i have had my mp-8 on my truck for a couple of weeks now and have no issues, but today i was pulling 38' 5th wheel for the first time and got about 75mi. and the engine light came on and then i noticed the overhead was saying cat full service req. i pulled over un-plugged the mp-8 box then pluged back in and started truck the message on overhead was gone but engine light still on. is this normal?????