Possible Causes

A short to ground on left seat belt pretensioner circuit could be caused by short to ground on Light Green/Red wire, short to ground on Light Green/Black wire, short to ground in left seat belt pretensioner, or RCM internal fault.

1. Check for hard or intermittent DTCs
   
   Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). See USING SCAN TOOL  under DIAGNOSTICS. Turn ignition switch to RUN position. Retrieve and record any continuous DTCs. See RETRIEVING FAULT CODES  . Clear continuous DTCs. See CLEARING FAULT CODES  under DIAGNOSTICS. Perform on-demand self-test. See ON-DEMAND SELF-TEST  under DIAGNOSTICS. If DTC B1879 was retrieved during on-demand self-test, fault is hard. Go to next step. If DTC B1879 was not retrieved, fault is intermittent. Go to step  4 .
2. 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. If DTC B1879 was retrieved during on-demand self-test, go to next step. If DTC B1879 was not retrieved during on-demand self-test, replace left seat belt pretensioner. See SEAT BELT PRETENSIONERS  under REMOVAL & INSTALLATION. Go to step  5 .
3. Check left seat belt pretensioner circuits
   
   Turn ignition switch to OFF position. Disconnect negative battery cable. Access and disconnect RCM harness connector C2041A. See RESTRAINTS CONTROL MODULE (RCM)  under REMOVAL & INSTALLATION. Disconnect seat belt pretensioner simulator from left pretensioner harness connector. Turn ignition switch to RUN position. Measure resistance between ground and RCM harness connector C2041A, terminals No. 18 (Light Green/Red wire) and No. 22 (Light Green/Black wire) individually. See Figure . If resistance is less than 10 k/ohms at either terminal, repair short to ground in Light Green/Red or Light Green/Black wire (circuit No. 1079 or 1080). See WIRING DIAGRAMS  . Go to step  5 . If resistance is more than 10 k/ohms at both terminals, replace RCM. Go to step  5 .
4. Check for intermittent fault
   
   Refer to continuous DTCs recorded in step  1 . If DTC retrieved in step  1 was an intermittent fault, check for cause of intermittent short to ground on Light Green/Red or Light Green/Black wire (circuit No. 1079 or 1080). See WIRING DIAGRAMS  . Attempt to recreate fault by flexing wire harness and cycling ignition switch frequently. Repair any intermittent problems found. Go to next step. If DTC retrieved in step  1 was not an intermittent fault, go to next step.
5. Check for additional DTCs
   
   Refer to continuous DTCs recorded in step  1 . If any continuous DTCs were retrieved, go to diagnostic trouble code identification table for direction to appropriate test. See DIAGNOSTIC TROUBLE CODE IDENTIFICATION  table. DO NOT clear any DTCs until all DTCs have been resolved. If no DTCs were retrieved, reconnect air bag system. Activate air bag system. See ACTIVATING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Prove out system. See PROVE OUT SYSTEM  under DIAGNOSTICS. Clear all DTCs. See CLEARING FAULT CODES  under DIAGNOSTICS.