Which? slams Toyota and Lexus for battery faults that left people locked in cars and owners out of pocket

Which? research has uncovered a major battery flaw in some Toyota and Lexus cars that can cause people to become trapped in their vehicles. 

Even in milder cases, we’ve heard from hundreds of owners of Toyota and Lexus hybrid cars who have suffered repeated starter battery failures, but have had to pay for battery replacements and charging kits. We think they should be refunded.

Which? has called on Toyota and Lexus to replace faulty batteries for free, refund those who have paid out of pocket and provide safety-critical information to all their customers who have electric door-opening systems that can be defeated by a flat battery.

Worse still, owner testimonies suggest that not only have franchised dealers been potentially mis-selling hybrid cars, but they have also been accusing customers of causing the fault – by blaming battery failures on their driving habits, such as not racking up enough mileage.

Flat battery locks owners in their cars

'The children were panicking and it was extremely stressful.' Mary

Electrically operated doors are an increasingly common feature on premium cars. The primary internal or external door handles don’t directly release the door; instead, they engage an electric motor to do so. 

These systems usually have a manual override that doesn’t need electricity. But, based on the testimony we’ve seen, it’s clear that owners need to be clearly informed how these work before a more serious incident occurs.

Michael, from North Lancashire, told us that the 12V battery in his year-old Lexus NX failed twice, resulting in the occupants becoming trapped in the car due to this model’s electric door-opening system. Unaware there was a manual door release and in a car with two adults and two dogs, Michael felt he had no alternative but to break a window to let air in. 

According to Michael, a Lexus main dealer initially agreed verbally that the battery was not fit for purpose, but the same dealer changed their tune the next day and refused to provide a free replacement. 

Michael told us: 'I refused to accept the car as it was unsafe to drive, and I decided to buy a new battery and glass at a cost of £278.30. We weren't given any plausible explanation as to why the battery failed.' 

Mary Mitchell told us that she ended up with her grandchildren locked inside her Lexus LBX with the keys. The car’s electrically retracting external door handles didn't seem to operate when the 12V battery was flat. 

The car does have a manual override inside, but the children didn’t know how to operate it. The key fob has an emergency mechanical key, but it was inside the car. 

Mary said: 'The children were panicking and it was extremely stressful. We eventually managed to get a window open and get the children out.' 

Mary’s local Lexus dealership replaced the 12V battery, but a year later it ran flat again. Mary told us: ‘[Lexus’] only advice was that this type of car isn't suitable for low-mileage usage and that it should be driven for a two-hour drive every week. I still like the car, but I no longer trust it.’

James Houston, from Northamptonshire, had a similar experience. He told us that his Lexus RX has had six 12V battery problems in its first year and that people have also been locked inside the car. 

‘Due to the loss of electrical power, [my wife] was unable to open the rear passenger door normally and became extremely distressed believing she was trapped inside the vehicle. Although there is a manual emergency release process, this isn't intuitive and wasn't clearly explained during vehicle handover.’

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What Toyota/Lexus has said

As a result of concerns raised by Which?, Toyota has published an article on its website on what to do if your 12V battery fails, including what to do when electrical door releases cease to function. We understand Lexus will be doing the same shortly. 

The company said: 'We will also be sharing this guidance with our retailer networks so they can help answer customer questions and reinforce awareness during customer interactions.' 

On the issue of electric doors, a Toyota/Lexus said: ‘We are particularly concerned by reports of customers feeling distressed or vulnerable as a result of a depleted battery, including incidents where occupants have experienced difficulty operating electronic door-release systems. 

‘Customer safety remains our highest priority, and we recognise the importance of ensuring customers are familiar with the manual override features fitted to these vehicles.’

Which?'s view

We’re pleased to see Toyota/Lexus is taking our safety concerns seriously. However, we think an information campaign that targets all owners directly – including those who have bought an affected car second-hand – is the only way to minimise risk. 

We have suggested using DVSA data and sending letters to all registered keepers of the affected cars in the UK, but Toyota/Lexus hasn’t yet detailed its approach. We'll update this story when we learn more. 

