Common signs: fuel economy drops, the petrol engine runs more often, the battery gauge jumps around, a warning light appears, or the car goes into limp mode.
Before paying, check the warranty (Toyota covers hybrid batteries 8 years or 100,000 miles, and 10 years or 150,000 miles for model year 2020 and newer), then compare new, remanufactured and rebuilt options. Do not attempt high-voltage work at home. Also rule out the small 12V battery: see the 12V battery in hybrids and EVs.
The two batteries
A hybrid has a small 12V battery and a large traction (high-voltage) battery. Many problems that feel like a hybrid battery failure are actually the 12V battery. The car may refuse to start or show a flurry of warnings. Check the 12V battery first: it is cheaper, and you can price it with the calculator.
Warning signs of the traction battery
- Noticeable drop in fuel economy that is not explained by weather or driving.
- The engine running more often, or starting at odd moments.
- The battery gauge swinging quickly between high and low.
- A hybrid system or battery warning light.
- Loss of power, reduced acceleration or limp mode.
- A cooling fan for the battery running loudly or constantly.
What to do next
- Note when the symptom happens and take a photo of warning lights.
- Check your warranty. Toyota’s newsroom states 10 years or 150,000 miles for the hybrid battery on model year 2020 and newer, and 8 years or 100,000 miles before. Our hybrid calculator applies those terms.
- Have a hybrid-aware shop or dealer scan the battery. A cell-level report can tell you whether the whole pack is bad or only a few cells.
- Ask about options: new, remanufactured, rebuilt. Prices vary, and the Prius figures we have are on the calculator page.
- Get a written quote including fitting and warranty.
Can I drive with a bad hybrid battery?
Sometimes for a short time, but the car may lose power or efficiency, and in some cases it will not start. A warning light is a reason to get it checked soon, not to ignore it. Do not attempt high-voltage work yourself.
Used hybrids
When buying a used hybrid, ask for a battery health report, check the age and miles against the warranty, and ask whether any battery work has been done. A car near the end of its warranty carries more risk than one with a documented healthy battery.