2012 Toyota Prius Red Side Shot
Peter Neilson's picture

Can A Toyota Prius Run If The Battery Is Dead?

The Toyota Prius is simply one crazy awesome vehicle. Not only is it a great fuel sipping genius, but even when it is neglected. So what really happens when the traction battery no longer works? That is a great question, and we are about to find out.

When it comes to hybrids, there is not another company out there that has made more than Toyota. Through my adventures out on the road, I see them everywhere. Since there are so many, I asked myself a question. What happens when they all start to have the same problem with the hybrid battery?

To better understand this, I needed to first understand what the hybrid battery does, in order to see what happens when it does not work anymore.

What the Toyota Prius Traction Battery Does

The traction battery that we find on Prius is an energy storage device, as any battery is. It holds energy that can be used on demand. This energy is used to turn a motor generator inside the transaxle that either starts the gas engine, propels the vehicle at low speeds or aids in fast acceleration.

Toyota Prius Battery Block

The battery is responsible for an extra boost of energy that helps to make up the lack of power from the gasoline engine. This means the gas engine is smaller, and uses less fuel making it excellent for economy. The traction battery also stores energy that is being recaptured from the vehicle when it is coasting or in regenerative braking mode, which we can then use this energy in propelling the car forward.

Between these two examples we can see that the battery plays an important role in helping the vehicle drive and accelerate as a regular vehicle would.

What Happens When The Battery Fails

Should you encounter a P0A80 and have the hybrid battery fail, your Prius will actually still run, just more often. The car will still drive, but with a lack of power, as we do not have the needed available energy from the battery. The starting and stopping of the car will not be smooth as well.

Prius is a parallel hybrid meaning that if one of the components fails, the vehicle can still operate until it can be repaired properly.


The short answer to this question is yes,the Toyota Prius can still drive if the hybrid battery fails. You will get poor fuel economy and a rougher drive from it though. Should you encounter this issue, see you dealer or a qualified shop that can help you get it back into original driving condition.

I sure hope this helps anyone who has encountered a failed hybrid battery. Feel free to reach out to us on the Facebook group, Toyota Prius Owners Club for more help.

Check out tomorrow's story where I finally get to share my 2000+ mile road trip that I took in my Prius.

Peter Neilson is an automotive consultant specializing in electric cars and hybrid battery technologies. He is an automotive technology instructor at Columbia Basin College. He holds a Bachelor of Science in Automotive Service Technology from Weber State University. Peter can be reached on Linkedin and you can tweet him at The_hybrid_guy on Twitter.

