You turn the key to ON and should hear a 2-3 second buzz from the rear of the car, the fuel pump priming. If you do not, the engine will crank but never start. Here is how to find out why.
Pumps die without warning. Cranks but no buzz. Tap the bottom of the tank with the key on, sometimes brushes catch and the pump runs once more. Confirms the pump is dead.
Get a full diagnosis →Always the first check, takes 30 seconds. Locate the fuel pump fuse in the under-hood box, check visually or with a tester. Blown fuses usually mean a deeper problem (short or weak pump pulling too much current), but replace and test.
Get a full diagnosis →Relays click on for 2-3 seconds at key-on. A dead relay leaves the pump powerless. Often you can swap with an identical relay (like the horn relay) to test, $10-$50 part.
Get a full diagnosis →Some ECUs require a crank signal to keep the pump running beyond the initial prime. No crank signal = pump shuts off after 2 seconds. P0335 confirms.
Get a full diagnosis →Fords have an inertia switch that cuts the fuel pump in a crash. Sometimes it trips from a hard bump or pothole. Look for the reset button in the trunk or by the passenger kick panel.
Get a full diagnosis →Corroded connector or broken wire under the rear of the car. Salt belt cars are most likely. Inspect with the rear seat or trunk floor removed.
Get a full diagnosis →| What You Notice | What It Usually Means |
|---|---|
| No buzz at key-on | Pump, relay, or fuse problem |
| Buzz on first key-on then nothing | Pump weak or no crank signal |
| Buzz works after pump tap | Dead pump, brushes worn |
| Recently bumped or jumped | Inertia switch tripped (Ford) |
| Recently blew a fuse | Short circuit or weak pump |
| Codes P0230 / P0231 | Fuel pump primary circuit fault |
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Turn the key to ON, listen at the gas door for the buzz. If silent, check the fuse and relay. To confirm the pump itself is the issue, back-probe the pump connector with a multimeter, 12V at the connector and no buzz = dead pump.
The pump is pulling too much current (worn motor) or there is a short somewhere. Do not just keep replacing the fuse, test the current draw or have a shop diagnose.
Yes. Pull the relay and jumper the right terminals (per a service manual). If the pump runs, the relay or its control circuit is bad.
Usually in the trunk near the rear quarter panel, or under the passenger kick panel. Small black box with a red button on top. Press until it clicks.
Yes. If the engine fires for 1-2 seconds on starting fluid then dies, you have spark but no fuel. Confirms fuel-side issue.
Fuse: $5. Relay: $10-$100. Inertia switch: $30-$150. Pump: $400-$1000. Test cheap parts first.
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