Possible Causes
WARNING: This page is about a different car, the 2004 Lincoln LS. However, it is still accessible from the selected car via links, so may be relevant.
Air bag tone warning indicator circuit shorted to battery could be caused by damaged wiring harness, terminals or connectors, faulty instrument cluster or faulty RCM.
- 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 B1891 was retrieved during on-demand self-test, fault is hard. Go to next step. If DTC B1891 was not retrieved, fault is intermittent. Go to step 4 . - Check air bag tone warning indicator circuit for short to battery
Turn ignition switch to OFF position. Disable air bag system. See DISABLING SYSTEM under DISABLING & ACTIVATING AIR BAG SYSTEM. Access RCM and disconnect connector C310A. See RESTRAINTS CONTROL MODULE (RCM) under REMOVAL & INSTALLATION. Access instrument cluster and disconnect harness connector C220A. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. Connect negative battery cable. Turn ignition switch to ON position. Measure voltage between ground and harness side of RCM connector C310A, terminal No. 22 (White/Black wire, circuit No. 8-GE52). See Figure . If voltage is less than 0.2 volt, go to next step. If voltage is more than 0.2 volt, repair short to battery voltage in White/Black wire. See WIRING DIAGRAMS . Go to step 5 .NOTE: DTC B1892 should be retrieved when carrying out on-demand self-test in following step, due to open circuit in White/Black wire. DTC B1891 should not be retrieved. - Check air bag tone warning indicator circuit
Turn ignition switch to OFF position. Connect connector C310A. Connect negative battery cable. Turn ignition switch to ON position. Perform on-demand self-test. If DTC B1891 was retrieved during on-demand self-test, replace RCM. Go to step 5 . If DTC B1891 was not retrieved during on-demand self-test, replace instrument cluster. Go to step 5 . - Check for intermittent fault
Disable air bag system. See DISABLING SYSTEM under DISABLING & ACTIVATING AIR BAG SYSTEM. Perform on-demand self-test. If DTC B1891 was retrieved during on-demand self-test, go to step 2 . If DTC B1891 was not retrieved during on-demand self-test, check for cause of intermittent short to battery in White/Black wire. 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. - 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.