Tesla boss Elon Musk has admitted there is a braking issue in its Model 3 cars but promised a firmware update to fix it "in the next few days".
The problems were flagged up in a
review of the electric car by US website Consumer Reports.
"Our testers found flaws - big flaws - such as long stopping distances in our emergency braking test and difficult-to-use controls," wrote Patrick Olsen.
Tesla had at first disputed the findings.
The reviewer said braking distances on average were 152ft (46m), adding that that "was far worse than any contemporary car we've tested".
In response, Tesla released a statement which read: "Tesla's own testing has found braking distances with an average of 133ft when conducting the 60-0 mph stops using the 18" Michelin all season tyre and as low as 126ft with all tyres currently available."
But later Mr Musk tweeted that the issue would be dealt with before the end of the week.