DTC B1855/63: Short in Rear Side Squib LH Circuit; DTC B1856/63: Open in Rear Side Squib LH Circuit; DTC B1857/63: Short to GND in Rear Side Squib LH Circuit; DTC B1858/63: Short to B+ in Rear Side Squib LH 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.