Toyota Auris owners – 12 volt flat batteries

2012 Toyota Auris Hybrid

As part of Toyota’s rigorous quality control programme, we have investigated the cause of a 12 volt flat battery issue that has left some Toyota Auris drivers unable to start their cars after only a short period without use, usually a couple of days.

We would like to apologise for any disappointment and inconvenience that may have occurred as a result of this issue. But we can now confirm that the cause has been identified and a permanent solution developed.

The following information only applies to any Toyota Auris (including Hybrid) produced between December 2012 and February 2014. If you have an Auris produced after February 2014 your vehicle is not affected by this issue. No other models are involved.

Toyota Auris Hybrid Flat Battery: What causes the issue?

The issue is caused when the hazard switch is partially depressed for a very short period of time, incorrectly activating the car’s CAN-bus electrical communications system. This draws a constant flow of current that can discharge the 12 volt battery if the car is left unused for several days.

How can I prevent this from occurring?

Toyota has published a Technical Service Bulletin to its dealer network advising them of a permanent solution to this issue. The bulletin contains information and software files that will enable technicians to modify the software of the car’s combination meter. This update will prevent the incorrect activation of the CAN-bus system and prevent any potential flat battery concerns arising from this area of the vehicle.

If you still have concerns regarding the 12 volt battery of your current generation Toyota Auris then we recommend you get in touch with your nearest Toyota dealer for further assistance.


  1. With all the extra ancillary kit on the EXCEL HSD it needs a higher capacity LV battery. I was told it was only a problem with EXCEL spec HSD cars and I have been monitoring mine via the service screen. Even when it is used every day the service screen shows 11.9v after a couple of days. It may be a deep cycle specialist battery but 35aH is still very small for the start up load . I have had no problems yet (5 months) but a flat battery in my garage with the rear door locked would be a real challenge.

    1. Thanks for your post Ian.
      Hope these details have helped clarify the issue. Just to mention one point though, the 12v battery fitted in a Toyota hybrid does not need the start up load of a conventionally powered car. This is because it does not need the energy required to turn a starter motor, instead it is just opening up a series of relays as the larger hybrid battery will be starting the engine.
      Hope this helps.

      1. Hi David,

        Thank you for the update, very interesting! Such issues can arise with brand new models which shows although some testing happens before released, not every possibility can be so it relies on a large user base (us!) to find such problems. What pleases me is a manufacturer who will put hands up, admit an issue and fix it! So personally for this particular issue I’m happy if it’s quickly fixed. Let’s hope a software update is soon forthcoming so the ECU isn’t left fully alive waiting for a second signal from the switch that never arrives with it! From a distance this seems like a “timeout” implementation issue which should be do-able! How will this be communicated to all HSD owners?

        One thing I’d like to ask about aux. battery rating: When I was in local Toyota dealership the other day trying to get my spare wheel sorted (the doc. sheet Toyota dealerships have for this is wrong as the parts don’t fit properly – I need to speak to someone about this) they volunteered exactly the same info on this 12v issue as you stated and the temporary button press “fix”. Their own sales person’s cars are going flat (embarrassing) and they (Toyota!) wonder why the decision was made to put a smaller Auxiliary battery in the new Auris than the Prius. Apparently the Prius aux battery is a larger capacity. Is this true? If so why would a vehicle with the same HSD drivetrain as the Prius get a smaller Auxiliary battery as surely the differences in electrical systems are negligible?


      2. Hi Andy
        Thanks for your reply and glad this post has been useful for you. We will be updating this as soon as we have a resolution and we appreciate your comments about this. Turning to your question regarding battery output between Prius and Auris hybrid, the battery rating in the Auris is smaller than that of Prius. This is because the electrical systems are very different, the logic in the body ECU is such that the battery is designed around the ECU functionality so it did not require the same output.
        Hope this helps but let me know if you have any other questions.

      3. Clearly from what Andy said, the Auris battery was badly designed around the ECU. Forecourt car batteries going flat is hardly something you want.

  2. Hello,
    I would like to know the difference between 2013 and 2014
    is there the smae problem in battery
    Am from Egypt by the way


  3. Thank you for this helpful and informative post, which I only found by searching online after having to call out the breakdown service yesterday to a flat battery on my May 2013 Auris 1.6 petrol. When I spoke to my Toyota dealer today they seemed non-committal until I read this post to them. I was left with the clear impression that they knew about the problem, but weren’t saying anything until they’d heard something definite from Toyota.

