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Discussion Starter #1
Hey Everyone,

Got a 240k mile '98 c230 that has been running fine. Recently did a bunch of maintenance items + k40 relay + coilpacks. Now the car is not even cranking, and I can't seem to get power to the OBD2 port leaving my scanner useless. When I first got the car it would crank but not start, eventually it was due to a dead k40 relay, ordered a brand new one and replaced it. I'm hoping it isn't the relay again since I just replaced that recently...

Symptoms:
1. Car doesn't crank, battery is okay(I even provided extra juice from another battery in case it actually was low)
2. Driver side knee area OBD2 port doesn't seem to be getting power to it. My OBD2 scanner won't turn on(it has a bunch of LED lights that flash when connected). I even plugged this obd2 scanner into another c230 and it's able to read that car.
3. When the key is turned to on position, the radiator fan starts spinning max speed...not sure why.

Is there an OBD2 fuse or ecu fuse I need to check?
 

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1995 C280 (165K mi)
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1,549 Posts
The k40 relay could be suspect here. Recheck that.

Why did you do all this work if it was running fine?
 

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8 Posts
Discussion Starter #3
Initially when I got the car it was a no start but it does crank issue. That was about 3 years ago. Found out it was the k40 relay that caused it. Replaced that and drove it around. Shortly after driving around I did a full tune up(oil change, spark plugs, fuel filter, etc). Eventually two of the coils went out so I replaced both. Camshaft and crankshaft position sensor eventually went out and I replaced those as well. Car is now at 240k and has been going strong ever since, until today.

I disconnected the battery at both terminals and that allowed my obd2 plug in to finally flash and show lights, but I’m still unable to connect to the ecu to read any codes, if there were...help please!


Car is still at a no crank no start symptoms with radiator fan running at max speed when key is turned to on position
 

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1995 C220
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2,775 Posts
Could be a security issue with the key, but have you checked to see if the ecu is being supplied with power and ground?
 

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Discussion Starter #5
I’m going to check and swap the k40 relay module...maybe the fuse is faulty...

the key works though. It turns onto the on position with the click, and shiftlever position indicator light turns on.
 
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