That symbol is your car's auto start-stop system indicator. When this light—an "A" inside a circle, often with the word "OFF" or an arrow circling it—is illuminated on your dashboard, it means the system that automatically shuts off your engine at a full stop to save fuel is currently deactivated. The system is designed to reduce emissions and improve gas mileage, particularly in city driving with frequent stops.
The system activates automatically when you start your car. When you come to a complete stop (like at a traffic light), the engine will temporarily shut off. The moment you release the brake pedal, the engine restarts instantly. A dashboard light will typically illuminate to let you know the engine is in its off phase. The button to manually turn the system on or off is usually located on the center console or dashboard. Pressing it will toggle the system and light the "A with a circle" indicator to show it's off.
Many drivers find the engine restart jarring or are concerned about extra wear on the starter and battery. However, these systems are engineered with heavy-duty components to handle the frequent cycles. The fuel savings are real, especially in heavy traffic. The table below summarizes the potential fuel economy improvement based on EPA estimates for a typical midsize sedan.
| Driving Condition | Estimated Fuel Economy Improvement with Auto Start-Stop |
|---|
| City Driving (Heavy Traffic) | 4-7% |
| Combined City/Highway | 3-5% |
| Highway Driving (Minimal Stops) | Less than 1% |
If you dislike the feature, you can press the button to disable it, but it will likely reactivate the next time you start your car. Some higher-end models allow you to change the default setting through the vehicle's infotainment system.
