MIL light came on twice NO P codes?

[Frederick]

My MIL ( check engine light ) came on a few weeks ago. This had occured a couple of days after the dealer had replaced the tensioner and pully on my ride. I duly popped the hood and re-seated the air intake system harnesses, this seemed to at the time remedy the MIL light.

However a couple of days ago the MIL light came back on again. This time around fiddling with the harnesses plugs did not remedy the MIL light being on.

The MIL light decided to go off by itself a few days ago. Thus far it is still off. I tried doing the ODO test that pulls the 'P" error codes but nothing showed, E.G. No error codes displayed. I had done this even when the check engine light was still showing.

I was wondering what it could be? Also, would the dealer be able to pull the error code with their tools from the Nitro? Meaning would it store the occurance of the MIL light being activated a couple times in the past with the aim of knowing what triggered it?

Thanks.