Hybrid electric vehicles rely on two propulsion systems: an internal combustion engine and an electric motor.
Most hybrid vehicles have a high-voltage battery pack and a combination of electric motor and generator to assist the gasoline engine. In some designs, the electric motor can propel the vehicle without starting the internal combustion engine.
As convenient as that sounds, driving a hybrid vehicle isn’t all sunshine and rainbows because it can develop issues like a conventional vehicle.
In the case of a hybrid vehicle, most issues can be traced to the battery packs, which can trigger the hybrid system malfunction warning light.
A hybrid system malfunction means that the vehicle is unable to operate at full capacity because of electrical issues.
A hybrid system malfunction or check hybrid system warning light is usually found in some Toyota and Lexus vehicles with a hybrid powertrain.
This warning light often comes in a yellow or red color. A yellow warning light means that the vehicle is experiencing a minor issue with the hybrid system, while a red one is indicative of a more serious problem.
Several electrical faults can cause the hybrid system warning to pop up, including a blown fuse, defective battery cells, inverter problems, and a worn-out or damaged 12V battery pack.
Defective fuses and exposed wiring can cause a fuse to blow. A blown fuse is indicative of a short circuit, which means that an electrical component can’t handle a strong current.
Each cell is a 2.1-volt battery in itself. A battery cell is made up of positive and negative plates with an insulating separator between them.
Overcharging can boil the cell’s electrolytes and overheating can warp the cell plates. A defective cell can cause the battery’s state of charge to fluctuate, affecting a hybrid vehicle’s performance.
An inverter changes direct current (DC) into alternating current (AC). Most DC-AC inverters have switching transistors that switch on at certain intervals for short pulses.
In a hybrid system, an inverter cooling system is separate from the engine cooling system. The transmission’s inverter side has its own coolant pump, switching valve, and other parts.
Once the inverter fails, the hybrid system malfunction warning light can pop up on the dash accompanied by power loss. Driving with a bad inverter can also damage the battery.
The 12-volt battery pack on a hybrid vehicle powers the electronic control unit (ECU), computer relays, headlights, audio systems, and other accessories, reducing the power that the main battery has to churn out.
If the vehicle isn’t in ready mode, the 12-volt battery disconnects the main battery from the rest of the system. This prevents the main battery from producing a high-voltage output when it’s not needed.
You’ll notice that most of the electrical accessories won’t work once the 12-volt battery pack fails.
A vehicle experiencing a hybrid system malfunction can exhibit the following symptoms:
An illuminated hybrid system malfunction warning light won’t necessarily tell you what the problem is.
Fortunately, the vehicle computer is capable of communicating by storing diagnostic trouble codes (DTCs), informing the driver of what component is causing the problem.
Here are some of the most common DTCs your vehicle could store once the hybrid system malfunction warning light pops up.
Below are some frequently asked questions about hybrid vehicles and system malfunctions.
It’s best to take your vehicle to the nearest auto repair shop as soon as the hybrid system malfunction warning light pops up.
Depending on the severity of the code, there’s a possibility that you won’t be able to drive your vehicle.
Driving your vehicle while the warning light is on display can result in more damage and a more expensive repair bill if left unaddressed.
Depending on the severity of the code, there’s a possibility that you won’t be able to drive your vehicle.
–Anthony Harlin, ASE Certified Master Automobile Technician
Repairing a malfunctioning hybrid system isn’t a DIY-friendly task. Hybrid systems have high-voltage components that can electrocute someone who doesn’t know how to work their way around such vehicles. In most cases, anything in high voltage is wrapped in orange, so take note of that distinction before proceeding with the repairs.
If you’re not an expert on hybrid vehicle repair, it’s best to have a trained professional do the job for you. This will ensure that all steps and protocols for diagnosis and repair are followed correctly.
Most hybrid batteries can last up to 100,000 miles, according to several manufacturers.
Hybrid batteries are more expensive than traditional automotive batteries mainly because they have a longer lifespan than their counterpart.
An illuminated hybrid system malfunction warning light usually points to electrical faults in components like the inverter, battery cells, 12V battery pack, or fuse.
Once the computer detects a fault in the system, you can expect to see a drop in acceleration output and fuel economy.
Make sure to have a professional mechanic take a look at your vehicle before going out for a drive. It’s also not advisable to work on hybrid vehicles on your own if you’re not trained in repairing such systems.
Your hybrid car might run smoothly now, but it’s only a matter of time before your damaged battery changes that. Driving around with a faulty hybrid battery pack affects your car’s acceleration and performance. In some cases, it might even prevent your car from starting. For your own safety, avoid driving until you can replace your defective battery with a new one. Luckily, getting a brand-new hybrid drive battery is fast and easy with CarParts.com.
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Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.