Toyota and Lexus dealers blaming customers

'They suggested I drive up a nearby dual carriageway for nine miles and back, twice a week, to keep the battery charged.' Sarah

Robin, from the East Midlands, was among dozens of owners who contacted us because they were told by Toyota and Lexus that their driving habits were to blame. 'Its main arguments were that we should do 10,000 miles per year or leave the car in Ready mode (this means powered on, parked) on the drive for at least an hour once a week.'

He added that he felt as though 'the dealer’s service department clearly had a script that they were going to stick to, no matter how daft parts of it sounded'.

After weeks of back-and-forth, according to Robin, the battery was eventually replaced. But when it failed again, Toyota wouldn’t replace the battery as it was outside of warranty and instead offered an 'upgraded' model for £200.

This is a story repeated across dozens of other emails received by the Which? Cars team. Most owners who claim they were told they weren’t driving enough were given a recommended range of 7,000 to 10,000 miles to avoid battery problems. 

According to the Department for Transport, the average non-business/commuting annual mileage driven by all cars in the UK is 4,500 miles, with business/commuting mileage at 7,100 miles. In other words, the verbal advice given by dealerships to the owners who contacted us far exceeds the mileage that most car drivers would manage in a year.

Would you buy a car if you knew this?

We think this could constitute a material omission under the Digital Markets, Competition and Consumers (DMCC) Act 2024. By failing to inform buyers that the vehicles require a minimum mileage to keep the battery working, which we think is a 'material omission' that directly impacts the car’s usability and would have changed their buying choice had they known. 

Multiple owners told us they wouldn't have chosen their cars had they known about the minimum mileage quoted by Toyota dealers when problems arose. 

Justin from Buckinghamshire’s Lexus NX battery has failed four times since October. 'I've been advised by it that I should drive the vehicle for an hour each week and should really be driving more than 8,000 miles a year, which I've never achieved in my driving history.' 

He added: 'I've lost faith with the car and find the situation with the battery ridiculous in the 21st century.'

Sarah was told by Toyota that driving her Yaris Cross 5,000 miles a year wasn’t enough. ‘It suggested I drive up a nearby dual carriageway for nine miles and back twice a week to keep the battery charged.’ Facing this unrealistic prospect, Sarah instead spent £60 of her own money on a solar charger.

It was a similar story for Donald, from Derby. Despite having driven his car more than 14,000 miles in less than two years, he told us that Toyota blamed his C-HR’s battery problems on his usage patterns. 

Donald said: ’Having lost confidence, I insisted on a new Toyota battery (for £190) to avoid further stress and anxiety. I'm 84 and expected the car to be reliable.'

After multiple battery problems with his Toyota Yaris Cross, Graham from Glasgow was told that a battery inspection would cost £160 and that the fee would only be refunded if a fault was found. The replacement would then cost £195. 

Graham told us: 'I decided not to risk this amount of money and took the car to Halfords. They fitted a new battery for £95 and supplied a four-year warranty. The car has been fine ever since.’

We’ve asked Toyota to refund anyone who felt compelled to buy a new battery because they believed their driving habits were to blame.

What Toyota/Lexus has said

‘Since becoming aware of customer concerns, we have continued to monitor vehicle performance and have taken a number of proactive steps as part of our commitment to continuous improvement. 

'Any discussion regarding vehicle usage is intended to form part of a factual technical assessment intended to help identify the cause of an issue and determine the most appropriate resolution, not as a criticism of the customer.’ 

The company also told us that since our first story on this topic, it has run online training sessions for its retailers focusing on 12V batteries, and how to better support customers with these issues. It added: 'These sessions are intended to reinforce the latest technical information and support customer communications across the network.'

Toyota/Lexus also told us that customer service pathways for this issue already exist, that each customer would be treated on a case-by-case basis and that, since our original story in May, it has improved some aspects of its battery diagnostic tools. 

It also says its battery inspections are free for customers concerned about battery performance. 

Which? view

Owner testimony suggests that free inspections aren’t always being honoured by main dealers, and Toyota isn’t committing to providing refunds. 

