P0118 engine coolant temp sensor 1 circuit high

[rwatson708]

Having a problem with my truck and it keeps throwing this code. It is intermittent and does it when it wants and runs perfect other times. MY gauge is very intermittent sometimes it works sometime it quits right in the middle of a drive and just pegs to zero. THIS obviously turns and heater fan on and makes the truck sluggish. Any ideas I've changed the ect sensor. IS it a chafed wire? Thermostats? Maybe I got a w sensor that was bad? Bad wire harness for the sensor? CONNECTION pin in the dash? ANY ideas would help. What would happen if I just unhooked the sensor would the fan still kick on?

Newish to the 6.4l so any help would be greatly appreciated before I pay out my ass

Thanks

 

[rwatson708]

Forgot to add I have already changed the sensor once wt no luck

 

[6.0 Tech]

Sounds like wiring.the harness for the ect sensor runs under the intake, its real common for rodents to make that yheir home and startbchewing on chit. Check there. Its in the front by the oil filter housing. The harness runs with the eot and eop switch wiring, but continues down under yhe intake to the front cover where the sensor is.

 

[rwatson708]

What happens if I unplug it temporarily, obviously a dtc but will the fan still kick on and off?

 

[6.0 Tech]

More than likely. The computer will not know what is going on. It will see ect as -40, and eot at whatever it is ~200 so it will turn thebfan on. May also derate and throw the wrench light for oil cooler, but im not 100% on that.