There is a fix for the Jeep gear shift problem that killed actor Anton Yelchin. The problem is that most owners don't know it yet.

The problem is a confusing gear selector that could lead some drivers to believe that their vehicle is in Park when it isn't. A vehicle that isn't in Park can roll away and potentially injure or, in Yelchin's case, kill someone.

Weeks before Yelchin was killed Sunday, Fiat Chrysler had sent a written recall notice to owners warning them to make especially sure their cars are in Park before getting out of the vehicles. The notice also said they would get another letter later indicating when they could get their cars fixed.

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As of the day Yelchin was killed, Fiat Chrysler had not yet announced a fix for the problem.

But the automaker had already started sending a software patch to its dealers to fix vehicles like Yelchin's last week. It had planned to mail notices to owners alerting them to the availability of the fix on Friday, June 24.

It's common practice for automakers to wait until it ships parts or distributes software to fix a recall problem before notifying owners. That way, dealers are prepared to handle a flood of customers.

The electronic gear selector in vehicles like Yelchin's return to the upright position after a driver selects Drive or Park. In other words, it doesn't remain in the position the driver moves it to for parking. At a glance, that could make it difficult to be sure the vehicle was actually in Park.

The fix is only available for vehicles with either a 3.6-liter V6 or 5.7-liter V8 engine. But the software may not be immediately available for every variation of those vehicles.

Software for vehicles with other engines will be available at a later date.

"The software rollout is ongoing for all models and model years," Fiat Chrysler spokesman Eric Mayne said. "Customers with concerns may call the number on their recall notices."

Related: Why car gear shifters are so confusing

The software update will take a few hours to perform. After that the transmission will automatically shift to Park if the driver's side door is opened, the driver's seatbelt is unbuckled and the vehicle is stopped or moving slowly.

The vehicles involved in the gear selector recall are model-year 2012-2014 Dodge Charger and Chrysler 300 sedans, and model-year 2014-2015 Jeep Grand Cherokee SUVs.

Owners are advised to park their vehicles carefully. Drivers should always look to make sure the transmission is in Park before taking their foot off the brake and getting out. Drivers should also apply the parking brake every time they park.

Later versions of these vehicles have gear selectors that are easier to use.

Owners with questions can call the Fiat Chrysler recall line at 800-853-1403 or contact their dealer.