"A" with Arrow Around It on the Dashboard – What's This?

Whenever some unknown warning lights come on the dashboard, it can be quite distracting. You may even need to stop the vehicle and google the warning light to make sure that everything is OK with your car and you may keep on driving safely. And this is a really good idea - driving with the unknown warning light flashing on the dash is not the best choice!

A with arrow light highlights

• Common reasons:issues with start-stop system, start-stop can't activate
• How to fix:drive further, check 12V battery, read the codes
• Possible consequences:start-stop won't work, battery may die
• Priority level:Medium
• Can you drive?Yes
• DIY repair:Possible
• Repair price range:$0-$550

Start-stop warning light - explanations

If you see an "A" with an arrow around it on the dash, it means that the start-stop system is giving you some information about the start-stop system. In most cases, vehicles won't have a special light on the dash to signal about the activation or deactivation of the system. But if the light is green or blue, most likely, your vehicle has this feature. It just signals that the system is active and ready to work.

If the light is amber or red, it always means that something is wrong with the start-stop system. In this case, you should pay attention to the symptoms and avoid ignoring this light because it can lead to unpredictable consequences. Usually, the start-stop system is not just malfunctioning on its own, it's failing when something is wrong with other systems and units.

Here are some reasons for this warning light to come on the dash:

• the start-stop system was cut off because of some problem with the starter motor or other equipment;
• the system can't function because of the problems with the 12V battery which is too low or dying;
• you deactivated the system and the vehicle now shows the amber light informing you that start-stop is not working;
• the system was deactivated by the ECU because of other technical problems or limp mode;
• some sensors that are necessary for the proper work of the start-stop system are not working properly, so the system was shut down.

Hundreds of units and modules influence the work of the state-stop system, so you can never know if the issue is actually caused by the battery or by some unknown sensor. To understand this, you will need to provide your car with a proper inspection.

If the start-stop system is not activated due to a low battery, it doesn't mean that there is a huge problem with electric power in the system. The ECU just considers it dangerous for the battery to keep stopping the engine at every corner and then starting it again. After you drive for an hour or two without shutting off the engine, the start-stop system may be activated again.

How does the start-stop system work in your car?

There are several types of start-stop systems. While the cheapest one uses AGM or EFB batteries and a simple starter motor, some newer systems apply hybrid technologies, motor-generators, separate battery packs, etc.

But this doesn't change the pattern of work. Here's how the healthy start-stop system should function:

• once you stop at the traffic light for more than 1-2 seconds, the vehicle shuts down the engine;
• this helps the car avoid burning fuel when it is not needed, so the emissions are zero at such moments;
• once you release the brake pedal, the car starts and is ready to go without you doing anything else;
• the start-stop system may or may not be fitted with the activation button on the central console in your car;
• the start-stop may also work in alliance with other units and functions in your vehicle.

Actually, in many cars, this system is quite annoying. It was introduced to fit the vehicles into the new ecology rules and limitations but not for comfort and fuel economy. That's why the system feels quite raw and throws a lot of unwanted problems like warning messages, unpleasant warning lights, problems with standard operations, and malfunctions that need proper investigation and repair in the dealership.

Of course, there are still some advantages to using this system in your vehicle:

• you make a certain impact on ecology when you avoid idling your engine when it's not needed;
• the gas mileage is actually better with the start-stop system activated;
• at every traffic light, you remember that your car is a high-tech vehicle and has a lot of wonderful features in it.

Well, the last advantage is quite weird but that's what I heard from some drivers when I asked them if they were using the start-stop system in their vehicles. They answered: I don't need to economize those drops of fuel but I want to use this high-tech feature that I paid for in the dealership when buying the vehicle.

Why can the start-stop system malfunction and throw the light?

So, the "A" with an arrow around it in amber or red light will mean that there is a problem with your start-stop system. In many vehicles, there is no special light for this, but the start-stop button starts flashing. This is insanely distractive, so you will certainly want to deal with the problem as soon as possible.

Here are the most common reasons why the start-stop system may malfunction:

1. The 12V battery is dead or dying

If the battery is dying, its voltage will be quite low when under the load. The ECU reads this situation easily and at the next traffic light says that it won't activate the start-stop system anymore. It will tell you this by flashing or just lighting up the warning light.

The only possible way to solve this is to replace the battery with the new one. If the battery is younger than 4 years, you may also try charging it. But remember that AGM or EFB batteries need only a proper charger that is designed for them and utilizes the needed charging pattern.

2. The hybrid battery is dying

In more expensive vehicles, the start-stop system will be powered by a hybrid battery. This is the small battery that powers the mild-hybrid system and is basically made for start-stop and extra torque boost.

The system is pretty durable and won't malfunction at every corner. But sometimes, it can still throw a surprise or two. If this battery needs replacement, you are in trouble because it costs quite a lot.

3. Sensors are broken or crazy

The start-stop system relies on several sensors that tell it when the car is stopped and when it should be activated. Unfortunately, sensors are not really eternal and they sometimes may require replacement.

For example, some sensors may be sending the information to the ECU that one of the wheels is still spinning. This will prevent the start-stop system from activating because it can do the job only when all four wheels are stopped.

4. ECU problem

Sometimes, the ECU will block the start-stop system from activating. For example, when there was a problem with starting the engine recently, the ECU may shut down the start-stop system so that you weren't caught by this in the middle of the road. Also, the warning light may go on to let you know that something is wrong with the vehicle.

Can you just deactivate the start-stop system?

One of the natural solutions when you see the warning light showing the start-stop system problems is to deactivate the system. But while in some cars it's easily done by pressing the "A with an arrow" button, some other cars just don't have this button.

In several modern models, you can't deactivate the start-stop system because it comes as an essential part of the ecology equipment and shouldn't be deactivated manually.

So, if your vehicle has the "A with the arrow" button, just press it to deactivate and then activate the system. If there is no such button, you can deactivate the system with the help of the scanner. In some cars, deactivation is also possible with the help of settings in your infotainment.

Final thoughts

It's always your choice whether you want or don't want to use the start-stop function. But if you see the warning light on the dash, you should be careful: something is wrong. In most cases, this is the problem with the battery. But sometimes, the issue may also be with the sensors, actuators, and other equipment that takes part, directly or indirectly, in the work of the start-stop system.

Don't ignore this warning light and always have your vehicle inspected and repaired once something is wrong with the start-stop feature. It may also show potential problems with other units.