Possible Causes

Left side air bag circuit short to ground could be caused by short to ground in wiring harness, low resistance in left side air bag module, or damaged or inoperative RCM.

1. Check left side air bag module
   
   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 B1993 is retrieved, go to next step. If DTC B1993 is not retrieved, replace left side air bag module. See SIDE AIR BAG MODULE  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 side air bag module circuits
   
   Turn ignition switch to OFF position. Access RCM and disconnect harness connector C423. See RESTRAINTS CONTROL MODULE (RCM)  under REMOVAL & INSTALLATION. Disconnect left side air bag module simulator. Measure resistance between ground and RCM harness connector C423, terminal No. 15 (Green-Black wire). See Figure. Measure resistance between ground and RCM harness connector C423, terminal No. 16 (Black-Green wire). If resistance is more than 10 k-ohms, replace RCM. Activate air bag system. Clear DTCs. Repeat on-demand self-test. If resistance is less than 10 k-ohms, repair short to ground in Green-Black and Black-Green wires. See WIRING DIAGRAMS . Activate air bag system. Clear DTCs. Repeat on-demand self-test.