Toyota Yaris 2022 will NOT start: Solar panel's cable installed by dealer 

Thanks for your comment. It was very interesting and I have just watched a video and learnt a lot about CAN bus. Thanks 😀 There is a 90+ (!!!) page discussion of the Yaris' 12V battery issue on the Toyota Owners Club website. I have read bits of this discussion .... 90+ pages is just too much to read it all !!! ... and several people have mentioned that Halfords will fit a replacement 45Ah battery in the Yaris Mark 4. So Toyota could have factory fitted a 45Ah battery. Or they could replace a failed 35Ah batteries with 45Ah batteries but they choose not to do that .... Toyota choose to blame customers for not driving enough. I think that is a decision that will haunt Toyota for a long time because Toyota have lost their reputation for building reliable cars. www.toyotaownersclub.com/forums/topic/217673-12v-battery-maintenance-issues-etc/ In my case my car does UK average mileage per year so I do not believe that Toyota can blame me for not doing enough mileage.ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ctXDnI9uuYI.html When my car failed to start the AA jump started it and then accompanied me to the dealer. The dealer tested the battery and then they recharged the 12V battery overnight. They then left it for a few hours and then tested the battery again. They then passed the car back to me and told me that the battery was healthy - they also gave me the print outs of all the battery tests which confirm a healthy battery. So, if my 12V battery is healthy and I do enough mileage to keep it charged then the only option left is that something on the car was the cause of a big current drain that flattened my battery. It's very interesting reading about your Honda Civic because I am thinking along similar lines for may car's failure to start .... A few days before my car failed to start I received an official Recall Notice on my car due to a problem with the e-Call system. However, the problem was a software problem that could be fixed with an OTA update without needing to visit the dealer. I have had other OTA updates on the car and they all specify that the car must be on and in READY mode since this mode will charge the 12V battery and there is no risk of the OTA update causing a flat battery. However, the OTA to fix the e-Call system was different ... owners do NOT know when it is being done and have no way of checking if it has been done. I believe that this OTA could be accidentally done by Toyota when the car is NOT in READY mode. The letter just specified a period of time when my car would receive the OTA - not a precise date. It just seems a bit of a coincidence to me that my car starts OK for 10 months then during the window when the OTA to fix e-Call is done the car fails to start. I think Toyota did the OTA update the day before my car would not start and that something happened ... some error state with the OTA that resulted in my 12V battery going flat. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-XwY7m3xkybM.html The big problem is that modern cars are so interconnected with the manufacturer that they are never off and therefore you can never be totally sure of what they are doing and how much current they are drawing from the 12V battery. I am talking to Toyota GB about my theory with the OTA update to fix the e-Call system and they have just sent me an email to say that this OTA was done by Toyota Europe (not Toyota GB) so they cannot get any data about when my car received the OTA. I have not replied yet but my reply will make the point that I don't care if Toyota GB, Europe or Japan did the OTA update ... I just want to to know the date when the OTA was done and I expect Toyota GB to get that date from whoever in the giant multi-national corporate structure has that data !!!

The cable from the solar panel needs to be plugged into the OBD socket. The OBD has a 12V pin that is connected to the 12V battery positive terminal and can be used to trickle charge the 12V battery. This means that there is no need to connect the solar panel directly to the 12V battery. This is why the dealer installs the OBD cable is free of charge ... its very quick. I think there are a couple of screws to undo that hold the OBD socket in place which need to be undone. The solar panel's large OBD connector is then plugged into the OBD socket and then the OBD connector and the OBD socket can then be pushed back into the dashboard. The wire from the OBD cable is then just pressed into the trim with a tool and hidden on its route to the top of the dashboard. 15 minute job for a mechanic .... half a day if I was doing it!!! If the dealer had to lift the back seat and then securely and safely connect a wire to the 12V battery and then hide the wires from the rear seat to the dashboard this would take a lot longer and they would probably not offer this as a free cable install.

I remember you left a comment on another video saying that you were thinking of buying a Yaris. I hope the video helps you come to a decision. It is a really a very good car ... except if you are a low mileage user then this 'feature' of the hybrid system is a little bit annoying!!!

