If you have wiring diagram it's not too bad to test, start by unplugging sensors and check resistance, open circuit will be no good, then check for same at ecu plug to confirm wiring ok, if pump runs and cuts out when up to pressure then that should be ok, another common problem is the level sensor on the cap or wiring to it. The system itself is pretty simple and not hard to troubleshoot. An open circuit sensor is usually the culprit, front plugs are under wings and rear are under back seat.