Hello

I have an S50FT with a 2.4 GM LPG engine. When I crank it, it will start then die. It showed a 653-5 code which is a cummins code. I cleared the code and retested. Engine light flickered and then began to flash. I pulled the codes via the dash and it was all question marks. Tried to see if I could see the ECM make and it was all question marks. I checked the canbus wires and they were at 60 ohms.

I am leaning towards a bad ECM but would appreciate some advice.