Medium and Heavy Trucks
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Hi my name is***** will be glad to help. What year truck and what are you having for problems with your fuel tank? What are you getting for body controller codes?
Thanks for the info. 612 14 is for HVAC so it is unrelated but there should be more numbers with the 639 14 code which may be related. Let me know. Most commonly with these it is the fuel tank level sensor that fails to signal the pump
Check your fuses and your transfer pump relay. Also test for power to the transfer pump. Let me know
Thank you for the info... The ESC controls the circuit when it recieves signal from the fuel level sensors to command the pump on. Check the sensors and harness at the tank. Also, see if there are more numbers with your fault codes.
there are numbers missing from your codes to identify the circuit. the 612 14 could be these but wed need the rest of the numbers.
612-14p-23-2:short or open on storage tank fuel level sensor circuit
612-14p-25-2:short or open on draw tank fuel level sensor circuit
How much fuel is in each of the tanks? The body controller needs to see around a 20% difference between tanks fuel level before it will turn the pump on through the relay. To test. Check the levels and if they are close move the fuel from the draw tank to the storage as much as possible and then check to see if the ESC signals the pump on after about 5 minutes of running
i am surprised your display is not showing the full fault codes which makes it a bit more difficult to if it is a sensor fault and if so which sensor, etc. We need the full codes to prevent from having to guess. It is likely a sensor problem if the pump is not getting power from the relay and ESC.
Hi, Did you get this resolved?
Click on these links for some diagrams that should help in testing the circuits
Sorry about that.... Here is section 9.9 you need