Fuel pump diagnosis is more than pump power
A no-start with no fuel pressure can be caused by a failed pump, missing relay feed, missing relay command, open fuse, poor ground, crash/inertia switch, anti-theft logic, or PCM control issue.
A fuel pump relay wiring diagram shows the control side, load side, fuse feed, pump feed, module command, and ground path needed for a clean test.
What to test before replacing the pump
Check relay terminal feed, relay command, output voltage under load, voltage drop on the pump ground, connector condition, and whether the PCM is commanding the circuit.
If voltage appears for only two seconds at key-on, the diagram helps identify whether the system is priming normally or losing command during cranking.
How to use this topic
Search the intent
Start with fuel pump relay wiring diagram when the symptom needs exact circuit context.
Choose the vehicle
Narrow the catalog by year, make, model, and system before purchasing.
Verify before repair
Use the diagram with meter testing, connector inspection, and safe service procedures.
Questions technicians ask
Why does the fuel pump run for only a few seconds?
Many vehicles prime the pump briefly at key-on, then continue pump operation only when the PCM sees a crank or run signal.
Can a bad ground look like a bad fuel pump?
Yes. A weak pump ground can show voltage with no load but fail under current, so voltage-drop testing is important.