Since Tesla began rolling out the latest version of Autopilot, many drivers have said the new software hasn't been so much an upgrade as a defeat of the system.
A report in Jalopnik Thursday cited several owners on Tesla user forums reporting that their cars' Autopilot systems no longer work since the update.
One user even said that his Model 3 displays a persistent message on the display screen that his car's automatic emergency braking, regenerative braking, and traction control aren't working, either.
While Autopilot so far is mostly a driver convenience feature, automatic emergency braking is a key safety feature available on a wide variety of modern cars.
The new software, version 8.1 2018.34.1, was supposed to make Autopilot more responsive, and some users have reported that it has made lane changes quicker and smoother.
The update has been rolling out over time. Some cars have had it for over a week, while some owners are just getting the software.
When owners having problems with the software have contacted Tesla, they report the company has said it is aware of the problem and is working on a fix. Some owners were promised the fix Wednesday. Others have been told Friday, others within two days.
It's not clear what cars are affected adversely and if any of those cars have received an effective fix.
Green Car Reports did not receive an immediate response when we reached out to Tesla to ask about the update.
The update has also generated complaints that the Autopilot system "nags" drivers more frequently to keep their hands on the steering wheel. At the same time, it reportedly makes it easier to dismiss those warnings by touching any button on the steering wheel without actually gripping the rim.
In a July call with investors, Tesla CEO Elon Musk said a new version 9 software update would start rolling out in August. So far, a few users have seen previews of version 9, which reportedly changes the vertical center control screen in the Model S and Model X to act more like the floating horizontal screen in the Model 3.
Musk said that the release of version 9 would begin to enable some of the first fully self-driving features in Autopilot. (The company has long sold Full Self-Driving Capability as an option, even though the features don't work yet, with buyers' knowledge that they will be enabled once the software is available. In return for pre-paying for the features, those buyers get a discount on the package.)
In a Twitter post on Sept. 5, Musk updated the version 9-release time frame, saying that early users may get updates in another week, and that it will roll out broadly by the end of September.