What Does the Check Hybrid System Warning Indicate on Your Toyota?

Vehicles are manufactured with automatic systems that read signals from various parts to diagnose and alert the driver of potential or occurring issues. Different reasons usually trigger these preinstalled warning systems; hence, when you see the warning light, you might not be able to find the cause of the warning lights directly.

What does it mean?

When you see the ‘check hybrid system’ light on your dashboard, this indicates that there is a fault with your car’s hybrid system. This alert only occurs with hybrid cars; hence, you might have experienced this issue before if you drive a hybrid Toyota.

When this light comes on, you might notice other symptoms such as reduced speed, switch to gasoline use, limp mode activated, and poor fuel economy.

Check Hybrid System warning

What can cause this warning?

Hybrid cars use more than one specific power source, such as combining an electric motor with an internal combustion engine. The hybrid system exists to serve as a regulator of the different power sources. There are times when the system is disrupted due to various factors, and the warning light is triggered.

01. Inverter failure

A faulty inverter might trigger the warning light. An inverter that converts DC energy into AC energy must be kept cool to ensure proper function. A lag in the inverter’s efficiency is likely to indicate a faulty hybrid system. Overheating might arise when this happens. The inverter coolant becomes weak and excessive heat is generated.

Most likely, you only need to drain the inverter coolant, flush, and refill. However, on higher mileage vehicles, the inverter itself can fail.

02. Battery cell failure

The battery of the car powers electrical systems. Therefore, if an issue arises with the battery, there is a high likelihood that the systems will malfunction. You might be able to detect a bad battery if your hybrid battery charge fluctuates.

It might fluctuate from full to empty or the other way around. Immediately after this is observed, the battery’s health should be checked because a faulty cell is most likely in one of its modules.

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03. 12v Battery failure

Your car’s 12-volt battery might also trigger the warning lights. The 12-volt battery is the battery pack used in gasoline-powered vehicles and is also present in hybrid cars. If the battery is faulty, it can trigger hybrid-related warnings.

If your 12-volt battery is the cause of the warning light, you might notice other issues like your car’s electrical accessories not starting. It might also cause the warning lights of different electrical systems to come on.

The process is relatively simple if you want to check a 12v battery with a multimeter. You need a digital or analog multimeter that can measure DC voltage.

First, set your multimeter to the DC voltage setting. Then, connect the positive (red) lead of the multimeter to the positive terminal of the battery and the negative (black) lead of the multimeter to the battery’s negative terminal.

If the battery is fully charged, you should see a reading of around 12.6 volts on the multimeter display. If the battery is discharged, you’ll see a lower voltage reading.

04. Blown fuse

The fuse or plug of a hybrid battery is a safety device attached to the battery. Since the hybrid battery is connected to a fuse, the battery will not power the car if the fuse stops working.

Electrical power coming from the hybrid battery must pass through this device before spreading through the car. Fortunately, this can be fixed by replacing the fuse attached to the battery.

Fuses are relatively easy to check and replace, and they are often the cause of most electrical problems. To check a car fuse, all you need is a multimeter.

First, find the fuse box. On Toyota cars, it is usually located under the dashboard, on the left side. For the exact location, you can consult the owner’s manual.

Once you have found the fuse box, open it and use the multimeter to test the fuses. If a fuse is blown, it will show as a break in the continuity. Simply replace the fuse with a new one of the same amperage.

I recommend starting by checking the easy things first, which are the fuse and the 12v battery. If you have an OBD2 scanner, you can hook it to your car and see what error codes you get.

If the fuse and the 12v battery look fine, and you are not reading any error codes, it is perhaps time to have the car diagnosed by a professional.

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How much does it cost to fix the Check Hybrid System Light?

Below I have included a table with the possible causes and how much you will be looking at to fix any of those issues. Keep in mind that prices will vary depending on your location and whether or not you decide to have the car repaired by a dealership, indy, or DIY.

Possible causeRepair cost
Inverter failure$2000-$2500
Inverter coolant, flush, and refill$150
Battery cell failure$2000-$3000
12V Battery failure$150-$250
Blown fuse$10-$20

What should you do when the light comes on?

When the warning light of the hybrid system comes on, the first step is to try to figure out the cause. Next, you might check for other symptoms alongside the warning light coming on because this might give you a clue as to what’s causing the warning to appear.

After figuring out the cause of the warning, you should try to fix it. You could try resetting the system if there’s no traceable cause. If the light still appears after a reset, you should visit the mechanic’s workshop for better examination and repair.

Can you still drive with the Check hybrid system warning?

While the car can still be driven technically, it is not recommended to drive it if the Check Hybrid System warning is on. This might cause further damage to the vehicle’s hybrid system, resulting in a hefty repair bill.

It is recommended that you have the system checked by a qualified technician as soon as possible to ensure optimal performance.

How do you fix a hybrid warning light?

A quick way to fix the hybrid warning light is to reset the system. Once you get the signal, the car should be parked and shut down. After shutting down, you should wait for the vehicle to cool for a while. Then you can restart the car’s computer system.

Once the vehicle is restarted, the light usually doesn’t come back on. This reset method only works for minor electrical issues; hence other issues should be treated according to severity.

As aforementioned, if a faulty fuse is the cause of the problem, a replacement will easily stop the light from appearing. Although a blown fuse might seem to be a minor issue, it should not be treated as such. Why so?

If a fuse stops working when the car is in motion, it might cause an immediate shut down of the hybrid system and crash. Therefore, the fuse should be checked regularly to ensure its good condition.

If the cause of the warning is the 12v battery failure, a replacement might solve the issue. You can easily buy and replace it by looking it up online or checking your car’s service manual.

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Are there any recalls addressing the issue?

A couple of recalls address the issue in Toyota cars, specifically the Part 573 Safety Recall Report 18V-684 and Part 573 Safety Recall Report 20V-369.

Toyota recalls specific Prius and Prius prime cars with hybrid system issues. The ECU software of these cars detects false errors and subsequently shuts down the hybrid system resulting in a loss of power for driving.

This issue is very risky because if power is lost while driving, the risk of a crash is increased. Due to the manufacturer’s fault, drivers who experience this are entitled to free software updates.

Toyota also recalls specific 2012-2015 Prius cars and certain 2014-2017 cars. These cars experience high voltage in the IPM (Intelligent Power Module) in the inverter, which also causes the hybrid system to shut down.

This problem can also cause a crash while driving. Due to this, all repairs relating to this issue will be carried out free of charge by Toyota dealers.

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Closing thoughts

The warning light of a car’s hybrid system is mainly caused by an electrical, battery, or system fault. The light might indicate a minor issue or a critical one. Therefore, when the warning light is observed, this should not be ignored but be treated with utmost speed.

If the problems causing the warning light cannot be fixed at home, you should take the vehicle to the mechanic’s workshop as soon as possible.