Tesla Inc's (TSLA) - Get Report Autopilot system may be under increased scrutiny, but it still has the potential to get investors excited. 

The electric carmaker's stock jumped close to 5% on Monday after Musk surprisingly disclosed in a tweet on Sunday that "full self-driving features" would be rolled out this summer via a software update to Autopilot, Tesla's driver-assistance system. The update, Version 9 of Autopilot, is expected in August.

The revelation came via a Twitter reply to an Autopilot driver who asked about a lane-merging problem in the current software. Musk also responded that the issue in question would be fully fixed in the August update.

Musk didn't elaborate further on what "full self-driving" features would entail in the August update, and didn't respond to requests for clarification on what level of autonomy Version 9 of Autopilot would support. 

Still, Musk's disclosure comes at a fraught time for the Autopilot system. Autopilot continues to face criticism following a fatal crash in March, in which a man driving a 2017 Model X using Autopilot collided with a barrier near Mountain View, Calif. after taking his hands off the wheel for six seconds. It was the second fatal crash linked to Tesla's Autopilot feature, among several other reported collisions and near-misses involving the feature.

Last week, a consumer advocacy group urged Tesla to fix flaws in Autopilot after a government report found that the system issued alerts for the driver in the March crash to place his hands back on the wheel, but that the last alert was issued 15 minutes before the crash.

The crash "demonstrates that Tesla's system can't dependably navigate common road situations on its own, and fails to keep the driver engaged exactly when it is needed most," said Consumers Union director David Friedman last week.

Despite the scrutiny, Tesla appears to be charging ahead with self-driving projects and in bringing its Autopilot system to more drivers more aggressively. At the shareholder meeting last week, Musk said that Tesla would "hopefully" offer a free trial of the company's autopilot technology next month. The system currently costs $5,000 extra for new Tesla owners.

Since the shareholder meeting last week, Tesla share have been on a strong upward climb.