Question of the week: Will a hybrid car still work if the drive battery is dead?
Fri, 28 Nov 2025
Dear Honest John,
"I'm thinking of buying an older Toyota Auris Hybrid to benefit from cheaper road tax.
What if the hybrid battery was not holding charge, or was dead - would the car still start and run like a petrol-engined car?"
- DP
Dear DP,
If the hybrid battery was in poor condition or even not functioning at all, the car would likely still drive as a normal petrol car, but the nature of any fault may dictate how the car behaves.
If the drive battery had just a fraction of original capacity it may well drive normally other than very little input from the hybrid system, whereas a battery that was entirely non-functional would likely cause dashboard warning lights.
The other factor is that a failed or weakened drive battery would also make it considerably less economical as you would be hauling around the extra weight of the hybrid system without any of the benefits.
If you are considering a used example a test drive should show up whether the hybrid battery is functioning, and you could also take the vehicle to a Toyota dealer or independent hybrid/EV specialist who can perform a diagnostic health check on the battery.
Hybrid vehicle drive batteries, particularly in Toyotas, tend to have a long lifespan, as they switch in and out during use, unlike the battery in a pure electric vehicle which is working whenever the car is in motion.
Toyota has refined and developed its hybrid system over the years to achieve a high level of reliability, evidenced by the number of Prius models that have covered 200,000 miles or more on their original battery.
