The saga began in December when GM announced it would recall about 550,000 pickups and Cadillac CT6 sedans globally to fix a software error that can disable the electronic stability control and antilock brakes. If those features don't work, it can increase the risk of a crash.
The new software was installed in about 162,000 vehicles, but GM started getting reports that it was causing other problems, according to documents GM filed with the U.S. National Highway Traffic Safety Administration.
If the vehicles are started remotely using a GM mobile phone app or the driver gets in the vehicle and waits five or more minutes before starting it, the software could disable the electronic power brake assist system and turn on several dashboard warning lights, the documents said.
GM spokesman Dan Flores said the new problem showed up in about 1% of the vehicles that received the new software, which was corrected in January. The second problem didn't show up in any Cadillac vehicles, Flores said.
The company has no reports of any crashes or injuries from the problem, Flores said. Owners in the original recall will get letters notifying them to bring their vehicles to dealers for a software update. Those that received the faulty update will get a second letter starting Feb. 10.