Possible causes range from minor to major:
* Loose or damaged gas cap: This is a common and relatively inexpensive fix. A loose or faulty gas cap can allow fuel vapors to escape, triggering the light.
* Oxygen sensor issues: These sensors monitor the air/fuel mixture. A malfunctioning sensor can lead to poor fuel economy and emissions problems.
* Mass airflow sensor (MAF) problems: This sensor measures the amount of air entering the engine. A faulty MAF sensor can cause rough running, poor performance, and the check engine light to illuminate.
* Catalytic converter problems: A failing catalytic converter can be costly to replace.
* Spark plug or ignition coil issues: These can cause misfires, leading to poor performance and the check engine light.
* Problems with the engine control module (ECM): This is the "brain" of the engine. Problems here can be serious and expensive.
* Other sensor failures: Various other sensors monitor engine functions. A failure in any of these can trigger the light.
What you should do:
1. Get the Diagnostic Trouble Code (DTC): This is the key. You can use an OBD-II scanner (available at most auto parts stores) to read the code(s) stored by the vehicle's computer. The code(s) will give you a much better idea of the specific problem.
2. Research the DTC: Once you have the code(s), search online (e.g., using Google) to find out what they mean. Many automotive forums and websites provide explanations of common trouble codes.
3. Consult a mechanic: If you're not comfortable diagnosing and repairing the problem yourself, take your Tahoe to a qualified mechanic. They can diagnose the issue accurately and perform the necessary repairs.
Ignoring the check engine light is not recommended. Driving with a malfunctioning engine can cause further damage and potentially create safety hazards.
