The National Highway Traffic Safety Administration asked Tesla this week to explain why the company did not issue a recall notice last month when it implemented a safety-related software update to its "Autopilot" program.
The NHTSA’s latest inquiry referenced Tesla’s update to some vehicle models that improved their ability to detect emergency vehicle lights in "low light conditions" while utilizing Autopilot. Federal regulators are currently probing Tesla’s semi-autonomous driving system, which automatically controls basic tasks, such as steering and acceleration, but requires human oversight.
"As Tesla is aware, the Safety Act imposes an obligation on manufacturers of motor vehicles and motor vehicle equipment to initiate a recall by notifying NHTSA when they determine vehicles or equipment they produced contain defects related to motor vehicle safety or do not comply with an applicable motor vehicle safety standard," an NHTSA official said in a letter addressed to Eddie Gates, Tesla’s director of field quality.
The letter noted that automakers are required to notify the NHTSA of a recall notice within five days after they identify a "safety defect or noncompliance" in their vehicles. The agency asked Tesla if it plans to file a recall notice for the software update or to provide a "technical and/or legal basis for declining to do so."
Tesla did not immediately respond to a request for comment.
In a separate letter, the NHTSA asked Tesla to provide details on its beta test for "Full Self-Driving" software, including the number of participants and information on non-disclosure agreements participants were asked to sign.
In August, the NHTSA opened an investigation into Tesla’s Autopilot function. The probe focuses on 12 crashes in which Tesla vehicles using Autopilot purportedly failed to detect emergency vehicles.
Tesla officials have maintained that the Autopilot system is safe.