I do not know what epc stands for, if it stands for electronic parts catalog then I believe you are putting your faith potentially in a system with errors as I found (read on). It is what your original manual recommended that matters. Also I assume you have the correct Bosch/MB wires so that resistance is correct. By the way, I did not read all of the previous posts but make sure your multimeter is high impedance or you may damage something, I use a fluke 88 with 10 Megaohm impedance.

I did a post focused on this plug issuea few months ago. Mercedes, in their parts system, also recommended w9dc0. However that is NOT the original part for the car nor the plug the car previously used. I called Bosch and they agreed with me and did not recommend the plug for the car. I called MB America and they were arrogant and would not address Bosch's or my comments. To this day, MBs parts system still says w9dc0 despite the fact that Bosch does not recommend it and it is not the original plug for the car. Several mechanics I spoke with also,agreed with me. Since my posts here and on another group I have received mixed responses-- it solved some peoples problems and did nothing for others. Some engines are probably more sensitive to this style of plug which I believe is colder.