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Home >> Ford >> 2002 >> Crown Victoria Base, 4.6 9 >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Supplemental Inflatable Restraint System >> Diagnostic Tests >> Test C: Air Bag Warning Light Circuit Short To Battery (DTC B1870) >> Possible Causes

Possible Causes

AIR BAG warning light short to battery could be caused by damaged wiring, terminals or connectors, or an 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 RUN position. Retrieve and record any continuous DTCs. See RETRIEVING FAULT CODES  under DIAGNOSTICS. Turn ignition switch to OFF position. Perform system operation check. See SYSTEM OPERATION CHECK  . Turn ignition switch to OFF position. Turn ignition switch to RUN position. Perform on-demand self-test. See ON-DEMAND SELF-TEST  under DIAGNOSTICS. If DTC B1870 was retrieved during on-demand self-test, fault is hard. Go to next step. If DTC B1870 was not retrieved, fault is intermittent. Go to step  4 .

  2. Check for AIR BAG warning light

    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  under REMOVAL & INSTALLATION. Turn ignition switch to RUN position. If AIR BAG warning light illuminates and stays illuminated, replace RCM. If AIR BAG warning light does not illuminate and stay illuminated, go to next step.

  3. Check for short to battery

    Turn ignition switch to OFF position. On models equipped with analog instrument cluster, disconnect instrument cluster connector C2220B. On models equipped with digital instrument cluster, disconnect warning light module connector C2222. On all models, reconnect RCM connector C310B. Turn ignition switch to RUN position. Perform on-demand self-test. If DTC B1870 was retrieved during on-demand self-test, repair short to battery in Black/Yellow wire (circuit No. 608). See WIRING DIAGRAMS  . Go to step  5 . If DTC B1870 was not retrieved, replace instrument cluster. Go to step  5 .

  4. Check for intermittent fault

    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 B1870 was retrieved during on-demand self-test, go to step  2 . If DTC B1870 was not retrieved during on-demand self-test, check for cause of intermittent short to battery in Black/Yellow wire (circuit No. 608). 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.

  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. Clear all DTCs. See CLEARING FAULT CODES  under DIAGNOSTICS.
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