got a little freaked out

I don't know if this has happened to anyone else.
I installed a trailer hitch last weekend and I never
Washed the 6 beforehand so it was unbelievable filthy!
So this past Friday I cleaned her up good and sprayed the heck out of the back end!
Up under fender any where I could point the hose!
Well I had a appointment Saturday morning so I was off to the appointment which I was running late for
And I was towing my friends cargo trailer that I borrowed. Well 10 miles from the house the mil came on.
Also know as Check engine light I was panicking that I had a pinched wire but not wanting to be late I proceeded trying to convince myself that I just got something wet.
Well I am almost positive that that's what happened I just got back from a 350 mile ride and everything was ok.