Hi, I have a 2003 CLK200 Kompressor (W209) that shuts off suddenly when it gets hot.
While driving, the engine dies as if the ECU loses all power to motor, no response to key. Sometimes it starts when i try, but usually i dont get connection even with tester and I have to unplug and replug the ECU connectors to get it working again. Code P0365 (camshaft position sensor B) shows up often and when disconnected magnets i got p0020, p0010 few times. I also got p0606 when i swap magnets place. Once I found a darkened ECU pin going to the camshaft magnet, but cleaning didn’t help. Disconnecting the camshaft magnet doesn’t prevent the issue, so that’s likely not the main cause but it does something because it runs longer when i do something to it ( atleast i believe )ECU has been opened and visually checked and no damage found.
Has anyone seen something like this? Could it be ECU overheating, bad ground, or faulty relay? Any help is appreciated
I’m really stuck!

 

still not working, anyone know a fix to problem?

 

Could be one or more of the cam magnets leaking into the ECU through the plugs/wires (Electricity conductivity helps the oil travel). I had that issue on my 09 S550. Only one of the magnets were bad and full of oil in the plug area. I cleaned the ECU and the affected ECU plugs with electronic cleaner. It could be there is oil that made its way into your ECU through the pin or the connector on the wiring harness has some oil in it. There are diagrams online that show which pin is for what on these ECUs.

 

Hey, thanks for answer. I changed both magnets and cleaned ECU plug connectors with electric cleaner. Opened ECU and there wasn't any mark of corrosion or oil and it was very clean, Should i still clean it with electronic cleaner?
I haven't still figured out what is causing the problem because i have cleaned all what i can think of. There was oil in camshaft sensor and i cleaned it but still i get p0606 when ecu shuts off. BTW this happens usually when engine/ecu/plug is heating up and then the problem starts.
Does someone know anything to try clean or change to fix this, thanks!

 

I never had that specific problem, but I have done small repairs to electronics components, car-related and otherwise, using hints and techniques that were picked up from electronics repair pros, with some success. Most will always start a repair by cleaning everything, using, in some cases, special products, but many use also isopropyl alcohol, and acetone (which is best for grease of any kind). The reason is that thin films of dirt or grease may not be apparent visually, but still affect electronics. These products must be used with some care, as both will dissolve thermal pastes and compounds, and acetone will attack some kinds of plastics (ABS is one). In your case, this applies to the plugs that connect to the ECU, and, if present, to the mounting posts of the PCB, if made of plastic.

So, when there are plastic components to be exposed to acetone, I always test beforehand, using a cotton swab damp with acetone, and touching a non-essential surface of the plastic part, and then checking, under high-magnification, for ANY kind of reaction or change to the plastic surface.

If, after a few minutes and several rubs with the acetone-damp cotton swab, there is no visible reaction, it is safe to use acetone to clean everything. I use a fine brush, lightly damp, for the small corners, and an old toothbrush for the general surface. The first 2 passes usually only move the dirt and grease around, so I repeat this 3 or 4 times, checking under high magnification for the lingering presence of dirt or grease.
This is how I clean electronics and their related parts, including plugs. This does not remove chemical corrosion, but it will make it more visible.

So, if I were in your shoes, I would clean *everything*, 2 or 3 times, starting with a check for dirt or grease: using a clean, dry paper towel, rub it lightly across all surfaces the are accessible, and check, after each rub, if there is *any* kind of contamination of the paper. If there is, the component or part must be cleaned. I would remove the ECU from the car and disassemble completely it in the bench, using anti-static precautions, and clean *every* part thoroughly, even the non-electronic parts, like the inside of the case or mounting pylons. For the plugs, the best way is to use a spray of electronic cleaner, and blowing it immediately (before the product dries and evaporates) with compressed air. I'd do it 2 or 3 times in a row, and then check, with a loupe and the paper test. I would do it from the front and the back of the plug, if accessible.

If nothing else, this will insure that the problem is not dirt or oil, but something else. Probably electronic, or bad sensors, etc. Unfortunately, I don't know enough to help you there...

Disclaimer: I am a DIY amateur at this stuff, so take all this as a "best effort to help, but I know very little about this" kind of value. Do any of it at your own discretion and risk.

Good luck, and let us know how it works out for you.

DF