Tesla said its "Full Self-Driving" feature might be delayed, according to a memo seen by Reuters.
Elon Musk has previously said he was "highly confident" that FSD could be achieved this year.
The FSD feature, currently a $10,000 add-on, has proved dangerous for some drivers.
Tesla on Thursday told a California regulator that it might not have its "Full Self-Driving" (FSD) technology ready by the end of the year, according to a memo by the California Department of Motor Vehicles (DMV) seen by Reuters.
In the carmaker's January earnings call, CEO Elon Musk said he was "highly confident the car will be able to drive itself with reliability in excess of human this year."
There are six levels of autonomous technology in vehicles which range from level zero (fully manual) to level five (fully autonomous).
"Tesla indicated that Elon is extrapolating on the rates of improvement when speaking about L5 capabilities. Tesla couldn't say if the rate of improvement would make it to L5 by end of calendar year," the California DMV said in the memo.
The carmaker "indicated that they are still firmly in L2," the memo said. Level two means the car is semi-autonomous and needs supervision by a human driver.
"As Tesla is aware, the public's misunderstanding about the limits of the technology and its misuse can have tragic consequences," the memo said.
Tesla didn't immediately respond to Insider's request for comment.
The FSD feature, currently a $10,000 add-on, has proved dangerous for some drivers. Videos show how Teslas with FSD switched on have nearly crashed on public roads.
In April, a Tesla ran off the road and killed the two people in it outside of Houston. The authorities said no one was driving the car but Musk denied the car was operating under Autopilot.
FSD is a more advanced version of Tesla's Autopilot - the company's standard driver-assistance software, which uses sensors and cameras to ensure the car stays in its lane and keeps up with highway traffic. The mode, which is in beta testing, builds on the Autopilot feature to make the car self-park, recognize traffic light and stop signs, and take highway ramps and exits.
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