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I'm having an issue with this truck. I have a code P0463. It is Fuel level sending unit sensor circuit 1 high activity. This is what I know so far. at the plug end at the pump there is 4 wirers. The OR/RD is the power from the fuse box, and with a multi meter there is 10.4 volts there, then I checked the ground with a test light, put connecting test light to positive post on battery & touch the pin 2 ground for sender, and pin 1 ground 4 fuel pump motor, then both showed good ground! I didt get no voltage on pin 3 DB/WT that goes from the sending unit to ecm. I'm confused!! is there suppose to be 5vlts on that wire DB/WT from the computer, or does the fuel sender get power from the OR/RD to power the sending unit? I was going to go to the computer on pin 26 C2 connector to test that pin to see if there's 5vlts going out of computer to see if wires bad and not reaching the fuel pump connector. sucks the pin 26 isn't used on computer on the C2 plug end. but went online and noticed on that vehicle it could be pin 33 for the fuel level sensor signal at the computer? If I can find the right pin on this computer, that is fuel level signal. I was thinking of checking for 5 vlts there. then run a jumper wire from the computer to the back of the pin 3 at the fuel pump plug. will plugged in and see if the 5vlts signal drops any on my snap on scanner. It reads 5vlts constinate on scanner. & the instrument gauge says completely empty, and there is fuel in tank. I watched a video with scanner Danner about fuel sending units. I tried what he said to test the integrity of the wiring. I jumped the pin 2 sensor ground and pin 3 fuel level sensor, to see if the 5vlts reading changed on my scanner, when I jumped it, and on scanner it stayed 5vlts! so I took my multi meter to test the pin 3 DB/Wt wire at the fuel pump plug end and didn't get no voltage! I was thinking I should be getting 5 vlts there? so that made me thinking going to computer find the pin coming out of the computer to the fuel level sensor to confirm there's 5 vlts there. this is what I'm confused about if the computer supplies the 5vlts to the fuel lever sender, or does the sender get power off the main OR/Rd wire to supple the power to make the fuel level sender to work then send it to computer?
I hope this isn't confusing on how I wrote things! Any ideas would be greatly appreciated on how to diagnose it and fix the problem , thanks for taking the time reading this! Wiring problems irrigate me a lot. lol Cris
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