Possible Causes
WARNING: This page is about a different car, the 2004 Lexus ES 330. However, it is still accessible from the selected car via links, so may be relevant.
Diagnostic Trouble Code (DTC) B1787 could be caused by seat adjuster frame malfunction, occupant classification ECU malfunction or occupant classification left rear sensor detected large load.
NOTE:
During testing, if DTCs other than DTC B1787 are displayed, disregard them.