Toyota Auris Hybrid 12V battery issue

What common does have burned squirrel nest and flat battery of the Toyota Auris Hybrid? Nothing actually but below is a story which contains both of these elements. Please read on!

Symptoms of Auris Hybrid 12V flat battery

I agreed with my wife that she can go to the grocery store while I will take care of our kids. Faster than an eye blink she came back frustrated and said that her car does not work. I quickly handed 6 month old boy back to my wife and went to see MY2017 Auris. Dead as a stone. Start button did not do anything.

First thing I suspected was 12 volt battery, it must be out of juice. My wife mentioned couple weeks ago that car flashed a warning of low voltage on 12V battery. After she mentioned that, I drove 45 minutes road trip to charge the battery. Warning message did not appear anymore. So we forgot that there was any issues at all in the first place. Oddly battery was empty now and car did not warn of low voltage again beforehand to remind us about the underlaying issue.

How to fix Toyota Auris Hybrid empty 12V battery

There is few options you can do to get car running again. You can do as I did and discard the car owner’s manual in the first place and fix the car like a man. So I went to local car parts shop and spend 65 Euros to the battery charger. Came back home (visiting first in the grocery store for my wife of course) and unboxed the battery charger and gave also a glimpse to the charger’s user manual. Nothing special there, connect red cable to battery’s plus pivot and black cable to car’s body (not to the battery).

I went to car and remembered that battery is located in the trunk. Tried to open rear hatch but it did not open. It was locked even other doors were unlocked. Then I remembered that I don’t have wife’s car keys with me. Grabbed those quickly from inside and went back to the car.

Rear hatch did not open still. It did not open because it is electronically controlled and car is now without energy. I decided to push over back seats and crawl to the hatchback Auris trunk, all the light I had was flashlight of the iPhone. I discovered battery quickly, connected cables properly and observed the battery charger. It says power on but it is not recharging. Why I wondered.

At this point I took car’s owner manual and checked what it says what to do in this situation. From there I discovered that there is actually plus pivot in the engine bay, even the battery itself is not located there. Which should be used in this type of situations. But battery charger did not charge even I tried to connect it through engine bay connection.

  • Open the hood
  • Locate and open big black fuse box (top right corner)
  • Locate and open red cover with plus labeling and open it
  • Connect battery charger / booster to the PLUS
  • Connect black / negative cable to the cars body. All metal parts inside the hood are grounded.

One alternative would be also to jump start Auris with my e-Boxer Forester but as it is a hybrid car also, I did not want to try this solution. Just wanted to avoid damaging Forester and not to get way too expensive repairing costs.

I then decided to call Toyota Info and ask for help. They suspected also that 12V is empty and sent me help through their partner company. After one hour of waiting service guy came and measured less than 4 volts reading from the Auris battery. He then connected a battery booster (portable battery) to Auris and then I was able to start the car like I normally would.

Low voltage readings was also reason why just purchased battery charger did not work. It was not powerful enough to get charging started. In this type of situation you really need to jump start the dead battery with other car or by battery booster.

Now it was important to recharge battery by keep car running 45 – 60 minutes. It is not necessary to drive at all but I decided to go for a 2 hours driving. To make absolutely sure it is fine for the next trip. Toyota’s Hybrid solution actually charges 12V battery from the hybrid battery pack. So that why it is not necessary to actually drive to keep car recharging smaller battery. Just keep car running for the required time, or go to drive and have some own time from your lovely family.

Root cause of Toyota Auris Hybrid 12V dead battery

It was little bit unclear what caused drain of the 12V battery. According to Toyota there was battery problems with model years between 2012 – 2014. My wife’s car is 2017 model, so that same problem should not be the case. My best bet is that something was left with power on, which then drained the battery. One possibility is that when she tried to turn car off, she kind of “double clicked” start/stop button while already lifting foot from the brake pedal making car have power on but the engine off.

Service guy mentioned that he had never towed Toyota’s Hybrid car because of the technical failures. There might be few cases if there was problems e.g. with tires but never problem with the electrics or other engine failures. Most reliable cars based on his experience.

I have also some experiences with Toyotas. 1988 Corolla (my first car), 2005 Corolla, 2007 Corolla, 2011 Hybrid Auris and 2014 Prius. 2007 Corolla had most problems, e.g. once I took it to Toyota’s service because of the odd smell in the cabin. Root cause was that a squirrel made a nest on top of engine, which then burned as engine get hot.

Update to the root cause

Wife’s Auris was staying in the garage a bit more than a week without being driven at all. Next time she tried to use the car, it failed start. So it was already second time with similar symptoms. This time I bought own jump start device and started car with that. We decided also to get car investigated by Toyota.

According to Toyota 12V battery was charging OK but it couldn’t hold the charge. So the ultimate solution was to replace faulty 12V battery.


  1. The issue with the 12V battery on Auris Hybrid was on the MY2012. Basically, the first batches produced (from 2012-10 to about 2013-06) had a firmware issue on the instrument cluster. If you slightly press the hazard button, but without any light flashing (not even the lamp on the instrument cluster), the whole CAN network was activated, but never deactivated. Therefore, after few hours, the 12V battery was drained. I experimented it also with the right tools to sniff the CAN network: car completely off, I also tried to lock it with the remote control but, despite that, after more that 5m the CAN network was still active (and draining the 12V).
    About in June 2013, an appropriate TSB has been published and a new instrument cluster firmware has been released to fix that issue.

    Liked by 1 person

    1. You are now a member of the Toyota Flat Battery Club.
      Along with loads of other people I have had the same problem with my new C-HR.

      My £5 Lidl toothbrush has a red led that illuminates when it’s battery is low.

      Toyota’s need the same.

      Why should we have to buy a £60 battery booster to start a new £35k car 😖😖😖


  2. I’ve had the same issue. Auris hybrid 2018. I keep a battery bank to start the car as I drive so seldom it nearly never starts on its own, even with weekly 1+ hour running of the car. I’m now going to try a solar trickle charger to keep the 12v topped up.

    This has happened even after recent major service and inspection by Toyota. Poor show by Toyota to have this problem IMO, a bit pathetic to need to nurse a quite new low mileage car as if it were an old temperamental collectors car.


  3. Did the solar trickle charger work? and which model did you purchase. I am the owner of a 2014 a Auris hybrid and even with a new battery fitted the battery soon goes flat. my car is not parked near any mains electric so a mains charger is of no use.


    1. The solar charger did not work, so I replaced the 12v battery and it seemed to do the trick for a few weeks. I stopped using the solar charger with the new battery. Then that battery died as well and I had to jump start the car with my battery bank, standing in the rain, late for what I needed to do.

      I’ve now started using the solar charger again, will see if it helps. Also running the car for an hour a week on the driveway, as I dont use the car very much.


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