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Jared D
Jared D, ASE Certified Technician
Category: Ford
Satisfied Customers: 1355
Experience:  Shop Supervisor at County Fleet
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I have a 2004 F150, no story of issues at all. Out of the

Customer Question

I have a 2004 F150, no history of issues at all. Out of the blue, it won't start. It has to be an electrical issue. It has a good battery, a two month old starter/solenoid. I can hear the relay in the fuse block closing but nothing happens under the hood when I turn the key. Tried it in neutral, nothing. It's not in "theft mode". The ignition switch is closing the relay. Any suggestions? I need help!
Submitted: 9 months ago.
Category: Ford
Expert:  Jared D replied 9 months ago.

Have you checked any of the fuses yet?

Fuse #34 in the under dash can affect cranking on this model if it is blown.

Let's start thee.

Also, I assume headlights, dome lights, radio, etc still work?

Customer: replied 9 months ago.
all electrical components still work. Fuse 34 is good
Expert:  Jared D replied 9 months ago.

Do you have a scan tool?

Customer: replied 9 months ago.
Nope, there's no fuses blown and I don't have access to a diagnostic tool tonight.
Expert:  Jared D replied 9 months ago.

If your PCM has burned out, you won't be able to get a scan tool to communicate. Also, has the starter ever been replaced? Could you have someone bang on the starter with the handle of a hammer while you try to turn the key. This will tell you if the starter has gone out.

Expert:  Jared D replied 9 months ago.

If you have a multi-meter, here is the fault tree from ford to test for a bad PCM without a scan tool:

1. Check for battery voltage at the fuel injectors on the Red (RD) wire at any fuel injector connection with the ignition switch in the Run position.

2. If the circuit does not indicate battery voltage, check fuse 2.34 (20 amp) of the central junction box for a blown, missing, or poorly connected fuse.

3. If fuse 2.34 has no power to it with the ignition switch in the Run position, check fuse 2.28 (5 amp) of the central junction box to verify it shows power with the ignition switch in the run position. Also remove the powertrain control module power relay from its holder in the central junction box and verify two of its terminals show power with the key in the run position.
Install a jumper wire between terminal 3 and 5 of the relay to determine if power comes back to fuse 2.34 indicating a defective power relay.

4. If the RD wire of the fuel injector shows full battery voltage, check the Brown/White (BN/WH) wire of the fuel rail pressure sensor to verify it shows 5.0 volts with the key in the run position.

5. If the BN/WH wire at the fuel rail pressure sensor shows to be less than 4.9 volts with the key in the run position, disconnect other powertrain control module sensors fed the 5.0 volt signal and look for the voltage on the BN/WH wire to come back to 5.0 volts indicating a shorted sensor. This would include the power steering pressure sensor, the throttle position sensor, and the fuel tank pressure sensor.

6. If the vehicle reference voltage signal is still low with these devices unplugged, verify battery power is present to the powertrain control module on the RD wires at pins 51, 52, and 53 of the C175b (middle) connector. Also check the BN/WH wire for a short to ground in the harness before condemning the powertrain control module.

Expert:  Jared D replied 9 months ago.

Please let me know if you need any additional info.

Also, don't forget to rate if you no longer need assistance.

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