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Home >> Ford >> 2000 >> Contour SE, 2.0 3, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 109 (Supplemental Inflatable Restraint System) >> Diagnostic Tests >> Test Ag: Air Bag Warning Light Short To Battery (DTC B1870) >> Possible Causes

Possible Causes

WARNING: This page is about a different car, the 2002 Ford Escape. 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 Black/Yellow wire (circuit No. 608), instrument cluster malfunction 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 B1870 was retrieved during on-demand self-test, fault is hard. Go to next step. If DTC B1870 was not retrieved, fault is intermittent. Go to step  4 .

  2. Check AIR BAG warning light circuit

    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 C2041A. See RESTRAINTS CONTROL MODULE (RCM)  under REMOVAL & INSTALLATION. Turn ignition switch to RUN position. If AIR BAG warning light illuminates, go to next step. If AIR BAG warning light does not illuminate, check AIR BAG warning light bulb. If bulb is okay, repair Black/Yellow wire. See WIRING DIAGRAMS  . Go to step  5 .

  3. Check AIR BAG warning light circuit for short to battery

    Turn ignition switch to OFF position. Access and disconnect instrument cluster harness connector C220B. See INSTRUMENT CLUSTER  under REMOVAL & INSTALLATION. Access RCM and disconnect harness connector C2041A. Turn ignition switch to RUN position. Measure voltage between ground and harness side of RCM connector C2041A, terminal No. 20 (Black/Yellow wire, circuit No. 608). If voltage is more than 0.2 volt, repair short to battery in Black/Yellow wire. Go to step  5 . If voltage is less than 0.2 volt, repair instrument cluster as necessary. 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 battery in Black/Yellow 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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