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Sorry it took so long, I don't get home from the shop until the afternoon/evening. There are actually 2 sam modules, the rear sam controls and sends the signal from the fuel level sensors to the instrument cluster. Was the front sam replaced? Was just the sam module or the entire sam with fuse and relay box replaced?
The sam module actually plugs into the backside of the fuse and relay box. I usually recommend replacing them in pairs because the fuse box can get shorted internally.
Yes, I have seen it before. It is a CAN network issue, usually caused by the front sam/fuse and relay box. I've always just replaced them in pairs because I have seen one damage the other. It is a little weird that your fuel gauge is dropping...that signal is sent by the rear sam.
Well, first double check that the fuse and relay box was replaced with the front sam. If it wasn't, I would make sure you replace that first.
Well 2 things. The fuse and relay box is just that, a box. The sam module slides into the backside of it. I suggest replacing both of those parts at the same time.
Used ones are a lot cheaper on ebay. Are you using new parts?
Did the sam module have any fuses and relays on it?
Or was it just the module?
Ok, you can usually find them like this. http://www.ebay.com/itm/Mercedes-W203-C230-Relay-Module-Includes-SAM-Module-and-Front-Fuse-Panel-Genuine-/141735929787?fits=Year%3A2003%7CModel%3AC240&hash=item21001ea7bb:g:wHQAAMXQfFJRJvGg&vxp=mtr
This is the complete assembly you need.
It won't be a separate question. Let me know how things go.
I may not be able to get back to you until the afternoon, evening though.
Yes, if its an easy question for the average expert. Your problem needs a mercedes specialist with more intimate knowledge of your car's systems.
Ok, good luck!
Yes, that is the front sam for sure. Did you have the same exact symptoms with the front sam replaced? You said that someone put one in and then removed it when it didn't fix it, correct?
Did the mechanic every give you a copy of the "quick test" or "short test" if he did one? If not, is it possible he could get you one? I would like to read all the can fault and event codes. I should to be able to determine a lot more just by that test.