Safety regulator looks at allegation that Tesla failed to disclose battery flaw

The National Highway Traffic Safety Administration says it’s received a petition calling for an investigation of certain Tesla Inc. electric cars and is evaluating the complaint, according to a notice posted on the regulator’s website.

The petition, filed by a law firm representing Tesla drivers, alleges that Tesla updated battery management software in response to a potential defect that could lead to battery fires, according to the NHTSA notice. The law firm claimed that Tesla should have notified NHTSA of the potential defect and conducted a recall.

NHTSA hasn’t opened a defect investigation but is reviewing whether to do so.

NHTSA said it would evaluate the allegations and decide whether to grant or deny the petition. If NHTSA grants it, the agency would launch a preliminary defect investigation into the issue under agency processes.

The petition was filed by the Law Offices of Edward C. Chen, a California law firm representing a number of Tesla drivers in the U.S. who’ve experienced “a significant amount of range loss” after the software updates, including one driver who sued Tesla over the issue in August, according to the petition.

The firm says drivers saw the range of their Teslas fall by 25 miles or more after Tesla released two battery management software updates beginning in May 2019. NHTSA estimates 2,000 Model S and Model X vehicles were affected.

Tesla representatives didn’t immediately reply to an email seeking comment.

Tesla released the software after a Model S caught fire in a Hong Kong parking lot in May, saying at the time that the update was a precautionary measure to protect the vehicle’s battery pack. The August lawsuit claims those software updates limited the battery’s capacity, decreasing the amount of energy it could store and how quickly it could be charged.

Separately, NHTSA and the National Transportation Safety Board are evaluating a number battery fires in Tesla vehicles.