Many people freak out behind the wheel if a warning light appears on the dashboard. Some show vital system malfunction, but others are less serious, like the one at hand.
What does it mean when your car orders you to leave the engine running? It can happen when you start the car or are already cruising. Whichever the case, it implies a problem with the battery or the charging system, but other related causes exist.
Let’s dive in for detailed information about the meaning, causes, and how to fix the “stop vehicle leave engine running” warning message.
What Does “Stop Vehicle Leave Engine Running” Warning Mean?
Simply put, the Stop Vehicle Leave Engine Running warning message means a problem with the battery or the charging system. The battery may be low on charge, dead, or not charging.
But if the battery is not charging, the alternator or any charging system component can be the culprit. But before reaching any conclusions, you need to test the battery to ensure it’s not the problem.
The warning message tells you to keep the engine running to allow the battery to charge. Stopping the engine at this time might leave you stranded in the middle of nowhere since it might not crank again.
Low battery power or a faulty charging system is the last thing you might wish for, especially during long rides. Fortunately, you can fix it if you are a DIYer.
Causes of Stop Vehicle Leave Engine Running Warning
The warning message “Stop Vehicle Leave Engine Running” appears on the dashboard due to the following reasons:
The battery is an essential component of any automobile. Its primary function is to provide power to run all electricals and electronics. But most of all, it delivers the electrical power needed to start the engine. Any car with an internal combustion engine requires the battery to crank.
Most cars nowadays have battery power monitoring and management systems. When it detects low battery voltage, it might light up the battery light on the dashboard or trigger a warning message.
The engine won’t start if the battery is dead or damaged. This might trigger the car to display a warning message.
Faulty Auxiliary Battery
Apart from the primary battery, some modern cars have auxiliary batteries. This is necessary to keep some vital electronics and safety systems working in case something happens to the primary battery.
A faulty auxiliary battery might cause some systems, such as GPS, drive assist, and infotainment, to stop working. Also, the two batteries are connected and work together. A problem in one is likely to destabilize the system.
Fortunately, auxiliary batteries have a longer service life. They typically last between 4-6 years. So, if it is that old, it’s most likely the cause of the Stop Vehicle Leave Engine Running warning.
But the auxiliary battery can also be problematic if it’s not the recommended replacement for your car. Some electronic systems and components are sensitive to changes in voltages.
Loose Battery Terminal Connection
This is self-explanatory. Loose or corroded battery terminals and connections might cause intermittent current flow. This tricks the battery monitoring systems and throws all other electricals and electronics off balance.
Radio or Light Not Turned Off
Radios, interior lights, and headlights depend on the battery power if the engine is not running. They drain the battery.
The car will remind you to leave the engine running to keep the battery charged when your stereo system and lights are on.
Parasitic Battery Drain
Parasitic battery drain can be caused by car alarms, tracking systems, short circuits, etc. These can make the battery voltage drop below the recommended minimum.
Short circuits can cause enormous currents to drain from the battery. This will overwork the battery and charging system, tempting your car to throw a warning message.
An alternator does one function; generating electrical power for charging the battery and running electrical systems. It is a vital component of the car battery charging system.
A faulty alternator cannot generate enough power to charge the battery and meet the demand. This will cause the battery voltage to fall below the minimum as more current is drawn from it to run the electrical and electronic systems. The result will be a warning message or a red battery light on the dashboard.
Defective Voltage Regulator
As the name implies, a voltage regulator keeps the voltage from the alternator nearly constant and ensures enough power gets to the battery to charge it.
A faulty voltage regulator may send less power or nothing to the battery. So, your car will tell you to keep the engine running because the battery is not charging. That will be the case if you get a warning light when driving.
Too Many Electronic Consumers Connected
Your car battery has rated power it can supply. This means it can support a specific number of electrical and electronics at the same time.
Having many accessories turned on draws more power from the battery than it was designed to handle. As a result, the car will think the battery is not charging when the voltage drops and throw the warning message on the dashboard.
How to Fix Stop Vehicle Leave Engine Running Warning
What to do when a “stop vehicle leave engine running” warning appears? The first step is not to turn off the engine, as directed by the vehicle. Ensure you are at an auto repair shop or your garage before you can turn off the ignition.
You should only stop the engine when it is safe and ready to diagnose it. Once you are in your garage, you can troubleshoot it by doing the following:
- Switch off all the accessories, including heated seats, radio, AC, lights, etc.
- Clean battery terminals and ensure no loose connections to the battery
- Let the car idle for about 30 minutes for the car battery to charge
- If the battery does not recharge after 30 minutes, connect a recommended trickle charger to recharge your battery manually.
- If the battery still does not charge, you may need to replace it. It might be dead. But if it recharges externally, the problem is your charging system. Call an expert to help you diagnose it.
How long should you keep the car running after getting the message?
If the message appears because of the low battery voltage, leaving the car running for about 30 minutes should resolve it. But if it is for other reasons, fix it as soon as possible because leaving the engine running won’t help.
How long does a Mercedes-Benz battery last?
Mercedes-Benz batteries typically last 4 years or more if not abused and well maintained. However, this may depend on the battery type.
What does a new replacement battery cost?
The battery cost significantly varies depending on the type and your car model. A low-cost battery for Mercedes-Benz is about $75-$120, but you can get some exceeding $200.
How to know if the car needs a new battery
Most cars will turn on the battery light when the battery is weak. But the surest way is when you need to frequently jumpstart your vehicle. A weak car battery often runs out when left overnight.
What is an auxiliary battery?
An auxiliary battery is a backup battery used in some modern cars to run vital electrical and electronic systems when there is a problem with the primary battery. It is available on some models only.
Do not panic when your car displays the “Stop Vehicle Leave Engine Running” warning message. It simply means the battery is not charging or excess power is being withdrawn from it. Turning off some accessories or leaving the car idle for about 30 minutes should resolve the issue.
But in some cases, you might need to replace the battery or repair any faulty battery charging system component. The worst scenario will be replacing the alternator. Otherwise, you can have your car back on the road the same day.