Britain’s second best-selling EV has a ‘potentially dangerous’ issue, warns Which?

One of Britain’s most popular electric cars has a ‘potentially dangerous’ issue that could put drivers and other road users at risk, according to a consumer watchdog.

Product testing group Which? says it identified the problem with the UK’s second best-selling EV, the MG 4, during controlled and repeated tests that it carries out on over 100 different cars each year.

It found that the £27,000 EV’s lane-assist system – which is designed to keep the car in its lane to stop drivers veering over the white lines – pulled the vehicle onto the wrong side of the road, which potentially puts motorists at risk of driving head-on into oncoming traffic.

The EV in question, MG’s 4 EV, which has been widely regarded as one of the best electric cars on the market currently.

Last year, 21,715 were registered in Britain. Only the Tesla Model Y was bought in greater numbers in the EV marketplace. 

The findings fly in the face of the MG4s five-star rating from Euro NCAP – the crash test body that provides scores for new models entering the market depending on how much protection they offer to occupants, pedestrians and other road users when a collision occurs. 

But Which? tests have found it could have a major tech flaw.

During the course of testing, lab testers noticed ‘unusual behaviour’ with the vehicle’s lane-departure warning and lane-keep assistance systems, which it warns could be a ‘potentially significant issue’.

‘On one occasion where the tester drove on a narrow country road and had to pass another car travelling in the opposite direction, the MG4’s lane-keep assistance system steered away from the nearside edge of the road and towards the centre – and the other vehicle,’ Which? said.

The tester was forced to manually intervene to prevent the MG4 veering too close to the car travelling in the opposite direction, it claimed.

The EV in question is MG’s 4 EV, which has been widely regarded as one of the best electric cars on the market currently. Last year, 21,715 were registered in Britain

While driving on a narrow country road with another car travelling in the opposite direction, the MG4’s lane-keep assistance system steered away from the nearside edge of the road and towards the centre – and the other vehicle, the consumer group said

On another occasion, this time on a wider road with a clearly defined centre line (similar to the one pictured), the lane-keep assistance technology twice decided that the car had left its intended lane and pulled it onto the wrong side of the road 

Which? said the tester at the time had to use a ‘sufficient amount of force’ on the steering wheel to pull the car back onto the correct side of the road

‘On another occasion, this time on a wider road with a clearly defined centre line, the lane-keep assistance technology twice decided that the car had left its intended lane and pulled it onto the wrong side of the road. 

‘Using a sufficient amount of force, our tester had to manually steer the car back,’ Which? says.

All three incidents were noticed during the course of testing that it carries out on around 100 of the latest new cars coming to market – not just EVs but petrol, diesel and hybrid models too.

These tests are carried out public roads instead of controlled lab conditions, and Which? says none of the issues experienced by the testers could be repeated in subsequent road tests. 

Testers said they had not seen behaviour before like they had experienced with the MG4 EV, which it says were ‘significant enough for us to investigate further’.

All three incidents were noticed during the course of testing that it carries out on around 100 of the latest new cars coming to market – not just EVs but petrol, diesel and hybrid models too

Testers said they had not seen behaviour before like they had experienced with the MG4 EV, which it says were ‘significant enough for us to investigate further’

When asked by Which?, Euro NCAP didn’t comment specifically on the MG4 but said: ‘Vehicle manufacturers have a responsibility to ensure that the vehicle performance seen on a test track is also reflected in on-road driving.

‘In recent years, we have seen that not all manufacturers put in the same amount of effort on road evaluation of their systems. Therefore, Euro NCAP have already made a first step in 2024 regarding acceptance requirements for lane-keeping systems.

‘This will be followed by on-road evaluation procedures for 2026 and beyond, which Euro NCAP is currently developing.’

What has MG said about the potential glitch? 

This is Money contacted MG Motor UK for comment on the problems raised by Which?, though was told that the company had no further comment to those provided to the watchdog itself.  

In this statement it said: ‘We are aware of some inconsistencies relating to the lane-departure warning system which can make the system oversensitive under certain conditions.

‘We have been working on a continuous improvement programme with the supplier and the relevant regulatory authorities.

‘This has resulted in an improved calibration of the ADAS [Advanced Driver Assistance Systems], which we are close to having approved. Once this has been completed, we will implement it as a full software upgrade at no expense to the customer.’

MG says it is aware of a potential issue and is currently developing an improved calibration of the lane keep assistance system, which it says is ‘close to having approved’. Once complete, customers will be able to access it via a free software update, it says

An MG spokesperson said that customers who find the function oversensitive can turn it off via the touchscreen menu, but caveated the suggestion by saying ‘we would reiterate that we have had no safety-related reports from customers’

Do you own an MG4 EV? 

Which? asked MG Motor UK what actions owners of existing MG4 EVs should do if they experience a similar behaviour from the car to that recorded by its test team.

A spokesperson said: ‘If a customer does feel this function is oversensitive in its current calibration it can be turned off via the touchscreen menu, but we would reiterate that we have had no safety-related reports from customers. 

‘A software solution to resolve the issue is very near to completion and the MG dealer network will perform the work at no cost to the customer.’

Do you own an MG4 EV and have experienced the same problem? Then get in touch by emailing rob.hull@thisismoney.co.uk