* Low Fuel Pressure: When the fuel level gets very low, the fuel pump may struggle to draw enough fuel, leading to low fuel pressure. The car's computer detects this and illuminates the check engine light as a warning of a potential problem.
* Fuel Pump Malfunction (worsened by low fuel): Running consistently on low fuel can damage the fuel pump as it's working harder than intended. This damage might only become apparent after the low fuel incident, causing the check engine light to illuminate. The low fuel level stressed the already weakening pump.
* Contaminants in the Fuel System (aggravated by low fuel): Sediment or debris in the fuel tank can be more easily sucked into the fuel system when the fuel level is low. This can clog filters or damage components, triggering the check engine light.
* False Positive: In rare cases, running very low on fuel might cause a temporary glitch in the system that triggers the light. This isn't necessarily a persistent problem.
What to do:
1. Refuel: The most important step is to fill your fuel tank. This addresses the most likely cause (low fuel pressure).
2. Check the Engine Light Code: After refueling, drive the vehicle for a while. If the light remains on, you'll need to get the diagnostic trouble code (DTC) read. You can do this using an OBD-II scanner (available at most auto parts stores) or by taking your vehicle to a mechanic or auto parts store that offers free code reading. The code will provide more specific information about the problem.
3. Address the Underlying Issue: Once you have the code, you can research the cause and potential solutions. If the problem persists after refueling, you likely have a more significant issue (like a fuel pump problem) that needs professional attention.
Don't ignore the check engine light. Continuing to drive with a consistently illuminated check engine light can lead to further damage and costly repairs.
