Possible Causes

A left seat belt pretensioner circuit shorted to battery could be caused by a short to battery on Green-Blue wire (circuit 15S-JA33), a short to battery on Black-Blue wire (circuit 91S-JA33), a short to battery in left seat belt pretensioner or an internal RCM fault.

1. Check left seat belt pretensioner
   
   Turn ignition switch to OFF position. Disable air bag system. See DISABLING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Turn ignition switch to RUN position. Perform on-demand self-test. See ON-DEMAND SELF-TEST  under DIAGNOSTICS. If DTC B1878 is retrieved, go to next step. If DTC B1878 is not retrieved, replace left seat belt pretensioner. See SEAT BELT PRETENSIONER  under REMOVAL & INSTALLATION. Activate air bag system. See ACTIVATING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Clear DTCs. See CLEARING FAULT CODES  under DIAGNOSTICS. Repeat on-demand self-test.
2. Check left seat belt pretensioner circuits
   
   Turn ignition switch to OFF position. Access RCM and disconnect harness connector C423. See RESTRAINTS CONTROL MODULE (RCM)  under REMOVAL & INSTALLATION. Disconnect left seat belt pretensioner simulator. Turn ignition switch to RUN position. Measure voltage between ground and RCM harness connector C423, terminal No. 11 (Green-Blue wire). See Figure. Measure voltage between ground and RCM harness connector C423, terminal No. 12 (Black-Blue wire). If any voltage is present, repair Green-Blue or Black-Blue wire as necessary. See WIRING DIAGRAMS . Activate air bag system. Clear DTCs. Repeat on-demand self-test. If no voltage is present, replace RCM. Activate air bag system. Clear DTCs. Repeat on-demand self-test.