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What is more common is a failed 12 volt battery. When that happens the car will not start or run because the electronics/computer does not have any power supply.
You Are A Genius. Not.
If the reaction battery completely how will the gas engine be started?
TL;DR: Not really. Impact can be mild to severe. A dead cell can result in "limp mode" where you basically have a 20 hp car, so 30-40 mph with the throttle pinned. Best case is as is described in this article, but the length of time between the mild issues described in this article and limp mode is usually short.
My experience exactly! Last year my 2008 had a battery vomit. Many of my dash lights were lit. My battery blower near the passenger-rear seat was at full speed. My cruise control was disabled. My ICE was running louder than usual, but I could still travel at my usual high speeds without nasty high rpms. I ran it like that for about a week. It got progressively worse. Until at the end when the ICE was revving really high without much acceleration. The car failed to move twice while driving 20 miles home. I had to pull over and "reboot" the car. Luckily I made it home, but after that it was dead, wouldn't move at all. The ICE would rev, but no movement. Turned out I had 1 little battery block fail out of the 28. I had it replaced with a refurbed block and all was good to go so far for over a year. So for me "limp mode" lasted around 150-180 miles.
I'm having that experience today on a 2005 model Prius. Just like a flashlight with 1 dead D cell among 4, it sometimes comes back to life acting normal, but within 10-15 minutes it goes back to dud mode: very slow acceleration, always-on fan, and noisy revving engine. But I was able to drive on the freeway, provided I use onramp that slopes down. Plan to replace the battery
Battery could also catch on fire. Then the games is over.
The chances of that happening are essentially zero. Vastly greater chance the fuel tank would explode than the battery. Nothing in the battery is flammable or explosive.
05 Prius the hybrid battery exploded it was like 4th of July almost caught fire can it be disconnect so car will run
You are wrong. As I have had two Prius and escape hybrid with battery failure. First you get the triangle of death then the car will run for a few blocks and die. It will restart then run a few blocks and die. It will not go above about 40. As the Prius uses the electric motor as the transmission it feels like a transmission problem. But it's the hybrid battery.
Sorry you are Incorrect the Toyota Prius (Gen1,Gen 2) Will not start or run if the Traction Battery is dead, Not sure where you are getting your Information from But you are Incorrect.
Mister torquenewsI have2011 prius with random hot and cold in 66degree when engine run but with hybrid battery ran cold . Have you got any opinions I bought it second hand with92345miles
Id t have a 2015 Prius V. 2 months ago dash lit up like a Christmas tree and display said "Hybrid battery failure. Stop immediately" I didn't and drove it home about 20 miles. Had it towed to Toyota and got the answer - POA80 dead battery, needs replaced. While there, had a recall on the computer system fixed, not the battery. Too much money- drove it home and the dash was clear. Drove it "doing ride share" for another 2 months -no problem. Today, all of a sudden, same thing but would run on the gas engine OK. Manual said to check some controls. not done yet. But seems to run ok on gas-but hybrid battery not charging. Display shows it is fully charged. I am perplexed. Do I change the traction battery? Or what?
I'm having the same experience, with one exception - the dealer just pushes me to a new car, has no interest in replacing the battery. I will have it replaced at a reputable independent repair shop. Sometimes it drives just fine.
Tested all the cells and they are all about 7.8 volts.
My Prius Main battery doesn't hold a charge very long. Will driving the car cause additional problem as I try to drive where the battery indicator stays blue. Will driving the car cause more future problems
Generally, the battery will just deteriorate until limp mode is achieved. Drivability will get progressively worse.
THIS IS NOT the case with my Prius. It has sat because of the pandemic. I tried to start it this morning and it is making a weird whining sound and does not start and the screen does appear.
Dead 12V. Can't leave cars sitting. They pull a continuous small current from the 12V battery. Will typically drain a healthy battery in 1-2 months.
Ive had the same issue, I replaced the 12v battery in June. Not cheap, 240 bucks ouch. I don’t drive it around because of the red triangle of death. I’ve been starting it at least once a day for a couple minutes. I don’t know how the hybrid battery recharges the 12v battery, but That lasted on a new battery for 4 months. Lights flickered yesterday letting me know it had enough, took the battery to Oreilly where I purchased it, 12v battery is good. I’m thinking of using a trickle charger to prolong the life of the 12v battery until I can get the hybrid battery worked on, who knows when but that should keep the 12v battery happy I hope. Any thoughts?
Bad idea. 12V is charged via DC-DC converter from HV system. "couple minutes" per day is not enough as you have discovered. If you intend to leave the car parked, remove the 12V and put it on a battery tender that will maintain it at full charge. More importantly, you should get the car diagnosed, so you know what's needed. Red triangle of death and accompanying lights can indicate dozens of possible issues.
I think all hybrids have no 12volt starter motor. The ICE starts using high voltage battery turning over the ICE connected motor-generator. So how would the ICE ever get started with a dead high voltage battery? I’ve never heard anything like a conventional starter motor on my Honda hybrid. Why would an automaker include a conventional starter when there is a motor-generator already attached to the ICE?
My sentiments exactly Paul! I have a 2007 Prius sitting with a dead HV battery, and it will not move one inch. I replaced the 12v battery hoping to get the ICE started, and it will not! Turns out the 12v battery only operates the accessories, and has absolutely nothing to do with starting the ICE. I just can't understand where the poster is getting his information from. Thanks.
Herb and Paul: sorry to dispute your posts but I've experience many (>10, two different Priuses, '05 and '07)) instances when my 12 volt battery was drained and the ICE could not be started, all of which occurred with a perfectly functioning traction HV battery. You may be correct that you need the HV battery to start the ICE, but likewise you need a charged 12 V battery as well. I'll leave it to an expert to explain-perhaps the 12volt battery delivers a voltage signal through the ignition circuit that engages the motor powered by the HV battery to start the ICE?
Below is my Toyota Prius 2017 hybrid car scan report, the gasoline engine has noise, looks like has transmission issue as gears look not changing on high acceleration, it makes noise with acceleration instead of getting gears automatically changed, the front high beams do not also work while their indicator on dashboard is lit. Year:2017 Make:Toyota Model:PRIUS VIN:JTDKB3FU9H3577800 Odometer:82383.00 Vehicle Information Vehicle Software Version:V50.52 Diagnostic Application Version:V7.05.018 Diagnostic path:16PIN DLC(Europe and Other) > Prius > ZVW50 > 2ZR-FXE > 2017.11- 2018.12 > Others > Others The following system is abnormal: HC (Hybrid Control) 4 problems exist 1.P058A01 Auxiliary Battery Monitor Module General Electrical Failure 2.P058A01 Auxiliary Battery Monitor Module General Electrical Failure 3.P058A01 Auxiliary Battery Monitor Module General Electrical Failure 4.P162B87 Lost Communication with Auxiliary Battery Monitor Module Missing Message Test Failed Pending Confirmed Confirmed System fault code ABS (Anti-lock Braking System)/VSC (Vehicle Stability Control)/TRC (Traction Control System) 1 problem exist 1.C1241 Low or High Power Supply Voltage History CM (Combination Meter) 2 problems exist 1.U0182 Lost Communication With Lighting Control Module Front 2.U0182 Lost Communication With Lighting Control Module Front BCM (Body Control Module) 2 problems exist 1.U0182 Lost Communication with AFS 2.U0182 Lost Communication with AFS ES (Entry&Start) 1 problem exist 1.U0155 Lost Communication With Instrument Panel Cluster (IPC) Control Module PDM (Passenger Door Motor) 1 problem exist 1.B2312 Power Window Switch of Passenger side door Malfunction RLDM (Rear Left Door Motor) 1 problem exist 1.B2313 Glass Position Initialization Incomplete RRDM (Rear Right Door Motor) 1 problem exist 1.B2313 Glass Position Initialization Incomplete PAC (Parking Assist Camera) 2 problems exist 1.U0100 Lost Communication With ECM/PCM 'A' 2.U0163 Lost Communication With Navigation Control Module The following systems are OK: 1.ECM (Engine Control Module) 2.CCS (Cruise Control) 3.EMPS (Electronic Motor Power Steering) 4.SRS (Supplemental Inflatable Restraint System) 5.AC (Air Conditioning) 6.TPMS (Tire Pressure Monitoring System) 7.MG (Motor Generator) 8.CGW (Central Gateway) 9.DDM (Driver Door Motor) 10.MSW (Master Switch) 11.RHS (Rain and/or Humidity Sensor) 12.PSC (Power Source Control) 13.NS (Navigation System) 14.BSM (Blind Spot Monitor) Master 15.BSM (Blind Spot Monitor) Slave Current History Current History History History Current Current History History