    What is the likely time-scale for the permanent solution please? I can appreciate that it may take a little time to come up with a permanent solution (which must surely involve a recall), but in the meantime wouldn’t it be wise to notify owners of subject vehicles of the situation and the checks which can prevent an unexpected flat battery? If I had known about this last Friday, it could have avoided a breakdown on Sunday! It wasn’t a crisis – but it easily could have been.

    1. Hello Angus
      Thank you for your post and we are very sorry to read of your experience.
      As the post confirms, we are aware of the problem and working very hard to rectify this. We are waiting for more details regarding the time scale involved but do not anticipate this taking too long from now. Just to clarify one point though, it will not be a recall as these are only associated with issues relating to safety, but it will involve us (via out network) notifying Auris owners to return to their local dealer at their convenience for the rectification to take place. We will be posting further news on our site as soon as we are aware of this.
      Hope this helps for now but do let us know if you have any other questions.

      1. Hello David,

        Thank you for this clarification. I think it would be helpful if your dealer network notified relevant owners of the contents of your original post without delay, rather than awaiting the final solution.

      2. Hello David,

        I have just been on the phone to my Toyota dealer to book my car in for its first annual service in May. I mention the flat battery problem in the hope that the promised solution would be in place by then so I could kill two birds with one stone and avoid a second visit to the dealer. My dealer claimed to have no knowledge of this problem whatsoever. This is a ridiculous state of affairs and I felt as if I was being treated as an idiot from another planet.

        Questions, please:

        1. Have your dealers been alerted to the flat battery problem. If so, when and how. If not, why not?

        2. When will the promised solution be in place? I believe ‘late March’ was mentioned at one time.


      3. Hi Angus,
        Sorry to hear of your experience.
        We are in regular communication with our Dealer network and this issue was communicated on 12th February, apologies for any confusion caused.
        We can confirm the solution has been reached and the resolution will include a software upgrade. We are currently in the process of distributing the software to our UK Dealer network.
        In terms of time frame, this should be within three weeks, although we will add a further blog post as soon as we can confirm this schedule.
        Hope this helps.

  4. I have a 2013 Toyota Auris Excel 1.6 Petrol (Non-hybrid). I like most things about the care BUT within a week of purchase from new, the car failed to start due to a flat battery. The battery was tested first by the A.A. then by Toyota engineers, with no problem discovered. I had the same experience a few months later, the battery was re-tested … again nothing found. Today the same thing happened for the third time. My local (helpful & supportive) Toyota dealer seems as mystified as I am, but has fitted a new battery. I have read the theory relating to the hazard warning switch, but am a bit dubious about this as an explanation in my case. I wonder if other Auris (non-hybrid) owners have experienced something similar.

    1. Hi Phil
      Thanks for your post.
      In view of your comments we would recommend that you try this, particularly if the car is going to be left for several days. Otherwise your local Toyota dealer will be able to help you.

  5. I first had this problem with my 2013 Auris Excel hybrid on 15th January therefore I’ve been sitting with a faulty car for 9 weeks now. The car was taken to the dealership who kept it for 2 days and then denied there was anything wrong with it.

    After a second failure a week later the car was with the dealership for a week. They were testing it on advice from the Toyota UK technical bods. In the meantime I found the info re the hazards via the internet as it had been occurring in Italy and Germany plus a few cases in the UK. Having supplied the info and internet links to the dealership Toyota UK still denied that this was a problem. When they later admitted what the problem is you can imagine my anger as the problem has been known about since at least January.

    My local dealership have been very helpful throughout and are suitably embarrassed by the situation however I feel let down by Toyota UK over this. I was told a software rewrite would be available in 3-4 weeks but we’re long past that now. Meanwhile I have had a faulty car for two months.

    I was initially advised to drive the car for 20 mins every day to keep the battery topped up (inconvenient) and then advised of the workaround on 13th February so have been using it since then (for almost a month) but have a constant worry that I’ll forget to do the workaround and have a flat battery at a time when I really need the car. In short, I don’t have the fully functional car I paid for and am fed up with the aggravation of it. I get the distinct impression that this is not a priority for Toyota. The sooner Toyota get their collective fingers out the better.

