Hybrid Car Warning Lights Explained (2025)

The “Check Hybrid System” or “Hybrid Battery” light is a particularly dreaded sight for any owner. The good news? You shouldn’t panic. Understanding what these lights mean is the first step to making a smart, cost-effective decision about your vehicle’s health.

Your Car Is Talking to You

Dashboard lights are your vehicle’s way of communicating. A hybrid, with its complex combination of a gasoline engine and electric motors, has a unique set of symbols that are designed to protect both the driver and the car’s intricate systems.

At Greentec Auto Canada, we believe that understanding these warnings is the key to preventing a small problem from becoming a massive expense. Ignoring a warning light is the single most common reason a simple fix turns into a costly repair.

Here is your straightforward guide to the most common hybrid car warning lights for Canadian drivers in 2025. We’ll tell you what each one means, what to do, and why it’s so important not to ignore them.

The Most Feared Light: The Hybrid System Warning

This is the most generic and arguably most confusing light. It can look like a car with an exclamation mark, a triangle with an exclamation mark, or simply say “Check Hybrid System.”

• What it means: This light is your car’s “check engine light” for the entire hybrid powertrain. It doesn’t point to one specific part; it simply says the computer has detected an issue somewhere in the hybrid system.
• What could be wrong:
  • A failing hybrid battery: This is the most common cause, especially in older hybrids. A weak battery forces the gas engine to work harder, triggering the warning.
  • A failing inverter: The inverter converts DC power from the battery into AC power for the electric motor. An inverter malfunction is a serious issue that can also trigger this light.
  • A faulty 12-volt battery: Yes, the small battery that starts your car can be the culprit. A weak 12V battery can cause a cascade of electrical issues that confuse the main computer and trigger the hybrid warning light. 
• What you should do: Don’t ignore it. While a yellow light means you can likely still drive to a service centre, a red light (which may appear alongside it) means you should pull over as soon as it is safe and call for a tow.

The Hybrid Battery Warning Light

This light, which often looks like a battery with a little sun or fan next to it, is more specific than the “Check Hybrid System” light.

• What it means: This indicates a problem with the high-voltage hybrid battery itself. It’s an urgent warning that the battery’s performance or health is outside of the normal operating range.
• What could be wrong:
  • Individual cell failure: A single weak cell in the battery pack can bring down the performance of the entire pack, triggering the light.
  • Overheating: If the battery’s cooling system is clogged or not working properly, the battery can get too hot, which can cause significant, irreversible damage. The car’s computer will trigger the warning to prevent this from happening.
  • Imbalance: Your car’s computer might detect a voltage imbalance across the battery cells, indicating a problem.
• What you should do: Take your car to a hybrid specialist immediately. If you keep driving with this light on, you risk further damaging the battery and other key components, potentially leading to a much more expensive repair down the road. 

The Cooling System Warning

This warning often shows an image of a thermometer in a liquid. While common in standard gasoline cars, it takes on added significance in a hybrid.

• What it means: This light indicates that the engine’s coolant temperature is too high. In some hybrids, a separate light or message will also appear if the hybrid battery’s cooling system is malfunctioning.
• What could be wrong:
  • Low Coolant: A simple but serious issue. A leak in the system or simply not having enough coolant can cause the engine to overheat.
  • Failed Water Pump or Fan: A broken pump or fan can prevent coolant from circulating, leading to dangerously high temperatures.
  • Clogged System: Debris in the radiator or the hoses can restrict coolant flow.
• What you should do: If this light is red, pull over immediately and shut off your car. Continuing to drive can cause irreversible engine damage. If it’s a separate warning for the hybrid battery cooling system, seek professional help as soon as possible to prevent battery overheating.

Common Hybrid Diagnostic Trouble Codes (DTCs) by Model

A warning light is a general signal, but a diagnostic trouble code (DTC) is the key to understanding the specific problem. Here are some of the most common codes our specialists see on Canadian hybrid models.

Code	Common Meaning	Models Affected	What It Means for You
P0A80	Replace Hybrid Battery Pack	Toyota Prius, Toyota RAV4 Hybrid, Honda Civic Hybrid	This is the most infamous code. It means the car’s computer has detected a significant voltage difference in the battery, indicating a failing pack.
P0A93	Inverter Cooling System Performance	Toyota Prius, Ford Fusion Hybrid	This code points to a problem with the inverter’s cooling system. This can be a simple fix like low coolant, or a sign of a more serious issue with the pump or fan.
P3011-P3024	Weak Battery Block	Toyota Prius, Lexus CT 200h	This series of codes means a specific “block” of battery cells is out of balance with the rest of the pack. The last two digits pinpoint the exact block.
P0A7F	Hybrid Battery Pack Deterioration	Honda Civic Hybrid, Toyota Camry Hybrid	This code indicates that the overall resistance in a battery module is too high, a clear sign that the battery is degrading. It’s an early warning that replacement is needed.
C1241	Low 12V Battery Positive Voltage	Toyota Camry Hybrid, Ford Escape Hybrid	This code is often mistaken for a high-voltage hybrid battery issue. It simply means your small 12-volt battery is weak or has a bad connection, which can cause other system warnings to appear.

Important Note: These codes are a starting point. They tell the technician where to look, not exactly what to fix. A professional diagnosis is always required to confirm the issue and ensure the correct part is replaced.

Don’t Guess, Get a Professional Diagnosis

While it can be tempting to use a simple code reader or try a DIY fix, a hybrid vehicle is too complex to leave to chance. As a Canadian forum user on a Prius forum recently warned, “If you get a good scanner you don’t have to guess.” This is the core of the issue. Without the right diagnostic tools and specialized knowledge, you might end up replacing the wrong part, wasting money, and failing to fix the root problem.

At Greentec Auto Canada, our technicians are experts in all things hybrid. We don’t just read the code; we diagnose the entire system to find the real issue. We will tell you if your warning light is caused by a simple sensor fault, a clogged cooling fan, or if it’s truly time for a hybrid battery replacement.

Our goal is to give you a transparent and accurate diagnosis so you can make an informed decision. And if you do need a battery, our affordable, high-quality remanufactured batteries are the perfect solution.Your car is trying to tell you something. Don’t let a warning light become a costly surprise. Contact Greentec Auto Canada today for a professional diagnosis and a free, no-obligation quote. Our experts are here to help you get back on the road safely and efficiently.