* Oxygen Sensor Issues: These sensors monitor the exhaust gases and are crucial for fuel efficiency and emissions. A failing oxygen sensor is a very common cause of a check engine light.
* Mass Airflow Sensor (MAF) Problems: The MAF sensor measures the amount of air entering the engine. A dirty or faulty sensor can lead to incorrect fuel mixture calculations, triggering the light.
* Catalytic Converter Failure: A failing catalytic converter reduces the efficiency of the exhaust system, leading to emissions problems and triggering the light. This is a more expensive repair.
* Ignition System Malfunctions: Problems with spark plugs, ignition wires, distributor cap, or rotor can cause misfires, resulting in the check engine light illuminating.
* Sensor Failures (Various): Many other sensors throughout the engine and emissions system can fail, including temperature sensors, crankshaft position sensors, etc. Each sensor plays a vital role, and a malfunction can trigger the light.
* Evaporative Emission System (EVAP) Leaks: Leaks in the system that handles fuel vapors can also cause the check engine light to come on.
* Throttle Position Sensor (TPS) Issues: A faulty TPS can cause problems with engine performance and fuel delivery.
* Low Coolant Level: While not always directly linked to the OBD system, a low coolant level can sometimes trigger a related code and illuminate the light.
* Loose Gas Cap: A surprisingly common cause, a loose or damaged gas cap can cause small leaks in the EVAP system.
To find the *exact* cause:
You'll need to have the diagnostic trouble codes (DTCs) retrieved from the car's onboard computer. This can be done in a few ways:
* OBD-I Scanner: A scanner specific to OBD-I (the system used in 1994 vehicles) is needed. These are readily available online or at auto parts stores.
* Auto Parts Store: Most auto parts stores will scan your car's system for free and provide the trouble codes. They can then help you interpret the codes and suggest potential repairs.
* Mechanic: A qualified mechanic can diagnose the problem accurately and perform the necessary repairs.
Ignoring the check engine light can lead to further damage and potentially more expensive repairs down the road. It's always best to address the issue promptly.
