Common Causes:
* Loose or Damaged Gas Cap: This is the most frequent cause of a consistently illuminated SES light. A loose or faulty gas cap allows fuel vapors to escape, triggering the light. Try tightening it first.
* Oxygen Sensor (O2 Sensor): These sensors measure the oxygen in the exhaust. A failing O2 sensor can cause inaccurate fuel mixtures, leading to poor performance and the SES light.
* Mass Airflow Sensor (MAF Sensor): This sensor measures the amount of air entering the engine. A dirty or malfunctioning MAF sensor can cause a rich or lean fuel mixture, triggering the light.
* Catalytic Converter: A failing catalytic converter can cause backpressure in the exhaust system and trigger the SES light. This is usually accompanied by reduced performance.
* Spark Plugs or Ignition Wires: Worn or faulty spark plugs or ignition wires can cause misfires, leading to the SES light.
* PCV Valve (Positive Crankcase Ventilation): A clogged PCV valve can cause excessive pressure in the crankcase, affecting engine performance and triggering the light.
* Throttle Position Sensor (TPS): This sensor tells the computer the position of the throttle. A faulty TPS can cause poor drivability and the SES light.
* Crankshaft Position Sensor (CKP Sensor): This sensor tells the computer the position of the crankshaft. A faulty CKP sensor can prevent the engine from starting or running smoothly.
Less Common, but Still Possible Causes:
* Faulty sensors (various): Many other sensors can trigger the SES light, including temperature sensors, coolant temperature sensors, etc.
* Vacuum leaks: Leaks in the vacuum system can affect engine performance and trigger the light.
* Wiring problems: Damaged or corroded wiring can disrupt the signals to the computer, causing the light to illuminate.
* Faulty engine control module (ECM): While less common, a problem with the computer itself can cause the light to stay on.
How to Diagnose:
1. Check the Gas Cap: This is the easiest and cheapest thing to check first.
2. Obtain Diagnostic Trouble Codes (DTCs): You can use an OBD-II scanner (available at most auto parts stores) to read the DTCs stored in your car's computer. These codes will give you a much better idea of the specific problem.
3. Consult a Repair Manual: A repair manual specific to your 1999 Oldsmobile Intrigue will provide detailed information on diagnosing and fixing potential issues.
4. Take it to a Mechanic: If you're not comfortable working on your car yourself, take it to a qualified mechanic for diagnosis and repair. They have the tools and expertise to accurately pinpoint the problem and fix it efficiently.
Ignoring the SES light is not recommended. Driving with a persistent problem can lead to further damage and potentially dangerous situations.
