dssur
+1y
pull the bulb.
The "check engine" light on a Mazda truck is just an EGR service reminder, triggered by mileage. There is no OBD (on board diagnostics) that turn the light on for any specific reason except when service of the EGR system is recommended. In fact in early trucks the light is correctly labeled "EGR", they changed it to "check engine" to imply having an OBD system when in fact it doesnt.
And the "service" that is recommended is to have look at the cats. Then a tech reaches under the dash and resets the reminder by moving a jumper from one plug to another.
However yours is not staying on, so I think you have a loose connection somewhere or a bad bulb. Since you dont need the reminder, it will cost less just to pull the bulb.
But you can spend hundreds in diagnostics and replacement parts at the dealer if you want.
I had a nice little blue mazda, and when I put it up for sale I asked a fair price. EVERY SINGLE PERSON that came and looked at it said "I would buy it but the check engine light is on". The ad in the paper expired, no sale. So I pulled the bulb, re ran the ad, and the first caller gave me my asking price.