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Hi, new here and I need help. Just got an 03 C4E kodiak crew cab LB7 automatic. Problem is truck seems to be using fuel out of rear tank only, along with the gauge. I thought engine pulled fuel from front tank only. rear tank is for transfer to front and the gauge worked only on the front. Anybody had this happen. Oh no codes coming up on OBDII. thanks greg
 

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You should have a switch that swaps between front and back tanks. This switch has been on the dash on the few I have looked at.
Pete
 

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have not found one yet. I was under the impression that it would self transfer from the rear tank to the front with the frame mounted transfer tank,
but then I am not sure why the gauge is reading the back.
 

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Hi, new here and I need help. Just got an 03 C4E kodiak crew cab LB7 automatic. Problem is truck seems to be using fuel out of rear tank only, along with the gauge. I thought engine pulled fuel from front tank only. rear tank is for transfer to front and the gauge worked only on the front. Anybody had this happen. Oh no codes coming up on OBDII. thanks greg
I'm working on a 2003 C4C right now , and on this unit , your scenario would be impossible , The rear tank is plumbed with 2 lines into the vent of the front tank only .

The gauge reads both tanks and balances them . There is absolutely no connection of the rear tank to the engine or fuel module of the front tank .

There is a in line pump between the rear and front tank that is commanded by a fuel control module forward of the front tank & mounted on the frame .

If the rear sender is unplugged then the gauge will only read up to half , even when full ! Hope this helps , maybe your truck is different , but this is how everyone I have seen is set up when they are 41gallons !
 

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have not found one yet. I was under the impression that it would self transfer from the rear tank to the front with the frame mounted transfer tank,
but then I am not sure why the gauge is reading the back.
This is how the 2500/3500 dual fuel tanks operate-- fuel is transfered from the rear tank to the front/side tank. All engine fuel is pulled from the side tank.

Not certain on the 4500 Kodiak trucks.
 

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computer reads both tanks an bal. fuel from rear to front tank (no transfer switch) as needed. pick up to engine is in front tank only no engine supply in rear tank.

Had same prob in my 05 Fuel Gage went dead an wouldn't transfer fuel from back tank
had to replace the fuel transfer pump on Driver side frame rail. gauge came back on line instantly an rear tank transfers fuel as it should.easy fix about $75.00 for t-pump.
 

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I have a2015 3500 HD, just bought it and cannot get any fuel in the front tank as it is full. rear tank working and gauge seems to be working off that tank only. Front tank stays full and seems not to be usable. Could it be a sensor maybe?
 
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