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Home >> Ford >> 2001 >> Mustang Base, 2D Convertible, Automatic >> Repair and Diagnosis (Single Page) >> Restraints >> Air Bag, SRS >> Supplemental Inflatable Restraint System >> Diagnostic Tests >> Test P: Air Bag Warning Light Inoperative (DTC B1869) >> Possible Causes

Possible Causes

AIR BAG warning light inoperative condition could be caused by damaged Black-Yellow wire (circuit 608), damaged or burned out bulb, instrument cluster malfunction or an RCM internal fault.

  1. Check for hard or intermittent DTC

    Ensure ignition is off. 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 DIAGNOSTIC TROUBLE CODES (DTCS)  under DIAGNOSTICS. Perform on-demand self-test. See ON-DEMAND SELF-TEST  under DIAGNOSTICS. If DTC B1869 was retrieved during on-demand self-test, fault is hard. Go to next step. If DTC B1869 was not retrieved, fault is intermittent. Go to step  5 .

  2. Check RCM

    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. See RESTRAINTS CONTROL MODULE (RCM)  under REMOVAL & INSTALLATION. Measure resistance between ground and RCM pin No. 20. (measure at component) See Fig 1 . If resistance is more than 10 ohms, go to next step. If resistance is less than 10 ohms, replace RCM. Go to step  6 .

  3. Check circuit for open

    Turn ignition switch to OFF position. Access and disconnect instrument cluster connector C250. See INSTRUMENT CLUSTER  under REMOVAL & INSTALLATION. Measure resistance between ground and instrument cluster connector C250, terminal No. 12 (Black-Yellow wire). See Figure . If resistance is less than 100 ohms, repair short to ground in Black-Yellow wire (circuit 608). See WIRING DIAGRAMS  . Go to step  6 . If resistance is more than 100 ohms, go to next step.

  4. Check circuit for open

    Measure resistance of Black-Yellow wire between RCM harness connector terminal No. 20 and instrument cluster connector C276, terminal No. 12. See Figure & Figure . If resistance is less than 10 ohms, diagnose and repair instrument cluster as necessary. Go to step  6 . If resistance is more than 10 ohms, repair open in Black-White wire. Go to step  6 .

  5. Check for intermittent fault

    Refer to continuous DTCs recorded in step  1 . If DTC retrieved in step  1 was a intermittent fault, check for cause of intermittent short to ground or open on Black-Yellow wire (circuit 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. If DTC retrieved in step  1 was not a intermittent fault, go to next step.

  6. 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 appropriate test. See DIAGNOSTIC TROUBLE CODE (DTC) 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 DIAGNOSTIC TROUBLE CODES (DTCS)  under DIAGNOSTICS.
    Fig 1: Identifying Restraints Control Module Pin No. 20
    G99E00097Courtesy of FORD MOTOR CO.
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