HelloI'd check that you're getting full power to the glow-plugs, they pull a lot of current so take care when checking but see if the relay is clicking when the ignition is turned on first and also check the fuse if this is OK check to see if the engine earth strap is also OK.If the plugs haven't been changed in the last 20K then they may have to be replaced.
You can test the glow-plugs with a multimeter by measuring the resistance across the plug ( between the power connection and the body) it should be around 4-8ohms if its tending to infinity / open circuit the plug is faulty or by using a clip on current clamp, either on the supply wire to glow plugs or onto engine earth, with glow plug light on you should see 15-20amps for each glow plug fitted, 4 cylinders would be approximately 60-80amps.
thanks for the extra info
I'd consider replacing the glow plug module
The original part number is(###) ###-#### ***** is replaced by a new part number(###) ###-####and can purchaseed from http://www.genuinemercedesparts.com
yes that is the same part
OK if thats fine then I'd check the wiring and connection to this part as they can collect water in the back of the connection which then shorts them out
also worth checking the cleanliness and tightness of the earth connections to the engine and battery
are you getting any power to the plugs? as this will show if the module is being poowered up or not
if there's no power coming in then I'd suspect either the ECU isn't switching it on so next check the condition of the fuses for the ECU ( also called the ECM or PCM) and for the glow plugs
if these are all intact and you're confident the earths are all OK then the ECU may have to go off for testing as the next step
the fault codes
ETC – Electronic Transmission ControlEvent C100 – No CAN message was received from engine management control unit.Event D10B – No CAN message was received from engine management control unit.
so event logs like this are separated into different areas and in this case originate from the transmission
a lack of communication usually means a wiring fault between the ECU and transmission so the non start could well be down to this issue and it would be worthwhile disconnecting and cleaning the gearbox electrical connections