Possible Causes
WARNING: This page is about a different car, the 2004 Toyota Matrix and 2004 Toyota Corolla. However, it is still accessible from the selected car via links, so may be relevant.
Diagnostic Trouble Code (DTC) 27/B0126 or B0127 could be caused by an open, short, short to ground or short to battery in left front seat belt buckle switch circuit, left front seat belt buckle assembly malfunction or air bag sensor assembly malfunction.
NOTE:
During testing, if DTCs other than DTC 27/B0126 & B0127 are displayed, disregard them.