Possible Causes

A left seat belt buckle switch open circuit or short to battery fault could be caused by damaged wiring, terminals, connectors, faulty seat belt buckle switch or faulty RCM.

1. Check for hard or intermittent DTC
   
   Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). See USING SCAN TOOL  under DIAGNOSTICS. Turn ignition switch to ON position. Retrieve and record any continuous Diagnostic Trouble Codes (DTCs). See RETRIEVING FAULT CODES  under DIAGNOSTICS. Perform on-demand self-test. See ON-DEMAND SELF-TEST  under DIAGNOSTICS. If DTC B2691 was retrieved during on-demand self-test, fault is hard. Go to next step. If DTC B2691 was not retrieved, fault is intermittent. Go to step  7 .
2. Check for open between RCM and left front seat belt buckle switch
   
   Turn ignition switch to OFF position. Disable air bag system. See DISABLING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Access RCM and disconnect connector C310B. See RESTRAINTS CONTROL MODULE (RCM)  under REMOVAL & INSTALLATION. Disconnect left front seat belt buckle switch connector. Measure resistance in Brown/Light Blue wire (circuit No. 85) between harness side of RCM connector C310B, terminal No. 25 and harness side of left seat belt buckle switch connector. See Figure . See WIRING DIAGRAMS  . If resistance is less than 0.5 ohm, go to next step. If resistance is more than 0.5 ohm, repair open in Brown/Light Blue wire. Go to step  8 .
3. Check circuit for open
   
   Measure resistance in Black/Orange wire (circuit No. 649) between ground and harness side of left seat belt buckle switch connector. If resistance is less than 0.5 ohm, go to next step. If resistance is more than 0.5 ohm, repair open in Black/Orange wire. Go to step  8 .
4. Check circuit for short to voltage
   
   Turn ignition switch to ON position. Measure voltage in Brown/Light Blue wire between ground and harness side of left seat belt buckle switch connector. If voltage is less than 0.2 volt, go to next step. If voltage is more than 0.2 volt, repair short to voltage in Brown/Light Blue wire. Go to step  8 .
5. Check seat belt buckle switch
   
   Turn ignition switch in OFF position. Connect connector C310B. Install known-good seat belt buckle switch. See SEAT BELT BUCKLE PRETENSIONER/SWITCH ASSEMBLY  under REMOVAL & INSTALLATION. Connect negative battery cable. Perform on-demand self-test. If DTC B2691 was retrieved during on-demand self-test, go to next step. If DTC B2691 was not retrieved, fault is corrected. Go to step  8 .
   NOTE: Ensure all air bag system simulators, sensor electrical connectors and RCM electrical connectors are connected prior to carrying out on-demand self-test or erroneous faults may be set.
6. Confirm RCM fault
   
   Turn ignition switch to OFF position. Install original seat belt buckle switch. Perform on-demand-self-test. If DTC B2691 was retrieved during on-demand self-test, replace RCM. Go to step  8 . If DTC B2691 was not retrieved during on-demand self-test, fault is corrected. Go to step  8 .
7. Check for intermittent DTC
   
   Turn ignition switch to OFF position. Disable air bag system. See DISABLING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Perform on-demand self-test. If DTC B2691 was retrieved during on-demand self-test, go to step  2 . If DTC B2691 was not retrieved during on-demand self-test, check for cause of intermittent fault. Attempt to recreate fault by flexing wire harness and cycling ignition switch frequently. Repair any intermittent problems found. Go to next step.
8. 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. Clear all DTCs. See CLEARING FAULT CODES  under DIAGNOSTICS.