Technical Service Bulletin L-SB-0001-21 Rev — 2017 LEXUS GS 350

TSB: Some 2013 ? 2017 model year Lexus vehicles may exhibit one of the following HVAC conditions. ?Uneven temperature or air flow between the vents. ?Little or no air flow from the vent(s). ?Improper MODE control function. Additionally, some vehicles may store one or more of the following HVAC servo Diagnostic Trouble Codes (DTCs). ?B1441 ? Air Mix Damper Control Servo Motor Circuit (Front Passenger Side Lower Air Mix). ?B1442 ? Air Inlet Damper Control Servo Motor Circuit. ?B1443 ? Air Outlet Damper Control Servo Motor Circuit. ?B1446 ? Air Mix Damper Control Servo Motor Circuit (Driver Side Lower Air Mix). ?B1447 ? Rear Air Mix Damper Control Servo Motor Circuit. ?B1448 ? Passenger Side Face Servo Motor Circuit. ?B1449 ? Rear Air Outlet Damper Control Servo Motor Circuit. ?B1453 ? Driver Side Air Outlet Damper COOL Control Servo Motor Circuit. ?B1454 ? Passenger Side Air Outlet Damper COOL Control Servo Motor Circuit. ?B1455 ? Driver Side Air Outlet Damper FOOT/DEF Control Servo Motor Circuit. Follow the procedures in this bulletin to address this condition.