I am getting lower voltage readings at teh ecm compaired to the batteries. Is this normal??

Low batterys = 10.5 volts at battery / 9 volts at ecm

charged overnight batteries = 13 volts / 10 .2 at ecm

Is this normal?? Troubleshooting a no start, realized no power to fuel pump, or even the inertia switch for that matter and reference voltage for sensors is showing .1 volts. I dont have a high end code reader, just a bluetooth one. no codes from that. Im still trying to find a detailed wire color diagram for this truck. I have the coffee table bible one ,but it does not show wire colors.

Any ideas or experiences??

Thanks for the help

 

How are you reading voltage at the ECM???

 

Well since i cannot get the bluetooth reader to talk. i unplugged the center connector on ecm and used a volt meter on the second pin from the top right as a reference. (it was the only pin that had more than 1.5 volts on it I could not find a pinout / wiring diagram for the ecm.

 

Woot :0 I found a chaffed wire in the bundle behind the fuse box!!! truck now talks to ecm and getting fuel still no start but we are closer !!!