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Home >> Ford >> 2002 >> Taurus SES, 3.0 S >> Repair and Diagnosis >> External Pages >> Different car >> Section 219 (Supplemental Inflatable Restraint System) >> Diagnostic Tests >> Test B: Air Bag Warning Light Circuit Open Or Short To Ground (DTC B1869) >> Possible Causes

Possible Causes

WARNING: This page is about a different car, the 2003 Mercury Sable and 2003 Ford Taurus. However, it is still accessible from the selected car via links, so may be relevant.

AIR BAG warning light inoperative condition could be caused by damaged wiring, terminals or connectors, faulty RCM, faulty AIR BAG warning light bulb or instrument cluster internal malfunction.

  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 Diagnostic Trouble Codes (DTCs). See RETRIEVING FAULT CODES  under DIAGNOSTICS. Perform on-demand self-test. See ON-DEMAND SELF-TEST  under DIAGNOSTICS. If DTC B1869 was retrieved during on-demand self-test and AIR BAG warning light does not illuminate, go to next step. If DTC B1869 was retrieved during on-demand self-test and AIR BAG warning light does illuminate, go to step  8 . If DTC B1869 was not retrieved, fault is intermittent. Go to step  10 .

  2. Check circuit No. 640

    Turn ignition switch to OFF position. Disable air bag system. Access instrument cluster and disconnect harness connector C220B. See INSTRUMENT CLUSTER  under REMOVAL & INSTALLATION. Turn ignition switch to RUN position. Measure voltage between ground and harness side of instrument cluster connector C220B, terminal No. 10 (Red/Yellow wire, circuit No. 640). See Figure . If voltage is 9-16 volts, go to next step. If voltage is not 9-16 volts, repair open in Red/Yellow wire. See WIRING DIAGRAMS  . Go to step  11 .

  3. Check instrument cluster AIR BAG warning light circuit for open

    Turn ignition switch to OFF position. Measure resistance between component side of instrument cluster connector C220B, terminals No. 10 and 11. If resistance is less than 500 ohms, go to step  6 . If resistance is more than 500 ohms, go to next step.

  4. Visually check AIR BAG warning light bulb

    Remove AIR BAG warning light bulb. Visually inspect light bulb. If bulb is damaged or the filament is open, replace bulb and go to next step. If bulb is okay, replace instrument cluster. Go to step  11 .

  5. Check instrument cluster AIR BAG warning light circuits

    Measure resistance between component side of instrument cluster connector C220B, terminals No. 10 and 11. If resistance is less than 500 ohms, fault is corrected. Go to step  11 . If resistance is more than 500 ohms, replace instrument cluster. Go to step  11 .

  6. Check circuit No. 608 for open

    Turn ignition switch to OFF position. Disable air bag system. See DISABLING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Access RCM and disconnect harness connector C310A. See RESTRAINTS CONTROL MODULE (RCM)  under REMOVAL & INSTALLATION. Measure resistance between harness side of instrument cluster connector C220B, terminal No. 11 and harness side of RCM connector C310A, terminal No. 15 (Black/Yellow wire, circuit No. 608). See Figure & Figure . If resistance is less than 5 ohms, go to next step. If resistance is more than 5 ohms, repair open in Black/Yellow wire. See WIRING DIAGRAMS  . Go to step  11 .
    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.

  7. Confirm RCM fault

    Reconnect RCM and instrument cluster connectors. Perform on-demand self-test. If DTC B1869 was retrieved during on-demand self-test, replace RCM. Go to step  11 . If DTC B1869 was not retrieved during on-demand self-test, go to step  11

  8. Check circuit No. 608 for short to ground

    Turn ignition switch to OFF position. Access instrument cluster and disconnect harness connector C220B. See INSTRUMENT CLUSTER  under REMOVAL & INSTALLATION. Measure resistance between ground and harness side of instrument cluster connector C220B, terminal No. 11 (Black/Yellow wire, circuit No. 608). See Figure . If resistance is less than one megohm, go to next step. If resistance is more than one megohm, replace instrument cluster. Go to step  11 .

  9. Check RCM for short to ground

    Access RCM and disconnect harness connector C310A. See RESTRAINTS CONTROL MODULE (RCM)  under REMOVAL & INSTALLATION. Measure resistance between ground and component side of RCM connector C310A, terminal No. 15. See Figure . If resistance is less than one megohm, replace RCM. Go to step  11 . If resistance is more than one megohm, repair short to ground on Black/Yellow wire. Go to step  11 .

  10. Check for intermittent fault

    Disable air bag system. See DISABLING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Perform on-demand self-test. If DTC B1869 was retrieved during on-demand self-test, go to step  2 . If DTC B1869 was not retrieved during on-demand self-test, check for cause of intermittent short to ground or open 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.

  11. 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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