Voltage Check

I Have a Nissan Pickup D22-B and I have problem with the diesel pump this car have a Zexel NP-VE4 pump . I think that the problem reside in the electrical alimentation of the pump .I want to check the voltage in 4 terminals of the conectors but I don't Know how to do that . I need a diagram with the voltage in any terminal or electrical schema. Any one can HELP ME