Chasity Glisson, 29, was found dead in her Boca Raton townhouse and boyfriend Timothy Maddock nearly dead on Aug. 25, with her keyless Lexus running in the garage.
Maddock and Glisson's mother, Kimberlin Nickles, filed a wrongful death suit in Fort Lauderdale Tuesday.
Their attorney, Eric Rose, told WPTV, West Palm Beach: "We believe there should be some type of safety features that prevent something like this from happening. There may be personal responsibility here for people, but that responsibility shouldn't result in someone's death."
Keyless ignition systems let drivers start and stop their car by pushing a button. They have been blamed for several deaths nationwide, and this suit is at least the second against Toyota.
The plaintiffs also are suing Marbella Premium Apartments over its ventilation system.
The apartment management says it will cooperate fully with any investigation. A Toyota spokesman declined comment on the suit, saying the company had not seen it yet.