Toyota and its premium sister brand Lexus are carmakers that are synonymous with reliability, but their iron-clad reputation has been called into question by a new Which? investigation.

Some of the companies' latest hybrid models are suffering battery gremlins that can leave owners and their family members and friends trapped inside their vehicles, the consumer group says.

The issue is particularly concerning in Lexus models fitted with the firm's 'e-Latch' system, which uses electronic interior door-release buttons instead of traditional handles.

If the car's 12-volt auxiliary battery fails or runs flat, the electronic system can lose power and the doors may not open using the standard button release.

While there is a mechanical back-up system in place, many owners who have been trapped inside said they were unaware it existed and claim they were forced to smash windows to escape.

Customers who have returned their vehicles to dealerships after their 12V batteries drained surprisingly quickly say they were told their cars need to be driven for up to two hours every week to keep it sufficiently charged.

Lexus and Toyota have acknowledged the issue and this month published a 1,500-word articles on their websites explaining how owners can deal with the problem.

However, Which? says the manufacturers should replace faulty batteries free of charge and provide owners with clear, safety-critical guidance on how to open malfunctioning doors.

Which? first raised its concerns around the high volume of 12V battery problems Lexus and Toyota cars were suffering in May.

Since then, around 270 motorists have contacted the consumer group to report similar issues, with more than three-quarters of these owning models from the two Japanese manufacturers.

The findings are particularly embarrassing for Lexus given that its e-Latch system has won praise for its safety credentials, even being recognised at France's Automobile Awards in 2021.

The electronic door-opening system uses sensors and cameras to detect approaching cyclists and pedestrians. If someone is about to pass the vehicle, it prevents the door from opening to avoid a collision.

However, some owners say the system is leaving them unable to open the doors at all when the 12-volt battery fails or becomes depleted, which appears to be a common problem with some cars.

Almost three in ten owners of the £30,000 Lexus LBX said their vehicle had suffered a battery fault in the past year, according to respondents to the latest Which? Car Reliability Survey.

Nearly two in five Toyota Yaris Cross drivers also reported battery issues, almost four times the average rate across all hybrid cars, which stands at 5.6 per cent.

Which? warns that flat batteries can have 'potentially dangerous consequences for owners' if they or other occupants are locked inside.

This is especially the case following crashes or in the event of fires if occupants can't escape quickly. This is why China will be banning concealed door handles in new cars from next year (scroll to the bottom of this article to read more about that). 

One owner, who asked to be identified only as Michael from North Lancashire, said the 12V battery in his year-old Lexus NX failed twice.

He claims the failures left occupants trapped inside because the e-Latch release button would not operate.

Models fitted with e-Latch also have electronic exterior door handles with a strip behind them to identify when users want to open the doors. 

Unaware there was a manual override, Michael says he and two other adults, along with two dogs, were stuck inside the vehicle and had no alternative but to smash a window to let air into the cabin.

After taking his Lexus - which costs from £47,000 - to a franchised dealership, he said staff declined to provide a free battery replacement or repair the broken window.

'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 were not given a plausible explanation as to why the battery failed.'

Mary Mitchell, who owns a Lexus LBX (which has e-Latch as standard across all trims), said she returned from a week's holiday and drove the vehicle to her son's nearby home without any issues.

However, when she loaded her grandchildren into the car later that day for a trip to the pantomime, the vehicle would not start.

When she went to speak to her daughter-in-law in the house, she returned to discover the children were locked inside with the keys.

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

'We eventually managed to get a window open and got the children out.'

After calling the AA for assistance, Mary says the same problem happened again a year later when the vehicle had been parked for only a few days.

She claims a Lexus dealership blamed her driving habits for the repeat battery woes.

'They were less than helpful and their only advice was that this type of car is not suitable for low-mileage usage and should be driven for a two-hour journey every week,' she said.

'This is not realistic for me and I don't feel that a car with these limitations can realistically be described as fit for purpose.'

Mary is not alone.

Several Lexus and Toyota owners told Which? they were informed by dealerships that battery failures were linked to poor 'usage patterns'.

One owner claims they were advised by a staff member in a dealership to 'drive up and down a nearby dual carriageway for nine miles and back twice a week to keep the battery charged'.

Others say they were told annual mileages of between 5,000 and 8,000 miles - well within the spectrum of the UK average of around 7,100 miles a year - were insufficient to keep the battery in good working condition.

