when we tried to start it sometimes it will not energize the fuel pump. You don't hear it come on. When it does come one it will start. But when it doesn't it will not start and gives a check engine light. The codes are all low voltage to fuel pump ect..... We changed the battery and check the battery cables to see if that would fix it. It did not. Where should we look? We really need this fixed.

[2015 Z Force 800 53/Trail EPS]

Start checking for loose or corroded connectors. Check the pins on the ECM as well for any discolored ones.