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) B1771 could be caused by a open, short, short to ground or short to battery in passenger-side seat belt buckle switch circuit, passenger-side seat belt buckle malfunction, occupant classification Electronic Control Unit (ECU) malfunction.
NOTE:
Diagnose DTC B1771 first when DTCs B1771 and B1795 are output simultaneously.
During testing, if DTCs other than DTC B1771 are displayed, disregard them.
If wire harness inspection is difficult to perform, remove right front seat mounting bolts to access area under seat cushion. Hold seat in such a way so it will not fall. Holding seat for prolonged periods of time may cause seat rail deformation. Hold seat only when necessary.
During testing, if DTCs other than DTC B1771 are displayed, disregard them.
If wire harness inspection is difficult to perform, remove right front seat mounting bolts to access area under seat cushion. Hold seat in such a way so it will not fall. Holding seat for prolonged periods of time may cause seat rail deformation. Hold seat only when necessary.