Yaris Hybrid electrical errors

That sounds like a classic auxiliary battery issue, especially with those kilometers. Has the battery ever been replaced? These Yaris hybrids are quite sensitive to voltage drops. Low voltage can cause all sorts of seemingly unrelated electrical malfunctions. Before jumping to conclusions, have you checked the battery's voltage yourself? And are all the connections clean and tight?

Good shout on the battery replacement! I actually haven't replaced it since I bought the car. I'll check the voltage with a multimeter tomorrow. Where exactly should I check for voltage drop? Are there any specific points on the auxiliary battery or the car's frame I should focus on?

Given that it hasn't been replaced, it's almost certainly the culprit, especially considering the error codes and symptoms you're experiencing. While checking the voltage is a good diagnostic step, at this point, I'd strongly recommend taking it to a qualified mechanic. A weak auxiliary battery in these hybrids can cause unpredictable power management issues. Continuing to drive with it could potentially damage other components. It's always best to err on the side of caution with hybrid systems.

Thanks a million for the advice! Dropped it off at the local garage, and you were spot on – it was the auxiliary battery. Cost me 290€ for a new one and installation. Feeling much better about the car now! Appreciate the help!

We are five owners, on two adjacent streets in Námestovo, with Toyota Yaris Cross Hybrid vehicles, purchased in 2022-2023, so they are still under warranty!!! Probability of starting failure??? Weak starting battery, 12V/35Ah /Pb/ ???!!!!, lead-acid. The manufacturer should have installed a 12V/45Ah, but a cyclical "AGM" battery... After our complaint on June 26, 2025, regarding this problem, Toyota Central Europe at Galvaniho 19 in Bratislava responded: "With this type of hybrid vehicle, it is necessary to drive more often, and if you don't drive? Then charge the starting battery weekly!" Toyota can give such a childish excuse and advice somewhere in developing countries, not in technologically advanced Slovakia!!! I propose replacing the batteries, but under warranty and not after the warranty expires, so that buyers do not have to pay extra for this replacement!!! The cars are under warranty, and it's a manufacturing defect!!! The car manufacturer, once the world's number 1 seller, Toyota??? It's time to wake up!!! So you don't end up at the bottom of the sales rankings! Otherwise, this will go to the media! §

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It's frustrating to deal with such issues, especially when the vehicles are still under warranty. If the starting battery is consistently failing, it might be worth documenting each incident and any communication with Toyota. This can strengthen your case for a warranty claim. Additionally, consider having a certified Toyota service center perform a thorough inspection to confirm the issue and provide a detailed report. This documentation can be crucial if you need to escalate the matter further. If you have any more questions or need further assistance, feel free to ask.

Should Toyota solve these starting problems by replacing the batteries, i.e., instead of the currently installed 12V/35Ah/Pb/!!! with types = 12V/45Ah/AGM/, in Yaris-Cross-Hybrid models still under warranty!!! ... and not tell owners that they will replace their batteries after the car warranty, with the vehicle owner paying an additional 290 Euros?!!! It's a manufacturing defect, or does the warranty not apply at Toyota?!!! / Listening to those childish excuses from the service-dealer, about more frequent driving and battery charging are really "childish"! After all, not all Slovaks are a nation of slaves! / Peter, NO

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The battery should be measured under load to check its capacity, not without load; it can show 12.5V even when unloaded!!! :-)

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It's understandable to be frustrated with the situation. If you believe the battery issue is a manufacturing defect, it's important to continue pursuing the matter with Toyota, especially since the vehicles are under warranty. Make sure to keep all records of your communications and any service reports. You might also consider seeking advice from a consumer protection agency in your area, as they can provide guidance on how to proceed with warranty claims. If you have further questions or need more assistance, feel free to ask.

It's understandable to be frustrated with the situation. If you believe the battery issue is a manufacturing defect, it's important to continue pursuing the matter with Toyota, especially since the vehicles are under warranty. Make sure to keep all records of your communications and any service reports. You might also consider seeking advice from a consumer protection agency in your area, as they can provide guidance on how to proceed with warranty claims. If you have further questions or need more assistance, feel free to ask.