Yep, I agree I can live with this. But it's a Toyota and Toyotas are meant to be reliable. I understand that EVs and Hybrids from all manufacturers use small 12V batteries because there is no starter motor ... all the 12V battery has to do is start the computers so you only need a small 12V battery. I also understand that when a car is parked some of these computers are still working - a typical car - petrol, diesel, hybrid or electric - requires at least twice or much current when parked as an older car with less computers. This isn't a problem for petrol or diesel cars because they have a big 12V battery for the starter motor ... but it is a problem from hybrids and EVs because they only have a small 12V battery. I therefore accept that if I go for a weeks holiday and leave a hybrid in an airport car park it is possible that my car will not start. However, my car had a single day off and would not start which I find more difficult to accept. I had a 2018 Yaris Hybrid (Mk3) which had no problems starting even during COVID lockdowns which indicates to me that it is possible to design a Hybrid's 12V battery to cope with low mileage owners. I have come to the conclusion that the Yaris Mk4's 12V battery and/or the 12V recharging is working as designed. But my concern is that the 12V system's design is optimised for higher mileage owners but not right for lower mileage owners who run the risk of not being able to start their cars.

Car batteries are rechargeable batteries. In a petrol or diesel car the alternator charges the battery. In a hybrid or EV the 12V battery is charged from the big battery that powers the car's wheels. In a petrol or diesel car there is a big 12V battery that can turn the starter motor even on a cold winter morning. The 12V battery in a hybrid or EV only needs to turn on the computers that run the car so it is a small battery. The problem is that modern cars have a lot of computers and some of them are still running when the car is parked. The small 12V battery in a hybrid or EV can run out of power if you leave it in an airport car park for a week or more so that the car will not start. My car was doing 20miles per day for a couple of weeks & during that time had a couple of days without use about a week apart. Unfortunately it would not start after the second day without use. My dealer recommended using a solar trickle charger to keep the 12V battery topped up. They fitted the cable free of charge to make the solar panel easier to use.

We had the same issue. Car was totally dead could not lock it via the remote. Called out RAC who put some power into the 12v aux battery under the rear seat. However this is where it hits your pocket. I contacted my local Toyota garage confident the 10 year warranty covered it and was told we had not done ENOUGH mileage for the warranty to be relevant. The car is 3 years old in May 2024 and with under 12,000 miles their excuse was the battery is not getting enough charge due to lack of use.....!! That will be £140 thank you and we have non in stock they are on back order which suggests I am not the only one. Did kick up a stink without any result only the use of a solar panel trickle charger would prevent this or use it more. Er retired occasional use ?

Toyota's lack of use argument is bizarre given that there are absolutely no marketing messages that a Toyota Hybrid is only suitable if you do X thousand miles per year. I have put X because even in the 25 page discussion with 570 comments on the Toyota UK website there are no comments that I have read that indicate what is high mileage and what is low mileage that puts you at risk of your car not starting mag.toyota.co.uk/coronavirus-toyota-hybrid-car-maintenance/comment-page-1/#comments I don't think Toyota have understood the cost of the reputational damage for the brand which in the long term could be significantly higher than the cost of fixing this problem. There are many things that Toyota could do to help customer's manage the 12V battery ... some of my own ideas: - add a 12V battery voltmeter - it does not need to be on display all the time ... for example, it could be next to the tyre pressure display as you scroll right/left - add a warning message somewhere that would pop up if the 12V battery is getting low so that you can either leave the car in READY mode for an hour or put a battery charger on the 12V battery to avoid the car not starting - replace the 35Ah battery with a bigger capacity 12V battery. Halfords will do this. I guess Toyota dealers will not do this because they have to use Toyota specified parts. I think a bigger capacity battery will make the battery less likely to go flat but I am unsure if changing the 12V battery will affect other elements of the 12V system. Toyota could helpfully advise if a bigger capacity battery will be OK in the car and will not have any detrimental effects on the other parts of the 12V system Instead of the above ideas for constructive assistance Toyota are blaming customers for not doing enough miles. This is turning loyal customers like myself against Toyota and means I am unlikely to buy another Toyota. On future Toyota Hybrids I would like to see... - a 12V reset button similar to Kia and Hyundai which monitors the 12 battery when parked and if the voltage drops too low the 12V system is switched off completely. You have to get in the car with the mechanical key because 12V is off so central locking will not work. However, once in the car you just need to press the 12V reset button. No need to lift the bonnet ... no need to use a NOCO jump starter. - design a 12V system with a bigger capacity 12V battery which will mean that the problem is much less likely to occur - if Toyota believe that a solar trickle charger is the solution ... build one into the roof of future hybrids so that customers do not need to keep plugging the trickle charger in. OK a slightly tongue in cheek suggestion ... just to make a point that the solar trickle charger is not a solution ... its a work around.

