"Check Hybrid System" Toyota Highlander – What Does This Mean?

The Toyota Highlander Hybrid is a practical, comfortable, and stylish mid-size SUV built to be the perfect family vehicle. The Highlander Hybrid features a hybrid system comprised of a 2.5-liter four-cylinder paired with two electric motors.

Check hybrid system message highlights

• Common reasons:12V battery low, connection problems, hybrid battery dying
• How to fix:check the 12V battery, take it in for inspection
• Possible consequences:the vehicle may refuse to start
• Priority level:High
• Can you drive?Yes
• DIY repair:Impossible
• Repair price range:$200-$750

What Does The "Check Hybrid System" In A Toyota Highlander Mean?

Whenever you see the "Check Hybrid System" pop up in your Toyota Highlander, it usually means that your computer system has flagged a problem with your hybrid system. The warning usually shows up in a red triangle.

While the problem may be minor and only require a simple hack to fix, this warning could also mean that the hybrid system in your vehicle could be drawing its final breath. Either way, this issue requires immediate diagnosis and repair in case there is a problem. It is dangerous to drive with this warning because you do not know when the vehicle will break down.

Symptoms of a Failing Hybrid System in Toyota Highlander

It is likely that even before this warning light shows up, you will already be experiencing some symptoms. This is because the light only comes to notify you of something fishy under the hood. Have you noticed one or some of these symptoms?

• Reduced MPG

If there's a problem in your hybrid system, it is likely that the battery won't charge well or won't charge at all. If your first reason for buying the Highlander Hybrid were to save on fuel, you would definitely notice when that goal isn't being met. A few other factors, such as cold weather and improper tire pressure, can cause reduced mileage to the gallon, but if the problem persists, it is your hybrid system you should check.

If you find yourself frequenting the gas station more often than you should, it is because your electric motor isn't assisting the internal combustion engine as often as it should. As a result, the gas mileage per gallon will significantly reduce. There are two explanations for this issue; either the battery isn't charging to its full capacity, or drains quickly.

• Fluctuating State of Charge

Your Highlander Hybrid computer system shows the battery's state of charge on the driver information display. Have you noticed fluctuations in the state of charge that you should be concerned about? You can notice this while driving. If you have, that's a warning of a problem in the hybrid system. The fault could be with the battery or the charging system. Either way, it is a problem with the hybrid system that needs a quick diagnosis and fix.

• Unusual Noises

If there are strange noises originating from the engine bay, it is a sign that something is overworking - either the battery or the internal combustion engine. If the hybrid system fails, the I.C.E will have to kick in more often than usual, which means it'll be overworking.

The unusual noises could also be caused by a constantly running fan, which means the engine or the battery pack is overheating. Too much heat is bad for the battery and surrounding components. You need to get this checked by your nearest Toyota hybrid expert.  

Why Does the "Check Hybrid System" Show Up?

The warning systems in hybrid vehicles are more complicated than in typical vehicles. For instance, the "check hybrid system" warning light can illuminate for several reasons. However, since the hybrid system is quite complex, you cannot determine the problem just by popping the hood. You will need the right tools to scan your system and determine what caused the warning.

Although with the right tools, you can scan at home, you should visit a professional Toyota hybrid specialist to have the system fully diagnosed and fixed. Once the scanning is done, one of these faults will likely be the cause.

• Faulty Battery Cell / Cells

Your hybrid SUV depends on the internal combustion engine and electric motors to increase gas mileage. If one of these fails, the one left alive will be overworked. And the one that is most likely to fail is the battery unit.

If the "check hybrid system" warning comes up, followed by fluctuating state of charge, the culprit is faulty battery cells or just one cell. The symptom will be that your state of charge may jump from zero to fully charged or vice versa. This means the battery has a faulty cell or cells in one of its modules.

• Blown Fuse

The hybrid system in your outlander uses fuses for connections. If one blows, the battery will most likely stop working. A bad fuse in the hybrid system means your vehicle will run solely on the internal combustion engine, significantly reducing the gas mileage per gallon. The good news about blown fuses is that once your scanner leads you to it, you can either replace it yourself or visit your local mechanic to do it for you. You don't have to drive to the dealership to fix a faulty fuse.

• Faulty Inverter

An inverter converts direct current energy into alternating current energy in electric systems. If the inverter is not working properly, energy conversion will be affected. As a result, the hybrid system in your Highlander will not work properly. And this will cause the "check hybrid system" warning light to show up. A faulty inverter can cause a partial or total failure of the hybrid system.

The common cause of faulty inverters is too much heat. And as mentioned earlier, one of the symptoms of a failing hybrid system is strange noises which could be caused by the constant running of the fan. Too much heat is caused by a malfunctioning cooling system, an overheating battery, or the engine.

Your Highlander's hybrid cooling system must be kept cool to ensure it functions to its required capacity.

• The 12V Battery Is Dead

At times, the "check hybrid system" warning could be caused by a faulty battery. Have you had trouble starting your vehicle? If yes, then your hybrid system may not have any issues. Instead, make arrangements to replace the 12V battery.

Car battery replacement is a simple task that you can do at home. All you have to do is get the size and description of your battery and buy a replacement. Another sign of a failing 12v battery is when you experience problems with other electronic components such as headlights and radio.

How to Get Rid Of the "Check Hybrid System" Warning Light

In most cases, this warning will pop up in between drives. Sometimes in the middle of nowhere. You can do many things when this happens, but don't panic. The thought of whether to keep driving with the warning light on can be disturbing. However, before you opt for more complex solutions, start by resetting the system.

To reset the hybrid system, you need to find a place to park and kill the engine. Let it be for a few minutes, and restart the vehicle. Allow the computer system to check again. This simple hack mostly removes the problem, and you will not see it again. You can keep on with your journey.

If resetting the system didn't work, you now need to use a scanning tool to determine the root of the problem. As a hybrid vehicle owner, you should always have an OBD II Bluetooth scanner for Toyota hybrids with you. These scanners are available online for as low as $10.

In many cases, it could be a slight error causing the warning light to show up. Instead of spending money and losing your valuable time driving to the dealership for diagnosis, scanning the system by yourself can save you all that. If the scanner leads you to an easy-to-fix problem, go ahead and fix it and move on with your journey. You may, however, need to visit a professional Toyota hybrid specialist in case you do not understand the results of your scanner.

How Long Should You Drive With The Warning Light On?

The first question should be, is it okay to drive with the warning light on? Yes, it is okay, but not advisable. The "check hybrid system" popped up because of a system failure. Driving with the light on could cause more damage to your Toyota Highlander Hybrid.

Conclusion

The "check hybrid system" shows up because there's a system failure in your hybrid vehicle. The problem could be minor or severe, but you won't know that unless you perform a troubleshooting process. Depending on your experience with hybrid vehicles, you can diagnose the problem or take it to a professional Toyota hybrid mechanic.