No voltage to fuel pump 2002 saburban

MAF mass air flow sensor.

key on engine off will have power to relay for 5 seconds then go out. test at relay plug in for ground comand. with relay removed. need test light off power side of battery to see if command is sent to relay..

You said you checked the pump. Is the pump getting voltage after the 3 or 4 seconds from the relay ?
You get voltage for the pump in the first 3 seconds then none if the engine does not start and produce oil pressure. That is to prevent a fire in a wreck.
Can you jumper the pump relay and hear the pump run past 3 seconds ?

Did you do it like this? Voltmeter: black lead on negative battery terminal, positive lead on one of terminals on coil side- turn key to on, and see if there is voltage for about 2 seconds. If yes, check negative terminal of relay's coil side. If no voltage, move positive lead to other terminal for coil side. Turn key to on, and see if you have voltage for about 2 seconds. If yes, test negative side of relay's coil for good ground. If no signal at either terminal, the signal may be lost from the pcm.

When you turn the key to on, this will prime the fuel system-pump will turn on for only 2 seconds with key in on, and then if no crank signal, pump will turn off (the relay will not stay energized, so no power will go to pump). But when the engine is cranking over, the relay is energized, the coil side will stay powered as long as engine is cranking. After the engine is running, usually an oil pressure switch is tied into the fuel pump circuit, so the relay is no longer needed to put power to the pump. The pump will always be running when engine is cranking, and when engine is running, but the relay no longer is needed when engine is running. See?

P0230 - Fuel Pump Primary Circuit Malfunction Symptoms - Engine Light ON (or Service Engine Soon Warning Light) Possible causes - Blown Fuel Pump fuse
- Open Fuel Pump Monitor Circuit
- Faulty Fuel Pump Relay
- Damaged ECM. P0230 Description The Engine Control Module (ECM) provides ignition positive voltage to the coil side of the fuel pump relay. When the ignition switch is first turned ON, the ECM energizes the fuel pump relay, which applies power to the fuel pump. The ECM enables the fuel pump relay as long as the engine is cranking or running, and crankshaft reference pulses are received. If no crankshaft reference pulses are received, the ECM de-energizes the fuel pump relay after 2 seconds. The ECM monitors the voltage on the fuel pump relay control circuit.
Please go to this LINK for P0300 diagnosis.

You say you have power at the relay, but what part of the relay? If you don't have 12V at the gray wire going to the pump, then maybe the relay is bad. Also check to see what voltage you have on the dark green/white wire, this controls the relay (should be 12V).

You should not see any voltage after the 2-second prime until you actually start cranking the engine. If you don't see power on the grey wire when cranking, try jumpering across the fuel pump relay terminals

the crank sensor is most likely the problem. If the PCM does not sense the engine is cranking then the fuel pump will not turn on. Also just because a fuel pump will run does not mean it will pump fuel.. Jump it while its in the fuel tank to see if it will pump. But still when you turn the key on you only have power to the fuel pump for 3 seconds unless you continue to crank. . If you have a 3 second voltage pulse when you cycle the key on, then spray some quick start or brake cleaner. If it now starts and you know the fuel pump has power then the fuel pump needs replacement. If you don't have the 3 second pulse look at the crank sensor as being the problem,

sounds like new fuel pump time, have a fuel pressure test run to verify..

Could be a relay or fuse, if ok check for voltage down at fuel pump harness over by gas tank ,probe wire's only one will have voltage with key on , then check other wire's should have voltage at one of the other wire's while cranking engine only and should go away when stop cranking, if you do have that voltage replace fuel pump.Good luck.Let us know if you need more help.