'97 C230 ECM fault
Ok... the car came in the shop missing hard... had a code for mass air flow (which we easily solved by putting the breather tube back on) and a #1 misfire code... We scoped it, n replace the bosch +4 plugs that the owner had installed himself just for grins n giggles. Next we gave a listen to the injectors, and bingo... the # 1 injector was dead... we then checked the connector with a noid light and it flashed... SO, rether than just put a nes injector in it, I pulled the fuel rail and swapped injectors 1 n 2. Hooked everything back up and the trouble code followed the injector... (misfire code on # 2) Here is where it gets weird.
IWe had to order the injector and when it came in that evening i installed it in place of #2 (which was the bad injector that came out of #1) Fired it up, and it STILL HAD A MISS !!!
I rescanned it and got another #1 misfire code... go figure. but in addition to the misfire code, i got an injector #1 circuit malfunction code. (i'm really curious as to why i would get that since i had a blinking noid lite in the beginning. Nevetheless, and correct me if I'm wrong, but the ECM actually grounds the injectors thus creating the injector pulse. SO, we found a salvage unit (since a new one is $2100 and sent my customer into shock) Well, with that one installed, the car wouldn't even crank. Put the old one in and it starts right up... Tell me I'm right in suspecting the ecm at fault here... there is batt voltage to one side and continuity from the connector to the ECM....