Possible Causes
WARNING: This page is about a different car, the 2002 Toyota Highlander. However, it is still accessible from the selected car via links, so may be relevant.
DTC 74/B0136 could be caused by an open in circuit PL+ (Yellow/Black wire) and circuit PL- (Yellow wire) in left seat belt pretensioner squib circuit, left seat belt pretensioner squib malfunction or air bag sensor assembly malfunction.
NOTE:
During testing, if DTCs other than DTC 74/B0136 are displayed, disregard them.