California’s Attorney General (AG) is currently conducting an investigation into Tesla. The investigation centers on Autopilot safety concerns and allegations of false advertising for the Full Self Driving (FSD) feature.

Autopilot is a driver assistance feature that helps drivers to safely change lanes, steer around curves, and stop their cars. The Autopilot feature is included on all new Tesla vehicles. Meanwhile, FSD is an optional technology that allows Tesla vehicles to fully drive themselves.

California resident Greg Wester triggered the AG investigation when he filed a complaint with the Federal Trade Commission (FTC) in August 2022. Wester owns a 2018 Tesla Model 3. He reported experiencing “phantom braking,” an abrupt and unexplained automatic braking by the car, while driving his Tesla on the highway.

Tesla customers have raised the issue of phantom braking with federal agencies for years. Phantom braking puts drivers at risk of rear-end collisions and other dangers.

Wester’s FTC complaint also mentioned issues with FSD. Wester spent thousands of dollars to get FSD capability for his Tesla. However, the purchased FSD product turned out to be a driver monitoring system with partial autonomy rather than full autonomy.

Tesla CEO Elon Musk had previously promised customers that the company’s vehicles would eventually become fully autonomous through over-the-air software updates. However, as of yet, Tesla has not delivered a fully self-driving car. It continues to sell “level 2” systems, which require a vigilant driver ready to take control at any time.

Tesla and the California attorney general’s office did not respond to CNBC’s requests for comment. The FTC also declined to provide any remarks.

Although Tesla has previously disclosed requests for documents related to the Autopilot and FSD features, it had not revealed the ongoing investigation by the California AG.

The news that the California AG is investigating Tesla should be concerning to Elon Musk. California is Tesla’s largest US market and is home to Tesla’s first vehicle assembly plant.

The AG investigation is an escalation of an earlier investigation launched by the California Department of Motor Vehicles (DMV). In July 2022, California’s DMV formally accused Tesla of dishonestly marketing its Autopilot and FSD technology.