Possible Causes

Left seat belt pretensioner circuit short to ground could be caused by short to ground in wiring harness, low resistance in left seat belt pretensioner, or damaged or inoperative RCM.

1. Check left seat belt pretensioner
   
   Turn ignition off. 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 B1879 is retrieved, go to next step. If DTC B1879 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. Repeat on-demand self-test.
2. Check left seat belt pretensioner circuits
   
   Turn ignition off. Access RCM and disconnect harness connector C423. See RESTRAINTS CONTROL MODULE  under REMOVAL & INSTALLATION. Disconnect left seat belt pretensioner simulator. Turn ignition switch to RUN position. Measure resistance between ground and RCM harness connector C423, terminal No. 11 (Green/Blue wire). See Figure. Measure resistance between ground and RCM harness connector C423, terminal No. 12 (Black/Blue wire). If resistance is more than 10 k/ohms, replace RCM. Activate air bag system. See ACTIVATING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Clear DTCs. Repeat on-demand self-test. If resistance is less than 10 k/ohms, repair short to ground in Green/Blue or Black/Blue wire. Activate air bag system. See ACTIVATING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Clear DTCs. Repeat on-demand self-test.