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Home >> Ford >> 2000 >> Excursion 7.3 F, 4WD >> Repair and Diagnosis (Single Page) >> Restraints >> Air Bag, SRS >> Supplemental Inflatable Restraint System - Excursion & Super Duty >> Diagnostic Tests >> Test R: Air Bag Tone Warning Indicator Circuit Short To Ground Or Open (DTC B1892) >> Possible Causes

Possible Causes

Air bag tone warning indicator circuit shorted to ground or open could be caused by short to ground or open in Light Blue/Black wire or damaged or inoperative GEM.

  1. Check for hard or intermittent DTC

    Ensure ignition is off. Connect scan tool to 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. Perform on-demand self-test. See ON-DEMAND SELF-TEST  under DIAGNOSTICS. If DTC B1892 was retrieved during on-demand self-test, fault is hard. Go to next step. If DTC B1892 was not retrieved, fault is intermittent. Go to step  5.
  2. Check air bag tone warning indicator circuit

    Turn ignition off. Disable air bag system. See DISABLING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Access ECS and disconnect harness connector. See ELECTRONIC CRASH SENSOR  under REMOVAL & INSTALLATION. Measure resistance between ECS connector terminals No. 13 (Light Blue/Black wire) and No. 21 (Black/Orange wire). See Figure. If resistance is more than 10 k/ohms, go to next step. If resistance is less than 10 k/ohms, repair short to ground in Light Blue/Black wire. Go to step  6.
  3. Check air bag tone warning indicator circuit for open

    Access GEM and disconnect 26-pin harness connector C240A. See GENERIC ELECTRONIC MODULE (GEM)  under REMOVAL & INSTALLATION. Measure resistance of Light Blue/Black wire between ECS connector terminal No. 13 and GEM connector C240A, terminal No. 8. See Figure & Fig 1 . If resistance is less than 100 ohms, go to next step. If resistance is more than 100 ohms, repair open in Light Blue/Black wire. Go to step  6.
  4. Check air bag tone warning indicator

    Access and disconnect 12-pin instrument cluster connector C250A. See INSTRUMENT CLUSTER  under REMOVAL & INSTALLATION. Disconnect driver-side air bag simulator. Reconnect ECS harness connector. Turn ignition to RUN position. Listen for audible warning tone. If tone was heard within one minute, go to step  6. If tone was not heard within one minute, replace ECS. Go to step  6.
  5. Check for intermittent fault

    Refer to continuous DTCs recorded in step  1. If DTC retrieved in step  1 was an intermittent fault, check for cause of intermittent short to ground or open on Light Blue/Black wire. 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 an 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 direction to appropriate test. See DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION  table. If no continuous DTCs were retrieved, reconnect air bag system. Activate air bag system. See ACTIVATING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Prove out system. Clear all DTCs. See CLEARING FAULT CODES  under DIAGNOSTICS..
    Fig 1: Identifying Generic Electronic Module (GEM) Connector
    G98C08158Courtesy of FORD MOTOR CO.