My 2013 Lexus LS460 with ~50,000mi had its brake actuator failed (C1391 - Leak in the accumulator). A month prior to code C1391 being triggered, the vehicle experienced inconsistent braking pressure with severe brake pedal modulation required to stop the vehicle. Traveling at speeds under 30 MPH the vehicle would intermittently hesitate to stop. Moreover, a squawk noise was present when depressing the brake pedal. Code C1391 was triggered on 11/18/2021. Upon contacting Lexus dealers and national customer service (Guest incident #211121-000001) to repair the part under warranty, Lexus denied warranty. Inquiry was also made for Lexus dealers and Lexus customer service as to the correct brake actuator part number required for replacement. Both Lexus dealers and national customer service provided the wrong/superseded replacement part number (i.e., part 44050-50110). Below is the customer's research model LS460 brake actuators: -Per 2016 ZLG warranty: 2007-2012 LS460 came with part 44050-50090, 44050-50130 to be replaced by 04003-45450 actuator. -Per 2016 LSB-0047-19: 2013-2017 LS460 came with part 44510-50070 and 44050-50110 to be replaced with the same model 44050-50110 actuator for brake squawk noise. -Per 2019 LSB-0047-19: 2007-2017 LS460 came with part 44050-50110, 44050-50130, 44050-50150, 44050-50170, 44050-50090 to be replaced with 44050-50170 if repairs fail to remedy the brake squawk noise. It appears Lexus has attempted to revised the brake actuator various times to arrive at part 44050-50170, for which continues to fail. It also appears many superseded units are still being sold as replacements for failed actuators online through Lexus dealerships and Lexus authorized retailers. It must also be noted that a failing brake actuator (even prior to code C1391) will cause the brake booster pump to prematurely fail as the brake booster has to constantly pressurize the system causing it to overheat. Both repairs are urgent costing $3000-3500 each.
NHTSA ODI 11444362