The green circle that shows up in BMW models indicates that the Auto Start/Stop function is active. This system automatically turns off the engine when the vehicle comes to a stop, such as at a traffic light, to help maximize fuel efficiency. When the brake pedal is released, the engine automatically restarts.
What does the green circle with an A in it mean in a BMW?
The green circle with an ‘A’ inside it stands for ‘Auto Start/Stop Active’ in BMW vehicles. This light comes on when the Auto Start/Stop function has automatically shut off the engine at idle to conserve fuel. When the brake pedal is released, the engine will automatically restart and the green circle light will turn off.
Why does a green circle come on in my BMW?
The green circle illuminates in BMW models when the Auto Start/Stop function is in operation. This system turns the engine off when the car comes to a complete stop in order to save fuel. It then restarts the engine automatically when the brake is released. The green circle is BMW’s way of indicating that Auto Start/Stop is currently active and has shut off the engine at idle to maximize fuel efficiency.
In what BMW models does the green circle appear?
The green Auto Start/Stop activation circle appears in many modern BMW models including:
- 1 Series
- 2 Series
- 3 Series
- 4 Series
- 5 Series
- 6 Series
- 7 Series
- X1
- X3
- X4
- X5
- X6
- X7
- Z4
So if you’re driving a late model BMW and see a green circle light up on the instrument panel, it means the Auto Start/Stop system has kicked in to shut off the engine at idle in order to conserve fuel.
Where in the BMW is the green circle located?
The green Auto Start/Stop activation circle is located on the instrument cluster, situated to the right of the tachometer on most BMW models. It is clearly visible through the steering wheel so drivers can easily see when the system has automatically shut off the engine at a stop.
Why does my BMW green circle sometimes flash?
If the green Auto Start/Stop circle is flashing in your BMW, it means that certain conditions have prevented the system from shutting off the engine at idle. This can happen if:
- The engine is not up to proper operating temperature
- The battery charge is low
- There is high demand on the climate control system
- Certain safety features are in operation, like the turn signals
Once the inhibiting factor is resolved, the green circle will stop flashing and stay illuminated solid when Auto Start/Stop activates and shuts off the engine at the next stop.
How do I turn off the Auto Start/Stop system in my BMW?
If you want to deactivate the Auto Start/Stop function in your BMW, you can do so by:
- Pressing the Auto Start/Stop button located near the gearshift selector or on the lower dash. This will turn off the system and prevent it from shutting off the engine at stops.
- Putting the car in Sport mode, which automatically disables Auto Start/Stop.
- Switching to Manual transmission mode in automatic transmission vehicles.
When Auto Start/Stop is turned off, the green activation light will not come on when you come to a stop.
Should I disable the Auto Start/Stop system?
BMW recommends leaving Auto Start/Stop enabled for maximum fuel savings, unless you are driving in very hot or cold temperatures. Disabling it will reduce fuel efficiency. However, if you find the automatic shutdowns bothersome, you can turn off the system through the methods above and the green circle will stay off.
Why does my BMW sometimes restart slowly when the green circle is on?
If your BMW seems to restart slowly or weakly when the green Auto Start/Stop circle is illuminated, a few factors could be to blame:
- Low battery – Auto Start/Stop puts extra strain on the battery, so it may need to be tested or replaced.
- Faulty starter – Worn starters can struggle with the extra starts required by Auto Start/Stop.
- Old spark plugs – They may fail to properly ignite combustion on engine restart.
- Low fuel pressure – Weak fuel pump pressure can lead to poor restart performance.
Addressing these common issues can typically restore crisp, quick restarts when your engine automatically turns back on after Auto Start/Stop activation.
How does the Auto Start/Stop system work?
Here is a quick overview of how BMW’s Auto Start/Stop function operates when the green circle is illuminated:
- As you brake to a halt, a variety of sensors detect the stop and immediately switch off fuel delivery and ignition to shut off the engine.
- The brake system remains fully operational through an electric hydraulic pump.
- When you lift off the brake, a high performance starter immediately fires the engine back to life.
- Sophisticated electronics ensure accessories like power steering and climate control are unaffected.
- The entire process occurs in just fractions of a second for seamless stop-start driving.
This sequence maximizes fuel savings while aiming to keep engine restarts imperceptible to the driver. The green circle provides visual confirmation that Auto Start/Stop is functioning.
How much fuel does Auto Start/Stop save?
BMW estimates that their Auto Start/Stop technology improves fuel consumption by up to 5% under normal driving conditions. Savings can be as high as 10% in heavy urban traffic where the system has many opportunities to shut off the engine at stops.
For example, over the course of a year with 12,000 miles of combined city and highway driving, a BMW 328i could save around 40 gallons of fuel using Auto Start/Stop. The more stop-start driving you do, the greater the potential fuel economy benefit.
Auto Start/Stop Estimated Annual Fuel Savings
| Model | City MPG | Highway MPG | Combined MPG | Annual Gallons Saved |
|---|---|---|---|---|
| 328i Sedan | 22 | 34 | 26 | 40 |
| 528i Sedan | 23 | 34 | 27 | 44 |
| 740Li Sedan | 20 | 30 | 23 | 34 |
| X3 xDrive30i | 21 | 29 | 24 | 36 |
Assuming an average gas price of $3 per gallon, Auto Start/Stop could save you over $100 annually in fuel costs depending on your BMW model and driving habits.
Does Auto Start/Stop put more wear on the starter motor?
It’s understandable to be concerned that the increased number of engine starts caused by Auto Start/Stop could wear out your BMW’s starter motor faster. However, BMW uses heavy duty starters designed specifically to handle the extra duty cycle.
Reinforced internals, robust solenoids, and optimized gear reduction provide durability and low-speed strength for rapid and reliable restarting. Testing shows these components last for over 300,000 start cycles in Auto Start/Stop service – equivalent to over 10 years of driving. So while used more often, they are designed to handle the increased workload.
Does the green Auto Start/Stop circle relate to the battery?
The BMW green circle is directly related to battery function. In order for Auto Start/Stop to activate, the car’s battery must have sufficient charge and operating capacity. The system will not switch off the engine at idle if it detects the battery cannot support a quick restart. This helps prevent the frustrating experience of a dead battery at the next traffic light.
BMW batteries used in conjunction with Auto Start/Stop receive extra plates and stronger chemical mixes to withstand the increased energy demands. If you replace your BMW’s battery, make sure it is rated for Auto Start/Stop duty.
Conclusion
In summary, the green circle illumination in late-model BMWs signals that the Auto Start/Stop fuel saving system has kicked in by switching off the engine at idle. This indicator provides confirmation that the technology is functioning to maximize fuel efficiency in your BMW. Understanding when and why it activates can help you get the most from this useful advancement in engine management.