BullSae

Need you help on '99 ML 320 58K miles. CEL came on with P0442 code and no other codes found. Erased it a few times but keep coming on. I've spent a couple of hours here and understood what to check. Thanks for your posts !!!

Gas cap seems very tight, so I guess it could be vac line or purge valve (may be something else - pls tell me). But where is the purge valve and what it looks like? I guess somewhere under the hood but couldn't figure out. Is it easy to replace if needed?

Any comment and advice would be appreciated. Thanks.

mercedestech1

The system is setting this code because the system is not leak tight. This could be caused by numerous problems-in this situation it's a better idea to take it to a dealer. They can moniter the tank pressure sensor and see exactly how much it's leaking down. Then they will crimp off hoses/replace components to see exactly where it's leaking. It may not be a component-it might be a seal or a line. In most cases the purge valve will not cause a minor leak-they will cause a major leak. If you want to replace it anyway-look for the throttle linkage under the hood-the plastic bracket that the throttle linkage is on-the purge valve is connected to this with a rubber bushing. The canister shutoff valve is above the spare tire under the car.

BullSae

If that's the case, I think this is not something that I can do as 1-2-3 diy. Ha! When I visited my MB dealer last time for something else (CEL started around that week), I asked about the code and they told me keep eyes on how it goes for a while and if the code keeps coming up, then I will need to replace PV. I think your advice is more reasonable and agree to nail down the leak first....
Anyway, I will try to find PV. Thanks.

jmarkson

Hi I was wondering if anyone could shed some light on my situation. About 3 months ago I replaced my fuel pump including the fuel feed line. I now have this code saying there is a leak. I checked the access panel and saw a little bit of gas. I fixed the lines and drove it a few miles and saw no fuel. But still the code. The fuel loop line connector was cracked a little but seemed to hold tight and I saw no leaking. I now have this code should I replace the other 2 lines? I have ordered them to see if that resolves the problem. Any other ideas as to what it might be?

Secondly-I have a P0700 code also. I know this is a generic transmission code but was interested if anyone else had the code and how they corrected it. I am trying to resolve the P0442 on my own. I have an appointment at a local shop known for Mercedes mechanics, I am taking it to them this weekend to have it inspected. But would like to know what I might be looking at first.

Thanks,