WHAT'S THE 'A' BUTTON WITH A CIRCLE AROUND IT IN MY CAR?

Here at CarBuzz, we always find ourselves talking about the advanced technologies found on the modern vehicle. Whether it's designed to improve safety, increase power, improve efficiency, or reduce emissions, the technological advancements made in vehicles are truly impressive.

One advancement that has been made seems to take everyone by surprise, especially if the vehicle owner is unaware their vehicle is equipped with this feature. We're referring specifically to the automatic start-stop system found in many new vehicles. This system improves efficiency by automatically turning the engine off and quickly restarting it to avoid wasting fuel at idle, especially if you find yourself sitting in traffic for hours. If your car has a button marked with an 'A' and a circle around it, it's equipped with an automatic start-stop system.

Automatic Stop-Start Systems Explained

The automatic stop-start system found on many vehicles today is designed to turn the engine off when the vehicle comes to a stop, then it quickly restarts the engine at the press of the accelerator or the release of the brake pedal. The system gained popularity in Europe and has become commonplace in the United States since around 2017. The system does not require additional parts. However, a deep-cycle battery or EFB battery is needed along with a heavy-duty starter, since the vehicle will be switched off and started a lot more often. The engine starter found in an auto stop-start system is typically rated for 30,000 starts.

The First Auto Start-Stop System

Like most technology, the automatic start-stop system was well ahead of its time. The Toyota Crown from the 1970s had the first system. Although it functioned well, the battery technology and engine control systems were not as refined, causing many to forget about it. The system later regained popularity for European automakers such as BMW and Mercedes-Benz.

Earlier start-stop systems were effective at saving gas but were not always refined. Often, drivers experienced an annoying jolt each time the car was switched back on, which can be many times in a single minute in traffic. Today, many modern vehicles with mild-hybrid systems have far smoother start-stop systems.

What Does The 'A' Button With A Circle Around it Mean?

Vehicles equipped with an automatic stop-start system can usually be identified by having a button with the letter 'A' and a circle around it. This button allows the driver to turn off the automatic stop-start system, giving the operator complete control of the system.

When Does The Auto Stop-Start System Not Operate?

When you first start your vehicle, it must complete its warm-up cycle before the system operates. This allows the engine to reach the optimal temperature along with the vehicle's oxygen sensors and catalytic converter. Once the vehicle has reached the operating temperature range, the system will begin to function. The system will NOT operate in the following scenarios.

The Start-Stop Button Is Pressed

The most common way the system will not operate is to simply press the button. Pressing the auto stop-start button will turn the system off, preventing it from operating. In some vehicles, drivers will need to press this button each time the car is first started to deactivate the system.

Engine Faults Or Error Codes

If the engine is suffering from an engine fault and a diagnostic trouble code is active, it's not uncommon for the system to disable itself. A faulty engine temperature sensor or thermostat can also result in the system disabling itself.

4x4 Lo Enabled

If your vehicle is 4x4 and the low-range function is enabled, the stop-start system will not operate. This is to prevent disrupting low-speed off-roading.

Low Battery Voltage

If the battery voltage is low, the stop-start system will not operate in an attempt to preserve the battery charge.

Temperature Fluctuations

If the outside ambient temperature, cabin temperature, or engine temperature are not within the desired range, the system will not function.

Automated Parking

If the vehicle is performing an automated parking maneuver, the system will be temporarily disabled until the vehicle is parked.

Gear Selection

If the vehicle is not in a forward gear range, the system will not operate.

When To Turn Off The Stop-Start System

Most people believe the only reason to turn the system off is when they are annoyed by the engine restarting. This tends to annoy people during traffic most. However, there are other reasons you may want to consider these when deciding to turn off the system:

• Reduce the strain on the battery
• Reduce the amount of restart counts on the starter
• To prevent the A/C from turning off

How Much Fuel Does Auto Stop-Start Save?

The automatic stop-start system was designed to avoid wasting fuel as an engine idles. By burning less fuel, fewer combustion gases are created, thus reducing pollutants from entering the atmosphere. Many people question how much fuel the stop-start systems truly save, and whether the sometimes annoying restarting of the engine is worth it. The early versions were believed to save 3% to 10% of fuel. However, the stop-start systems found on today's efficient engines are expected to improve fuel economy anywhere from 7.27% to 26.4%, according to the Society of Automotive Engineers. According to Natural Resources Canada, fuel consumption was reduced between 4% and 10% on vehicles equipped with stop-start technology.

Sources: SAE, Natural-Resources Canada, Ford, Toyota

2024-09-19T06:53:21Z dg43tfdfdgfd