    To add insult to injury I’ve received a marketing email today with the subject line – ‘How healthy is your Toyota Hybrid?’ Oh how I laughed.

    1. Hi Tom
      Thank you for your post.
      We have seen your email through to our customer relations team who will be in further touch with you. We should mention that a resolution is now available for this issue and your local dealer will be able to rectify this for you.
      Hope this helps.

      1. Hi David,

        Just read my inbox thread update to find:-

        “We should mention that a resolution is now available for this issue and your local dealer will be able to rectify this for you”

        When was this and exactly as I had previously asked, why wasn’t this communicated to all of us with a problem? I had hoped for a bit of a “release statement” on it at least rather than yet another disgruntled owner having a winge to be the way we find out that the fix is now here!!

        What is the fix exactly?

        Kind regards,

      2. Hi Andy
        Thanks for your post.
        We have established a resolution to this issue (which involves updating the software) and we are now in the process of obtaining the necessary equipment to distribute to our UK network. Once this is completed we will update this post so that owners will be able to book in their car for this to be undertaken. We will certainly keep you posted on this.
        Let us know if you have any other questions.

  6. I contacted Toyota Customer Services as I’d read the fault had been identified and new production is now OK. I wanted to check before buying Auris Excel Hybrid.
    Reply – what battery problem ?
    When I gave fuller information I was advised to take my car (not yet purchased) to my local dealer
    and it would be fixed under warranty.
    Pathetic. There is no recall in place for “older” cars, so one can only assume, nothing is resolved.
    A lost sale.

    1. Hi Bill
      Thank you for your post.
      We now have now resolved this problem (via a software update) and we are currently working with our network to fix outstanding vehicles.

  7. Purchased a Toyota Auris Excel 1.4 D, on 31st Jan, experienced a flat battery on Monday 10th March, on returning to the car after a week away. Called the AA out to the airport, the battery was charged up allowing us to drive home. We were not very pleased. Informed Toyota delership in Wolverhampton from where the car was purchased, and took the car there the next day. The sevice manager took the car into the workshop where the systems wre checked, on return after an hour the manager explained all systems were ok, but then explained the probable cause of the flat batery was the hazard warning switch, He then went though the process to prevent this happening. He then advised he was awaiting a permanent solution from Toyota. Full marks to the sevice manager. But sales staff should have advised us of a potential problem. Toyota have a big PR exercise to win back confidence in their products. Having two sons who have just bought new Hyundi i-30’s they keep reminding me that they dont have flat batteries.

    1. Hello Keith
      Thanks you for your post and we do apologise for the inconvenience you were caused.
      We understand your comments and are sorry that you were not advised. We are in the process of arranging rectification of this issue with our dealer network and will post an update on our Blog soon.

  8. I am having frequent battery problems with my Auris, purchased April 2012. I know your post describes only cars from Dec 2012, but is it possible that this is occurring in the earlier model too? My car is back at the dealership for the second time, and as yet they are unable to find the problem. They have had my car for three days now, and likely to keep it for longer, unless they find the source of the error. I can live without it for a bit longer but this shouldn’t happen to a car of only two years old. The service from the garage has been great so far, but given all of this information I have found, I am surprised no one mentioned this as a possible cause.

  9. Hi, If I wish to use one of the 12v aux sockets in the car. Should the car be in the ‘ready’ state or in ‘power on’ ie one press of the power switch with foot off brake pedal? Please explain in which modes will the 12V aux socket be powered without affecting the 12 V battery? thanks

    1. Hi Andrew
      Thanks for your post.
      The answer to your question is “ready”. We recommend this because, when in this mode the vehicle will use the engine which can then recharge both batteries as necessary. If only using in “power on” (ACC mode) there is a risk that you may drain the battery. The sockets will work in ACC mode but they will not work when the ignition is off so that anything connected does not drain the battery.
      Hope this helps.

  10. Hi David, Thank you for your response. Please can you confirm ‘Ready’ mode will be with the gearbox selected in Park, with indicator light on. Obviously I don’t wont the to move!

    1. Hi Andrew
      You are correct. In ready mode but with the car in Park.
      Hope this helps but let us know if you have any other questions.

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