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Ron
Ron, ASE Certified Technician
Category: Ford
Satisfied Customers: 34765
Experience:  23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs
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I have 2008 ford f250 superduty 5.4,I lost ground going to

Customer Question

I have 2008 ford f250 superduty 5.4,I lost ground going to fuel pump
JA: Have you ever replaced the fuel pump, or is this the original?
Customer: Original
JA: Are you fixing your F250 yourself? What have you tried so far?
Customer: I changed fuel pump driver module
JA: Anything else you want the mechanic to know before I connect you?
Customer: I jumped green wire with blue tracer with white tracer fuel pump kicks on and runs but then I get p0191 and p0462 code
Submitted: 8 days ago.
Category: Ford
Expert:  Ron replied 8 days ago.

Hello. My name is ***** ***** I am happy to assist you today. Give me just a moment to review your post, and I'll be right back with the help you need.

Expert:  Ron replied 8 days ago.

Do you have a good ground to the FPDM at pin #3 (blue/gray ) wire?

Customer: replied 8 days ago.
No
Expert:  Ron replied 8 days ago.

The Blue/Gray wire at FPDM (pin 3)is the dedicated ground for the FPDM, grounding to the driver side of the frame at G401, near the carbon canister. Have you check it to see if the connection is clean and tight at the frame?

Customer: replied 8 days ago.
I just ran a wire off the frame to the blue wire now I have a ground
Expert:  Ron replied 8 days ago.

Okay dose the fuel pump now engage with the key on and engine cranking?

Customer: replied 8 days ago.
No the fuel pump does not kick on
Expert:  Ron replied 8 days ago.

Okay you are going to need to go back and recheck the circuit to the FPDM and out of it to the fuel pump. I have enclosed the steps in the link below so you can do this.

https://dl.dropboxusercontent.com/u/104923897/Fuel%20pump%20Apr%2017.pdf

Also see the Fuel pump wiring diagrams for testing reference in these link. Have a look and see if this will help you get this resolved.

https://dl.dropboxusercontent.com/u/104923897/FP%201%20Apr%2017.pdf

https://dl.dropboxusercontent.com/u/104923897/FP%202%20Apr%2017.pdf

Customer: replied 8 days ago.
I tested for power at the fuel pump driver module and I have no power at the violet/white wire
Customer: replied 8 days ago.
Cancel that I have power forgot to turn key on
Expert:  Ron replied 8 days ago.

That power come from the fuel pump relay so yes the key dose need to be on So if you have power now then your okay on that wire.

Customer: replied 8 days ago.
I tested everything at fpdm everything looks ok,I did ground out the white/brown wire at fpdm fuelpump kicks on
Expert:  Ron replied 8 days ago.

Are you sure you do not have a defect FPDM?

Customer: replied 8 days ago.
I hope not I just bought it,is there a way to test it to see if it's good?
Expert:  Ron replied 8 days ago.

If you have power and ground into it then there really is not other reason why it will not turn the pump . I would run back through the steps once more just to be sure you did not overlook something.

Customer: replied 8 days ago.
At the fuelpump connector which wires are for power/ ground for pump and power/ ground for fuel gauge
Expert:  Ron replied 8 days ago.

The yellow/green id the power feed to the pump out of the FPDM and the ground.

See the fuel gauge circuit in the link below. The sending unit wires at the pump are the yellow/violet and the green/blue.

https://dl.dropboxusercontent.com/u/104923897/Fuel%20sender%20Apr%2017.pdf

Customer: replied 8 days ago.
Ok going to check that out after lunch, now if the fpdm is bad would that make code p0462?
Expert:  Ron replied 8 days ago.

The code P0462 indicates a problem with the fuel gauge and or the sending unit and dose not affect the Fuel pump or the driver module.

Customer: replied 8 days ago.
The fuel pump relay, which fuse panel it it located in? Under hood or right kick panel
Expert:  Ron replied 8 days ago.

On your F 250 its located in the under hood panel. See the diagram in the link below.

https://dl.dropboxusercontent.com/u/104923897/fuel%20pump%20relay%20APR%2017.pdf

Customer: replied 8 days ago.
Ok I changed fpdm seems to be working good now checking fuel gauge, testing power at fuelpump connector I have power at the white/ brown and yellow/grey wire nothing at green/ orange yellow at brown wire
Expert:  Ron replied 8 days ago.

The sending unit wires are the green/brown (signal return) and the yellow /violet signal out. In most cases this code you are getting set due to a failed fuel tank sending unit.

Customer: replied 8 days ago.
Should either one of them have a power or ground
Expert:  Ron replied 8 days ago.

The signal in ware will have a low voltage reading.

See the pinpoint test steps in the link below. Start your testing at test A 1.

https://dl.dropboxusercontent.com/u/104923897/Pinpoint%20test%20A%20Apr%2017.pdf

Customer: replied 8 days ago.
I have low voltage at the yellow/violet wire nothing on the green/brown
Expert:  Ron replied 8 days ago.

That in most cases means the sending unit has failed.

Customer: replied 8 days ago.
Can you just change the sending unit for the gauge or do you have get the whole thing
Expert:  Ron replied 8 days ago.

You can just replace the sending unit.

Expert:  Ron replied 8 days ago.

You can also check the resistance reading on it as well to verify it has failed. . The sending unit should indicate a reading of between 10 ohms (full tank) and 180 ohms (empty tank). If the resistance is out of range low or high, replace the sending unit assembly.