with it closed, the pressure would be high, not low.
Thanks for looking that up. This actually makes sense possibly. When I replaced my fuel pump, I left that sensor laying out in atmospheric air.
The reason I left it uninstalled, is the plastic cover did not look like it had any type of pass-thru to the tank. It was just a solid piece. I'll have to take the back seat off and see what I missed. That must be it tho.
Thanks again!
Originally Posted by Rudeney
I think this is the same code I have periodically on the ML350. I replaced the valve with a brand new one and it still throws the code sometimes. Researching it in SDS says that it can also be a problem with the pressure sensor on the fuel tank. I guess the ECU doesn't actually have direct feedback from the valve that it is open or closed, but instead relies on the relative pressure in the tank reported by the pressure sensor. I think it may be a bad pressure sensor. Since the code states that the valve is closed, it's not going to be a leak because with it closed, the pressure would be high, not low.
So the fuel pump I ordered did not have the fuel pressure sensor "port" built into the top of it, pictured below. I guess one option would be to drill thru a spot in the fuel pump. Im not really liking that option. You'll see in the picture when I installed it, I didnt know what to do with it, so I just zip tied it into place. Im surprised it didn't throw a CEL earlier. Since it didn't, I just figured it was OK. So besides drilling, Im thinking over my options.
Last edited by 91ser; Oct 12, 2018 at 12:51 PM.
Reason: Changed Drip to Drill
I was looking at the S550 design. It has the fuel pressure sensor back by the charcoal canister. If I extend the electrical wires, I could splice into the soft line running into the charcoal canister. Would the line pictured below work? I would think so, as again, it looks like the 550 design. Thoughts? I'm hoping this works.
T into the line here to pull fuel pressure from the tank?
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