My CEL stayed on yesterday morning after starting. Checked on this website for the on/off key 3 times, tried it yesterday afternoon with NO results. Nothing, nada, the odometer just kept showing the mileage, no codes. What gives? Thanks.

 

On these suddenly cool nights my truck will do the same. I open the garage and the truck sensor picks up a temperature fluxuation when starting. Seems to do it more in the spring & fall when temperatures are around freezing. My garage is insulated which gives it a bigger temperature difference.

It will probably disappear in a few days. That ding when you first start is a little annoying.