To find out *why* your SES light is on, you need to get the trouble codes read. There are several ways to do this:
* OBD-II Scanner: This is the most reliable method. An OBD-II scanner (available at auto parts stores or online) plugs into your car's diagnostic port (usually under the dashboard) and reads the diagnostic trouble codes (DTCs). These codes provide clues to the specific problem.
* Auto Parts Store: Many auto parts stores will read the codes for free. They can then help you interpret the codes and suggest potential solutions.
* Mechanic: A qualified mechanic can diagnose the problem and make the necessary repairs. This is often the best option, especially if you're not comfortable working on your car yourself.
Possible Common Causes (but not exhaustive):
Without knowing the specific trouble codes, it's impossible to say for certain what's wrong. However, some common causes for a SES light in a 96 DeVille include:
* Oxygen Sensor (O2 Sensor) Issues: These sensors monitor the exhaust gases and are crucial for proper engine operation. A faulty sensor can cause poor fuel economy, rough idling, and trigger the SES light.
* Mass Airflow Sensor (MAF Sensor) Problems: The MAF sensor measures the amount of air entering the engine. A malfunctioning sensor can lead to poor performance and the SES light.
* Catalytic Converter Issues: A failing catalytic converter can cause a variety of problems, including reduced engine performance and the SES light.
* Ignition System Problems: Issues with spark plugs, ignition wires, or the distributor can trigger the light.
* Evaporative Emission System (EVAP) Leaks: Leaks in the system that controls fuel vapors can cause the light to illuminate.
* Throttle Position Sensor (TPS) Issues: The TPS tells the computer the throttle position. A bad one can lead to drivability problems.
* Low Coolant Level: While seemingly unrelated, a low coolant level can sometimes trigger the SES light due to the engine's temperature.
In short: Don't ignore the SES light. Get the codes read as soon as possible to diagnose the problem and prevent further damage or costly repairs.
