1. Oxygen Sensor: One common cause is a faulty or malfunctioning oxygen sensor. The oxygen sensor monitors the oxygen content in the exhaust gas and helps regulate the air-fuel mixture for efficient combustion. A bad oxygen sensor can lead to issues with fuel efficiency and emissions.
2. Mass Air Flow (MAF) Sensor: The MAF sensor measures the amount of air entering the engine. A faulty MAF sensor can cause the engine to run rich or lean, leading to performance problems and emissions issues.
3. Spark Plugs or Ignition System: Issues with the spark plugs, ignition coils, or ignition wires can cause misfires and can trigger the check engine light. Misfires can lead to rough engine idling, reduced acceleration, and decreased fuel efficiency.
4. Catalytic Converter: The catalytic converter is a part of the exhaust system that helps convert harmful pollutants into less damaging gases. If the catalytic converter is faulty, it can cause the check engine light to come on.
5. Vacuum Leaks: Vacuum leaks in the engine's intake system can cause the engine to run poorly and illuminate the check engine light. These leaks can affect air-fuel mixture and overall performance.
6. Evaporative Emission System (EVAP) Problems: Issues with the EVAP system, which is responsible for controlling fuel vapors in the fuel system, can also trigger the check engine light.
In the case of a 1998 Mazda Protege, the actual reason for the check engine light can be determined by connecting a scan tool to the vehicle's diagnostic port to retrieve and decode the trouble code stored in the engine control unit (ECU). Having the trouble code diagnosed by a qualified mechanic or automotive technician is recommended to accurately identify the root cause of the issue.
