Engine Related:
* Oxygen Sensor (O2 Sensor): These sensors monitor the exhaust gases and are crucial for proper fuel mixture. A faulty sensor leads to poor fuel economy, rough running, and will trigger the light.
* Mass Airflow Sensor (MAF Sensor): This sensor measures the amount of air entering the engine. A dirty or faulty MAF sensor can cause a lean or rich fuel mixture, leading to performance issues and the check engine light.
* Catalytic Converter: A failing catalytic converter can cause reduced engine performance and trigger the light. This is often expensive to repair.
* Spark Plugs and Wires: Worn or damaged spark plugs and ignition wires can misfire, leading to the check engine light.
* PCV Valve (Positive Crankcase Ventilation): A malfunctioning PCV valve can cause excessive pressure buildup in the crankcase, potentially damaging the engine and triggering the light.
* Throttle Position Sensor (TPS): This sensor tells the computer the throttle's position. A faulty TPS can lead to poor idle, hesitation, and the check engine light.
* Crankshaft Position Sensor (CKP Sensor): This sensor tells the computer the engine's speed and position. A faulty CKP sensor can prevent the engine from starting or running smoothly.
Emission System Related:
* Evaporative Emission System (EVAP) Leaks: Leaks in the fuel system's vapor recovery system can trigger the light. This often involves checking fuel lines and the gas cap.
Other Potential Causes:
* Loose or disconnected gas cap: Believe it or not, a loose gas cap can cause a check engine light.
* Faulty sensors: Numerous other sensors throughout the engine can contribute.
* Wiring problems: Damaged or corroded wiring can disrupt the engine's electrical system.
How to Diagnose:
1. Get the Diagnostic Trouble Code (DTC): The most important step is to obtain the DTC. You can do this with a relatively inexpensive OBD-II code reader from an auto parts store. The code will give you a much clearer indication of the problem.
2. Consult a Repair Manual: Once you have the code, consult a repair manual specific to your 1999 Dodge Stratus. This will provide detailed information on the possible causes and how to fix the problem.
3. Professional Diagnosis: If you're uncomfortable working on your car yourself, take it to a qualified mechanic for diagnosis and repair.
Ignoring a check engine light can lead to further damage and potentially expensive repairs. It's best to address it promptly.
