The check engine light could come on in a 2003 Mazda Protege for a variety of reasons. The issues could range from quite minor to very serious. In order to determine the exact issue an OBD-II scanner would be needed to connect to the on-board diagnostic port. This would allow the scanner to communicate with the computer and diagnose the issue. There are sensors scattered throughout the vehicle that all communicate with the computer this includes in the engine when one of these sensors either goes out or detects an abnormal reading this will cause the computer to think there is a problem and will illuminate the check engine light to let You know that there is a problem.
Eric M
July 16, 2020
The check engine light on the 2003 mazda protege is a catch all that is designed to alert you to an issue with the vehicle. It gets turned on when the computer in the vehicle detects an error on the vehicle and stores a trouble code. You can read that code with an obd scanner and this will tell you what the issues is. Common issues can include a loose gas cap, the engine misfiring, d***y spark plugs, vacuum leaks, low oil pressure, and nearly anything else. The light can also come on to remind you to get the vehicle serviced if you are nearing a mile stone. The check engine light is not often a major issue, but it should not be ignored either.
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