The buggy update - which was delivered via a wireless transmission - is causing affected vehicles' infotainments systems to stop working.
This prevents drivers from getting navigation directions, climate controls and digital radio.
The Toyota division has acknowledged the problem and said owners needed to bring their cars in.
"Errant data broadcast by our traffic and weather data service provider was not handled as expected by the microcomputer in the vehicle navigation head unit (centre display) of 2014-16 Model Year Lexus vehicles and 2016 Model Year Toyota Land Cruiser," a spokeswoman explained.
"In some situations, this issue can cause the head unit to restart repeatedly, affecting operation of the navigation system (if equipped), audio and climate control features.  The data suspected to be the source of the error was corrected last night."
The firm said "many" vehicles had been affected.
It confirmed the problem only affected US-based drivers who subscribed to Enform, a data-transmitting service not available in Europe.
Several motorists have posted videos showing the cars' screens booting up, flashing purple and then crashing. The fault repeats whether the vehicles are stationary or moving.
At least one car owner believed their car had been "hacked".
Some owners have reported that when they disconnected their car battery, it reset the unit and made it work again. But others have said this only provides a temporary fix as the problem returns several hours later.
"The correction is a forced reset and clearing of the errant data from the system," Lexus later explained.
"Toyota and Lexus owners experiencing these issues should visit their dealer for a complimentary system reset and a confirmation of the system.  We regret any inconvenience."
The issue threatens to tarnish Lexus's reputation. It had been ranked as the "most reliable" car brand in Consumer Reports' survey of the automobile industry last year.
"Lexus has an excellent reputation for reliability, but these days that's not just about having trustworthy mechanical parts but its also electronics and software," commented Prof David Bailey from Aston Business School.
"There are typically more lines of code in a car than an aircraft, and you only have to get one part wrong for it to cause these types of problems."
A faulty data broadcast is causing problems for Lexus car owners in the US.