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Home >> Ford >> 2000 >> Contour SE, 2.5 L, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 110 (Air Bag Restraint Systems) >> Diagnostic Tests >> Test Ac: Air Bag Tone Warning Indicator Circuit Short To Battery Or Ignition (B1891) >> Possible Causes

Possible Causes

WARNING: This page is about a different car, the 2002 Lincoln Navigator and 2002 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.

Air bag tone warning indicator circuit shorted to battery or ignition voltage could be caused by short to battery or ignition voltage in Light Blue/Black wire, damaged or inoperative GEM or RCM internal fault.

  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. 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

    Turn ignition switch to OFF position. Disable air bag system. See DISABLING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Leave negative battery cable disconnected. Access RCM and disconnect harness connector C2005. See RESTRAINTS CONTROL MODULE (RCM)  under REMOVAL & INSTALLATION. Access GEM and disconnect 26-pin harness connector. See GENERIC ELECTRONIC MODULE (GEM)  under REMOVAL & INSTALLATION. Turn ignition switch to RUN position. Measure resistance between harness side of RCM connector C2005, terminals No. 26 (Light Blue/Black wire) and No. 2 (Violet/Orange wire, circuit No. 298). See Figure . If resistance is less than 10 k/ohms, repair short to battery in Light Blue/Black wire. See WIRING DIAGRAMS  . Go to step  5 . If resistance is more than 10 k/ohms, go to next step.

  3. Check air bag tone warning indicator

    Turn ignition switch to OFF position. Reconnect negative battery cable. Reconnect GEM connector. Turn ignition switch to RUN position. Connect fused jumper wire between ground and RCM connector C2005, terminal No. 26 (Light Blue/Black wire). Listen for audible warning tone. If warning tone was heard, replace RCM. Go to step  5 . If warning tone was not heard, replace GEM. Go to step  5 .

  4. 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 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. If DTC retrieved in step  1 was not an intermittent fault, 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. DO NOT clear any DTCs until all DTCs have been resolved. 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. Clear all DTCs. See CLEARING FAULT CODES  under DIAGNOSTICS.
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