Columbia detroit Engine code Sid 55 fault 4

I have a 07 freighliner columbia that has the engine light on. It's showing code sid 55 fault 4. The weird thing about it is that when i am driving and it starts to rain (about 10 min in the rain) the engine light turns off. As long as i am driving on rain or get road the engine light stays off. Aroung 15 min after i start driving on dry roads the Engine light comes back on. I dont know what the problem could be but its got something to do with the water. if i wash the truck the engine light will go off for about an hour and then ill come back on. Any advise on where to start looking THANKS

 

All grounds should be attached to the chassis? Do u know around what area cab to frame ground should be. Thanks