MB S320 CDI won’t turn over cooling fan on full, fixed with Star SDconnect C4

Post begins with the car died problem on Mercedes S320 CDI, followed with SDconnect C4 recommendation to troubleshoot this problem by senior technician, finally find out the problem is the bad ECU with the aid of MB STAR sdconnect, then problem is sorted out. If you have the same problem with the same car models, go on reading.

Car symptom:
Engine warning light came on and the car just died.
if I put the key in and turn to pos 2 the only lights which come on are ABS and a red triangle with a car in the middle, (no glow plug light, or engine light etc), I can NOT hear the fuel pump and the engine Cooling fan starts and runs at full speed and is quite loud, I turn the key to start and nothing happens no crank, just silence.

I went through most of the obvious fuses and cant see anything blown.

What I tried to do:
I connected it to my carsoft v12 diag kit and ibm t30 laptop I have, there seems to be no communication with ‘ME’. I have checked the ECU connectors for corrosion, clean as a whistle.
I keep all my drain plugs clear because I know that water Ingres is a problem on this car.
My past experience with water problems in electrics is you get intermittent problems but this happened suddenly.

Problem Analysis and what to do:
1) Optional possibility: Failure to communicate with an ECU can be a can bus fault as well as a failure of the unit as well.

With MB Star eg. SDconnect C4, you can diagnose the canbus system for errors,
sometimes the distribution box under the passenger foot well needs replacing or resetting to allow the canbus system to send information around the vehicle again.

Where can I find info on the “star” diagnostic kit??
I recommend www.worldobd2.com, its MB SDconnect C4, I bought it one year ago, and working perfectly except the installation error when I got it. I have use it even reset air filter, etc.
Read detail info at: http://www.worldobd2.com/wholesale/mb-sd-c4-star.html

Then, I did check the can-bus for corroded/loose connections. The thing is when I unplug the can bus the key in the ign does not turn at all, but if I unplug the ecu I get exactly the same symptoms, which may point towards the ecu.
So, the senior technician is more sure A session on MB Star is recommended

2) Another one optional possibility:
The senior technician advised possibly dead control unit. The fan going full chat is a fail safe to stop the engine over heating. I recommend going to a reputable Merc specialist and get some proper diagnosis.
Then, I put a multi-meter on the ecu plugs, it was reading just under 6v with ign on so I am guessing the ecu is receiving power, which might rule out the sam unit.
I am going to drive to ecu doctor in Plymouth near me with the unit and get them to test it for £35 which is worth it to rule it out.

Finally, the problem solved with the aid of MB Star SDconnect
Just to give an update in case someone else is going through the same symptoms. It was a bad ECU after I diagnose with MB SDconnect C4!,
I sent the ECU off to ecu doctor, they copied the data over to a good unit, got it back plugged it in, ignition on, glow plug light came on CAR STARTED!. Took it for a drive: flawless.

MB Star SDconnect is great to have as an aid(I will get it soon) but if you an idiot like my local merc indie happens to be then it becomes useless. 10+ problems I have sorted on a modern merc without it.



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