Truck will not start

truck broke down on the freeway last night on the freeway. I was going down the road and all of the sudden I lost power. Truck does turn over I Was thinking it was my fuel pump. Found out that I am getting coil voltage to the COPN relay but not getting the line voltage to it from the EFI relay. I jumpered the fuel pump relay terminal last night and got the pump to run so I know the pump is good. All fuses are good. Has anyone else ever had this problem? Any help would be appreciated.

 

What year/engine is in this thing? Does the truck run when you jumpered the fuel pump relay?
What else have you checked? Spark? Injector pulse? Any codes?
Let us know.

 

It’s a 2006 / v6. Noticed last night I was not getting power to the fuel pump relay. I jumpered the relay and heard the pump turned over but did not try and start it. EFI relay has 11.8 v on the coil of the relay and on the line side. I have 11.8v on the coil side of the COPN relay and nothing on the line side and the same with the fuel pump relay. I did not check anything else seeing as I am not getting power to the fuel pump. If I was getting power to pump I understand that I would have a bad pump

 

Here are the schematics I have been using. There is a connection point between EFI relay & COPN relay schematic show it as a grey square just below the EFI relay not sure where it is located.

 

Did you check for codes. From your description the Body ECM is not switching the ground for the COPN Relay to allow it to energize the coil.

 

Easy enough to check, test light to battery positive and then pull the COPN relay and connect to terminal 2 in the relay socket.

Crank the engine, if it lights up you have ground control - Replace relay and recheck.

If it does not light up, you have a PCM or wiring issue.