When Consumer Reports reviewed Tesla’s first mass-market electric car, the Model 3, it concluded that it couldn’t recommend the car to its readers because of “big flaws,” including long stopping distances when braking at high speed.

Within days, Tesla beamed a wireless software update to the Model 3s on the road that improved their braking, and the impact was swift. After testing the car again, Consumer Reports reversed the verdict on Wednesday, only nine days after its original report was published, and gave the car a “recommended” rating.

“To see something updated that quickly is quite remarkable,” said Jake Fisher, the magazine’s director of auto testing. Other manufacturers have made software fixes to correct issues that Consumer Reports has identified, but owners then have to take their cars to dealers to have the update installed.

Tesla’s ability to update its cars in much the same way that Apple issues software updates for iPhones is a competitive advantage, Mr. Fisher said. “We’ve never seen a manufacturer do this in the course of a week,” he added.