I have a 06 cobalt with a no start no crank situation. I have low speed com but no high speed. Allot has pointed me to the vcim but my car has no OnStar thus no Vcim if I am understanding correctly. I have pulled the back deck and there is no module on the back deck. Any and all help would be nice. When doing the ohm test on the obd connector I get 5 ohm unless I unplug the bcm the the reading goes to 120 ohm's.. I was warmed the vcim is a pass thru on the high speed and can cause this communication issue I am having.

 

Is this a car you just got? Something that happened after a type of service, event or just suddenly after shutting the car off one day?

 

previous owner said the car stalled would not start back up they said it was a bad body control module replaced it still no fix another shop replace the PCM. I'm still in possession of a old ECM module and BCM

 

After some research I have found that the 120ohm resistor is not residing inside of the BCM for some reason my steering control module is metering out at 120 ohms and My ECM testing out at 120 ohms at looking at the wiring diagram that is the first and last device in a high-speed gmlan bus. And the testing on the steering control module was done with everything else unplugged