Tesla Inc. TSLA 2.81% was able to improve the braking distance of Model 3 cars by as much as 20 feet simply by wirelessly transmitting a software update to the vehicles—a significant achievement in the auto industry that shows how the company can boost performance without costly dealership repairs.
The improvement convinced Consumer Reports on Wednesday to recommend the Model 3 vehicle, reversing last week’s decision to withhold its influential endorsement partly because it deemed the car took too long to stop. The Consumer Reports seal of approval is sought after by the auto industry.
The Silicon Valley electric-car maker’s ability to change basic functions of the car through software updates via Wi-Fi or cellular signals puts it at the cutting edge of car development. Tesla has previously sent wireless updates to improve the driver’s assistance system called Autopilot, or to give a car greater acceleration. This latest change comes at a crucial time when Tesla is battling criticism of its newest vehicle.
“I’ve been at [Consumer Reports] for 19 years and tested more than 1,000 cars and I’ve never seen a car that could improve its track performance with an over-the-air update,” Jake Fisher, director of auto testing, said in Wednesday’s review.
The automotive industry has spent generations and fortunes requiring owners to bring vehicles to their service centers to make fixes. Last week, for example, Fiat Chrysler Automobiles NV recalled more than 5 million vehicles in the U.S. and Canada to fix a software glitch that could prevent drivers from canceling cruise control.
“Tesla has broken through a massive barrier that has haunted the auto industry since 1978,” when the first microprocessor was introduced in cars, said Dave Sullivan, an analyst for AutoPacific. “The ability to program modules over the air, such as the [anti-lock braking] module, represents a huge leap in keeping customers safe and reducing the number of unrepaired vehicles on the road.”
Other auto makers, including General Motors Co. , are rushing to develop similar over-the-air technology.
The lack of a recommendation from Consumer Reports would have threatened Tesla Chief Executive Elon Musk’s effort to bring electric cars to more mainstream customers. Tesla is struggling to ramp up production of the Model 3 while also facing questions about the safety of Autopilot after a few recent crashes involved the driver-assistance system. Tesla says Autopilot makes its vehicles safer than those without it.
Consumer Reports’ original review on May 21 raised new safety questions. The nonprofit organization said at the time that the Model 3 it purchased had a stopping distance of 152 feet from 60 miles an hour, “far worse than any contemporary car” and further than a full-size pickup.
In response, Mr. Musk promised last week on Twitter to make improvements to the brakes. On Saturday, he said, the software updates had begun rolling out, saying it should improve braking distance by about 20 feet during repeated heavy braking events. The software update changed the calibration of the anti-lock braking algorithm across variations in usage and environmental conditions, according to Tesla.
After the update, Consumer Reports said the sedan’s braking improved by 19 feet, boosting its score for the Model 3 to 77 points from 72. That pushed it two points over the minimum score for vehicles in that vehicle class to be recommended, according to Consumer Reports.
It had also in its original review dinged the car for difficult-to-use controls inside the vehicle, which has been designed without most of the traditional nobs, buttons and displays found in most cars and instead those are replaced with a flat screen in the center of the cockpit dash.
On Twitter Wednesday, Mr. Musk promised another software update was coming that aimed to improve the Model 3’s user interface.
Write to Tim Higgins at Tim.Higgins@WSJ.com
Appeared in the May 31, 2018, print edition as 'Tesla Brakes Better With Wireless Fix.'