I have read that space is very limited under the back seat near the battery. So, I think you need to be confident with DIY jobs in order to take on the job of installing connections direct to the 12V battery. Personally I would not take on the task of connecting direct to the 12V battery. I do not have a mains socket near my allocated car parking space so I don't have the option of plugging my 12V battery into an external mains powered battery charger ... which is another reason for not connecting direct to the 12V battery! The way my dealer installed the cable is not the perfect solution ... but its good for me because its FREE & does not require a mains socket ... and from my dealer's perspective its very quick which since they are doing it for free they do not want a job that takes a long time and requires additional cables, connectors etc. I think there are a number of ways of connecting trickle chargers to a Yaris - they all have pros and cons and in the end choose the one that is best for your own situation.

It certainly is, if you don’t want to remove anything more than the plastic cover in front of it under the back seat. I have actually bought the same device that you have - made in China; no surprise there. In my case, I’m content with the EOBD plug staying in, as it’s nowhere near my legs given my seat position etc, so the 12V cable plug is just by the air con output on the right hand side of the dash. We’ll see if it is actually useful in due course. Incidentally, leaving the plug where it is offers an easy point to measure the 12V battery voltage using an ordinary multimeter when I want to; it’s always live, being connected to pins 4 & 16 on the EOBD.@@Helpful-Stuff

I have bought a voltmeter that plugs into the accessory socket. I know that this is measuring the output of the DC-DC converter that is charging the 12V battery but I have figured out that for a brief period just of you start the car the DC-DC converter is NOT charging the car so I now always look at the voltmeter as I start the car and I see the 12V battery voltage. A load of the car's electrical systems are already on so the voltage has dropped from a totally unloaded 12V battery voltage but if I am comparing the same voltage every time I start the car then I will notice if the voltage is starting to drop and I should get some advance warning of the 12V battery failing to start the car. This video shows more about the voltmeter and the voltages to expect at start up and also as the smart charger switches between fast and slow charge ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-0nYdnNVgvJI.html

I don't do enough mileage for the car to keep the 12V battery charged so my dealer has recommended that I use a solar charger to trickle charge the 12V battery and keep it charged. If I don't do this then there is the risk that my car will not start. Hybrids and EVs have a small 12V battery because all it needs to do is start the computers in the car. All modern cars use a lot more current when parked than older cars. Petrol and diesel cars don't have a problem because they have a big 12V battery for the starter motor. Unfortunately the small battery in Hybrids and EVs end up with no charge if you leave them parked for several days in, for example, an airport car park. My problem is that my 10month old car would not start because the 12V battery had insufficient charge after a couple of weeks of around 20miles per day and a single day without use. Although I am unhappy with this I don't see that I have any other option than to use the solar charger to trickle charge my battery - as recommended by my dealer.

@@Helpful-Stuff This sounds like a parasitic draw issue more than anything else. Do a proper draw test first and figure out which module doesn't go to sleep properly. Furthermore this "hack" to remove the obd socket seems rather silly. They could've just used a fuse tap for example and hardwired the extension harness into the car. The only reason the solar panel has an ODB plug on it is because the plug has a constant 12V feed to it and it's the same on every car. Not having the port available anymore is making roadside assistance and safety inspections more difficult. Also a hybrid and EV can recharge the 12V battery from the hybrid battery when it's in the ready state (even the 1st gen Toyota Prius supports that). So there is absolutely no reason why the car couldn't recharge the battery sufficiently in a daily 20mi drive, unless something is wrong with either the charging system or battery.

