srivet02

I have an intermittent check engine light on my 2007 E550, so I purchased an Actron CP9580 scanner to diagnose the problem. Unfortunately, there seems to be no power at the OBD port, the scanner won't power up. I immediately checked the scanner by connecting it to my Dodge pickup - works like a champ. When my wife returned home, I plugged in to her 2006 C230, and also works, so it's not a scanner not compatible with Mercedes issue. First thing I thought to do was check to see if the fuse protecting the OBD port was blown, but I can't find any documentation in the manual or in the car about which is the appropriate fuse.

Anybody know the location of the fuse that protects the OBD port?

mkhurley

There should be a fuse chart in the compartment in the drivers side fuse box area (page 470 in the manual). If it's not there I can pull mine and look for the fuse when the wife gets home with the car.

srivet02

The fuse map in the passenger compartment fusebox doesn't mention the OBD port, couldn't see anything that looked like it was describing the port..... other than a couple of fuses listed as "engine control electronics" or something similar..... both of them were intact as measured with a DVM. There isn't any similar chart in the trunk fusebox, so I'm thinking maybe the appropriate fuse is there.

Very nice looking vehicles in your pic........

mkhurley

I would say it's probably the "Diagnostics Socket" Fuse 30 in the passenger compartment fuse block, second from the bottom left 7.5A.

Thanks, I enjoy them both.

srivet02

Aha! That's gotta be it. My copy of the fuse chart was creased and faded at just the point where it said diagnostics socket. Thanks so much for the advice and the copy of your chart. Really appreciate the help.

srivet02

Yup, fuse #30 is open, I'll pick one up tomorrow, should be able to read diagnostic port then.

mkhurley

Might be one in the toolkit in the trunk....

WEBSRFR

I hope it is not the dreaded engine cog issue. I had that mine with my E550 and it was a VERY expensive repair, but covered under warranty. My light went away also but the dealer was able to pull the code and determine what caused it. It could be something as simple as the gas tank lid not being shut properly but please rule out for sure it is not anything serious.