What is this sensor on Cummins ISX?

that is the cam position sensor, it has a o-ring on it that will leak after miles and age.

 

that isn't the cam sensor bud, that is the pass throught connector for the jake harness, it will no set a fault untill you turn on and try using the jakes if you leave it unplugged, it has a c-clip on the back side that holds it in place, have to pull the valve cover to access it, the o-rings(there are two of them) leak all the time.

 

the cam position sensor is under the jake pass throught connector.

 

you are correct mrdevildog, my apologies, I was trying to multitask again(thats gonna be my newyearsresolution, NOT to do that anymore), and just glanced at the pic.

vadim2200 yes, you must pull the valvecover to access the rear clip to remove it to replace the o-rings.

 

Almost pointless.. even new o-rings will weep in short order.

i say clean it up and spear a little form a gasket around it whilst its in place.

i should do mine but the carefactor is far to low..