I tried to phone Toyota GB to discuss the 12V system but they just transferred the call to the Service Manager at my dealer. I have talked with the AA man, my dealer and Googled. The Toyota Owners Club website has a 65 page discussion !!! in just one thread about the 12V battery issue. I have not read it all yet but it shows that a lot of people are having this issue and my perception is that the MK4 Yaris seems to suffer more than other Hybrids. I have just read is that 2 manufactures (Hyundai & Kia I think) have solved the 12 battery problem with a 12 Reset button. If the computer detects the 12V battery is getting low it will switch the 12V system off. This means that you need to get in the car with a physical key but you then just tap the 12V reset button then hit Start and the car will start. They then recommend that you leave the car in the Ready mode for 30mins to recharge the battery - I guess you can also drive it for at least 30mins. I have come to the conclusion that my car is working as designed. However, I think the design of the 12V system on the Yaris Mk4 makes the likelihood of the car failing to start much higher than with other models. I had a 2018 Yaris Hybrid that started every time - even during COVID lockdown when I was only using the car once per week. My dealer recommended that I buy the solar charger and they offered to fit the cable free of charge. I think my dealer has decided to do this slightly messy OBD cable fitting because it is quick and easy - I think he said its just 2 screws and takes well under 15 minutes. I agree there are more elegant ways of doing it - but not as quickly and with no parts required that are not in the solar charger box. The motivation for the dealer is to make unhappy customers happy again at very low cost. I must admit it has worked with me … I am happy & have full confidence with my dealer. I am unhappy with Toyota and not confident that my car will start every morning through the winter months. Not a good place to be … I have bought a NOCO Jump Starter as well as a Solar Trickle charger!!! I think it is also worth pointing out that for a dealer to have spent time looking at this 12V problem and developing the solar panel “fix” implies that the dealer has a lot customers who are experiencing problems with their Toyota Hybrid failing to start with a flat 12V battery.

The 12V battery is under the back seat behind the driver. The solar panel is supplied with a cable with battery clips but the cable is too short to get from the rear seat to the car's dashboard. I also think that the OBD plug is more secure than the battery clips which could work their way loose with the movement of the car.

@@Helpful-Stuffthe hybrid battery is at the back. The 12V is at the front I believe.

I am almost certain that the 12V battery is under the rear seat behind the driver ... the AA man pulled the cover off the rear seat on the drivers side and he said he wanted to check the 12V battery and get his battery tester connected to the battery contacts rather then the battery jump start contacts under the bonnet in the fuse box. He would not have wanted to look at the traction battery which is also under the rear seat.

@@anonymousgoat107 In the Yaris it is under the right-hand passenger seat. There is a + contact in the fuse box under the bonnet for jump starts that can be used for charging from some of the posts I've seen on the Toyota drivers forum. I'm testing it at the moment as I do not have the strength needed to tackle shifting/accessing the battery for charging.

@@verandisoldusty6834 please let me know how that goes. It'd be cool if helpful makes a video too!

Thanks to a comment from a Polish viewer I have discovered that Toyota Poland have provided their dealers with new 12V battery test equipment & procedures and any battery that fails the new tests will be replaced under warranty. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-EHtg81kM-FU.html I have not been able to discover if the new test equipment, procedures & warranty policy have been rolled out by Toyota GB. I have had comments from people about UK dealers who are profiteering from this fiasco by charging customers £144 to recharge and test their battery - if the battery fails then £144 is refunded. I think this is absolutely disgraceful and Toyota GB should stop dealers from doing this. My battery was recharged and tested as "healthy" but I now know it had been degraded when only 10 months old and it has been changed. I would have been charged £144 if this dealer was my local dealer. In order to ensure that my 12V battery is healthy I do a weekly recharge for 1 hour while I wash the car and I use the solar trickle charger on any days when I do not use my car. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Ch-L0JbbQUg.html I have got NOCO GB20 just in case my car fails to start again. I do this because I have to maintain the 12V battery charge in order to ensure I do not suffer from the inconvenience of another failure to start. The bizarre thing is I really like my Yaris Excel with Tech pack ... it has loads of fantastic gadgets (e.g. HUD, intelligent cruise control etc) so that I think it is the best car I have ever bought ... unfortunately at the same time it is also the worst car I have ever bought because it failed to start when only 10months old after just one day without use.