We have reiterated that we don’t think anybody should be left out of pocket by these issues and that we're concerned that owners who were denied a free replacement in the first instance might have been eligible for one had Toyota/Lexus’ improved battery diagnostics tools been available sooner. 

Extra expense: solar and trickle charges

'The instructions from Toyota place an unacceptable burden on the owner to maintain battery health.' Simon

Some owners felt obliged to buy a ‘trickle charger’, which is either a battery or solar panel to keep the 12V battery topped up. These types of chargers can cost more than £100. Some Toyota/Lexus dealers stock them, since they form part of Toyota’s official advice for maintaining 12V battery health. 

In some cases, owners said that replacement batteries fixed the problem, but others said their replacement performed no better than the first. It suggests a mix of issues, including poor-quality batteries, software problems and unresolved power-draw issues that Toyota seems unable to fix. 

Simon Wallace, from Cockermouth, summed it up: 'The instructions from Toyota place an unacceptable burden on the owner to maintain battery health.’ 

Which? was also surprised to learn from one owner that a main Toyota dealer had offered to modify a Toyota Yaris to make it easier for the owner to plug in their solar trickle charger. The modification in question was to make a hole in the plastic panelling surrounding the steering column and wire a plug into it. 

We advised the owner against having this done until we’d received clarification from Toyota that this is an official fix. Toyota has since confirmed this is not an official service that main dealers carry out.

What Toyota/Lexus has said

As above, the company has told us it is taking a case-by-case approach to expenses incurred as a result of the issues highlighted in our story.

Which? view

We don’t think it’s right that owners have had to spend more money on a solution that seems so commonplace that Toyota and Lexus dealers stock it and can make extra money from the sales of these devices. 

What you can do

Toyota/Lexus told us owners can contact Toyota directly from its contact page. It has said to contact dealerships in the first instance, and then come directly to Toyota's national customer service. 

The company said: 'As with all customer concerns, we remain committed to assessing cases fairly and ensuring customers receive the support and guidance most appropriate to their situation.' 

If you contact Toyota/Lexus for a refund or compensation for battery problems, please let us know how it goes by emailing the Cars Team at cars@which.co.uk. We read every email, but we can't reply to all of them.

Which?'s full list of demands to Toyota/Lexus

We’re calling on Toyota/Lexus to completely rethink its approach to 12V battery problems. While some owners have had successful battery replacements, many others haven’t and have felt entirely powerless to argue with Toyota and Lexus main dealers, who consistently blame their low mileage for the problems they’re experiencing. 

While Toyota correctly says that 'battery-related considerations and customer guidance exist across the automotive industry', we think the statistics from our car survey plus owner testimony show that other car companies simply don't have 

We believe the companies’ actions may be in contravention of consumer law, including Misleading Omissions under the Digital Markets, Competition and Consumers (DMCC) Act 2024 by failing to inform buyers that the vehicles require a minimum mileage to keep the battery working, which we think is a 'material omission' that directly impacts the car’s usability and would have changed their buying choice had they known.

We also believe the companies may be in breach of the Consumer Rights Act with cars that are both of unsatisfactory quality and unfit for their intended purpose. 

Toyota said: 'Toyota takes its legal obligations very seriously and complies with all applicable law in relation to the marketing and sale of its products.'

Our demands of Toyota and Lexus include:

• Immediately instruct main dealers to stop victim-blaming owners by telling them they drive an unsuitable number of miles a year

• Tell prospective buyers of affected cars, verbally and in writing before purchasing, how far they will need to drive the car a year to avoid reliability problems

• Provide refunds to anybody who has paid for a battery or trickle charger out-of-pocket, regardless of car or battery warranty status

• Provide free battery inspections to any concerned owners

• Invest in software updates that reduce power consumption and accurately tell drivers the state of their battery

• Inform all owners of cars with electric door switches of how to access internal and external manual door release

We’re continuing to monitor Toyota/Lexus’ responses to our findings and will follow up with the company and owners who contacted us to determine whether affected customers are being treated fairly. If we remain unsatisfied with the company’s response, we may complain to Trading Standards and the Competition and Markets Authority on behalf of owners.