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Home >> Ford >> 2000 >> Contour SE, 2.0 3, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 268 (Supplemental Restraint System - Air Bag Restraint Systems) >> Diagnostic Tests >> Test D: Air Bag Tone Warning Indicator Circuit Short To Battery (DTC B1891) >> Possible Causes

Possible Causes

WARNING: This page is about a different car, the 2004 Mercury Mountaineer and 2004 Ford Explorer. 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.

  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 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 .

  2. 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 (Dark Blue wire, circuit No. 1390). 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 Dark Blue 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 Dark Blue wire. DTC B1891 should not be retrieved.

  3. 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 .

  4. 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 Light Blue/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.

  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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