The start-stop system is now becoming standard for all vehicles. It turns out that we burn quite a lot of fuel when standing at traffic lights and in traffic jams. The engine idles in such situations and we just lose our money. So, car manufacturers add start-stop systems or automatic engine shut-off systems to almost all new models.
But why can the start-stop system not be working in your Jeep?
In short, the start-stop in your Jeep may fail because of low battery, unacceptable conditions, engine problems, or because you turned off the start-stop function. Also, Jeep has several sensors that are connected with the start-stop system and they can prevent it from working properly if these sensors fail somehow.
In this article, I will investigate the work of the start-stop function in Jeep models and will show you how to find the actual problem.
How should start-stop work in your Jeep?
There are two types of start-stop systems in Jeep vehicles. The first type can be deactivated by pressing a button (A OFF in a circled arrow). The second type doesn’t allow you to deactivate the function that easily. You can still deactivate it by programming the vehicle in the dealership.
Both types work more or less the same. They will stop the engine in the vehicle when it stops and stands for more than 5 seconds. Then, once you release the brake pedal, the engine will quickly start and you will be ready to drive further.
Also, the start-stop system may rely on mild-hybrid technology or on the AGM battery without any hybrid motor and second battery pack.
This is made to economize some fuel and to reduce the ecological impact of your vehicle. Actually, the function may improve your gas mileage in the city by up to 10%. It’s useless on highways, though.
But in many Jeep cars, drivers notice that the start-stop function doesn’t work as it should. The vehicle may or may not show you some messages like “Start-Stop Unavailable, Service Start-Stop System” and the warning light showing the letter A in a circled arrow.
Why can the start-stop function fail in the Jeep?
It’s not normal when some functions don’t work in your car. Even if you don’t use a certain function often, it should be working well. Everything is connected in a modern car, so a little problem may be the sign of a big issue that should be addressed immediately.
Here are the possible reasons why start-stop isn’t working in your Jeep:
1. You turned it off manually
If you press the “A OFF” button, you will turn the start-stop system off. To turn it back on, you will need to press the button again. This is one of the most common reasons why your Jeep stopped turning off the engine at traffic lights and when you park it. Maybe you even pressed the button unintentionally.
So, the first thing to try is to press the “A OFF” button once again and see if the problem is solved. If not, press it once more and make sure that the dash tells you that the start-stop system is now activated. After that, you can move on to look for the problem.
2. The battery is low
In non-hybrid start-stop Jeep vehicles, 12V AGM batteries are used. These batteries are good for start-stop systems because they can be discharged partially and then charged a lot of times without losing their quality. If you use a simple car battery in a start-stop car, this battery will be dead in just several weeks of driving.
But even the AGM battery is not eternal. It may die after 2-4 years of use or even earlier if you drive only in the city with a lot of stop-and-start cycles. The battery will inevitably go low and when this is registered by the ECU, it will turn off the start-stop function automatically.
Usually, when this happens, you will also see the error message telling you that your should service the start-stop system. But sometimes, your Jeep may just deactivate the function without telling you anything like that.
3. The temperature outside is too high or too low
It’s easy – your climate system needs electricity to properly work. If your AC is turned on to max level and the fans are blowing as crazy, the vehicle won’t use start-stop. Once the engine shuts off, the alternator stops working and the AC needs to take the charge from the battery. This way, your 12-volt battery will die in a couple of days. So, when your AC or heater is working and the difference between inside and outside temperatures is big enough, the start-stop system will not be activated.
4. Engine is not warmed up
Your Jeep may not allow you to enjoy all the features of the start-stop system just because the engine is still cold. Once the engine is warmed up to its normal working temperature, the system will start working again.
This is not a problem of failure, this is just how the system works. Until your engine gets the working temperature, the start-stop system won’t shut off the engine automatically. It will let the engine warm up even if it idles at the traffic light.
5. Some door is open
When a door or hood is open, the start-stop system is not working. I don’t know why this happens, but this is kind of the industry standard for the system. Automatic engine shut-off is impossible when one of the sensors in your doors or in the hood is malfunctioning. If it fails, it will send incorrect readings to the ECU and the ECU will block the start-stop system from doing its job.
6. The car is on the hill
One more possible condition when the start-stop is not working is driving on the hill. All vehicles with the start-stop function use hill sensors and when your car is at the traffic light on the hill, the system will not shut off the engine. This is one of the safety measures that help you start driving immediately.
Also, when one of the sensors that check if the car is on the hill fails, this can lead to issues like bad and random work of the start-stop system.
7. Some sensor is malfunctioning
I’ve mentioned the hill sensors and also the door sensors. But there are other types of equipment that may stop your start-stop system from working properly. For example, the engine sensor, speed sensors on your wheels, your ABS, outside temp sensor, etc.
Almost anything can affect the work of the start-stop system in the Jeep and you may not even locate the problem using some scanner. Also, you may not see any other symptoms but the malfunctioning start-stop. If this is the case, you should look for help from professionals.
What to do if the start-stop glitching in my Jeep?
It’s not uncommon that in some Jeep vehicles, the start-stop system may be glitching heavily. It means that the system is not working properly, and there are problems with sensor readings or software.
Here are the steps you can make to solve the problem:
- The most natural step is to just deactivate the system. It won’t shut off the engine automatically and you will spend 10 grams of fuel more each day but it will save you from stalling at the traffic light or finding out that the engine shut off in the middle of the road when you are driving.
- Also, you can choose to go to professionals and have the vehicle diagnosed properly. This will help you find the malfunctioning unit and repair or replace it. Unfortunately, this can be pretty expensive at times.
If you can’t deactivate the start-stop system because there is no “A OFF” button in your Jeep, you should visit the dealership or a trusted repair shop and ask them to reprogram the system. This will obviously help you get rid of all the problems and keep driving the Jeep with pleasure.
Why is start-stop still important?
Most Jeep drivers still use the start-stop system just because they have it in their vehicles. But depending on your driving style, you may not be getting a lot of benefits from the technology.
For example, in vehicles that usually go off-roading or spend most of their time on highways, using start-stop is not efficient. It will not save fuel but will add some risks of glitches that may suddenly shut off the engine in the vehicle.
If you drive most of the time in city traffic, the start-stop system is important. It will help you save some fuel and also reduce the emissions that your car throws into the atmosphere. So, you better keep the system activated at all times.
Final thoughts
If the start-stop system is malfunctioning in your Jeep, you better address the problem immediately. One simple step you can do is to deactivate the system and make sure that all other engine-related systems and technologies work well.
If you still want to use the function of automatic engine shut off, you should go to professionals, have the vehicle inspected thoroughly, and then pay for the repair. Most likely, this is not a serious problem.
Also, check the list of possible natural reasons why the start-stop system may not shut off the engine that’s given above, and maybe you will find the answers to your questions.