DTC B1860/64: Short in Driver Side Knee Airbag Squib Circuit; DTC B1861/64: Open in Driver Side Knee Airbag Squib Circuit; DTC B1862/64: Short to GND in Driver Side Knee Airbag Squib Circuit; DTC B1863/64: Short to B+ in Driver Side Knee Airbag Squib Circuit [08/2013 - ]: Wiring Diagram
WARNING: This page is about a different car, the 2014 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.