Which? believes this could amount to a breach of consumer protection law, including potential misleading omissions under the Digital Markets, Competition and Consumers Act 2024, if buyers were not informed that vehicles require a minimum level of use to maintain battery performance.

Lexus says on its website: 'The 12V battery supports a range of vehicle systems and, like any battery, its condition can be influenced by factors including vehicle usage, driving patterns, battery age, environmental conditions and electrical demand.

'Regularly undertaking very short journeys or leaving a vehicle unused for extended periods may affect battery charge levels over time.'

James Houston, from Northamptonshire, told Which? that his Lexus RX – which starts from £63,500 new – suffered six separate 12V battery problems in its first year.

He said one incident left his wife trapped inside the vehicle.

'Due to the loss of electrical power, she was unable to open the rear passenger door normally and became extremely distressed, believing she was trapped inside the vehicle,' he said.

'Although there is a manual emergency release process, this is not intuitive and was not clearly explained during vehicle handover.'

The Lexus RZ and ES are also fitted with the e-Latch system.

Had Michael, Mary and James been told by sales staff – or checked the owner's manual – they would have been aware of the manual failsafe. 

Occupants can put a finger behind the door button and pull it out twice to unlock it from the inside. From the outside, there is a concealed manual release within the outer door handles that allow owners to get inside when the battery is flat.

Both would be extremely difficult to locate if you were unaware they existed at all. 

Toyota models continue to use conventional interior door handles, meaning occupants cannot become trapped inside in the same way as some Lexus cars.

However, owners of models including the C-HR, Corolla, Yaris and Yaris Cross have reported being locked out of their vehicles because of the battery running flat.

Following the earlier reports from Which?, Lexus and Toyota this month published guidance explaining how owners can access vehicles when electronic door systems stop working because of a faulty battery.

A spokesman for the brands told Daily Mail and This is Money: 'Toyota and Lexus take all customer feedback seriously and understand the inconvenience and concern that can be caused when a vehicle experiences a 12V battery-related issue.

'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. 

'These include the introduction through our product development activities of higher-capacity and higher charge acceptance batteries on a number of models, enhancements to customer-facing connected services, improvements to battery diagnostic processes, the release of updated battery testing software in May 2026 and the continuation of free-of-charge battery inspections.

'We are committed to supporting customers who raise concerns about their vehicle. 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.'

In relation to those unable to open the e-Latch-operated doors on Lexus models, the spokesman added: 'We are concerned by any situation in which customers feel distressed or unsafe, and we recognise that incidents involving occupants being unable to operate electronic door-release systems can be particularly upsetting, especially where children or pets are involved.

'Vehicles equipped with electronic door-release systems have manual override mechanisms which allow doors to be opened in the event of a loss of electrical power. Instructions on how to operate these systems are provided in the owner's manual and are available online and through our retailer network.

'We recognise the importance of customers being familiar with these procedures and, as an immediate step, we will create new customer-facing guidance explaining how to enter and exit a vehicle safely in the event of a loss of electrical power through our websites and customer magazine channels, as well as re-communicating this information to our Toyota and Lexus retailer networks to support consistent customer awareness and understanding of these features. 

'We will also review any further actions we can take to support customer awareness and accessibility of these procedures.'

The issues come just months after it was announced that the China will introduce new laws banning hidden door handles on new cars from next year as safety concerns mount regarding the pop-out features that were popularlised by Elon Musk's Tesla electric vehicle brand.

The handles, which are designed to be minimalist to both improve the aesthetic and aerodynamics of new cars, have come under significant criticism from drivers and road safety groups in recent years.

Motorists frequently complain that they freeze shut during winter and won't open. But more concerning is that they've been found to lose operation when involved in a crash, making it difficult for emergency services to reach passengers inside stricken vehicles.

The new rules could prompt car makers globally to rethink vehicle designs, having faced mounting pressure to reconsider concealed handles since they've become increasingly common after the arrival of Musk's first mass-market car, the Tesla Model S, in 2012.

Other brands including Audi, Jaguar Land Rover and Renault also use pop-out handles on some of their models.

With China increasing its power within the automotive sphere, analysts believe the new safety standard it has set could snowball across global markets.

The new rules, which were announced by the Ministry of Industry and Information Technology on Monday, will take effect from 1 January 2027, and require door handles fitted to new models to have both interior and exterior mechanical releases.

Have you been hit by this problem? Get in touch: editor@thisismoney.co.uk