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Home >> Ford >> 2000 >> Contour SE, 2.5 L, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 105 (Supplemental Inflatable Restraint System) >> Diagnostic Tests >> Test L: Passenger Air Bag Deactivation (Pad) Switch Fault (DTC B1871) >> Possible Causes

Possible Causes

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

An invalid PAD switch resistance could be caused by damaged or inoperative PAD switch, damaged or inoperative RCM, a short to battery, short to ground or open in White/Light Blue wire (circuit No. 1112).

  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 B1871 was retrieved during on-demand self-test, fault is hard. Go to next step. If DTC B1871 was not retrieved, fault is intermittent. Go to step  6 .

  2. Check PAD switch on position

    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. Turn PAD switch to ON position. Measure resistance between RCM connector terminals No. 8 (White/Light Blue wire) and No. 21 (Black/Orange wire, circuit No. 649). See Figure . If resistance is 900-1100 ohms, go to next step. If resistance is not 900-1100 ohms, go to step  4 .

  3. Check PAD switch OFF position

    Turn PAD switch to OFF position. Measure resistance between RCM connector terminals No. 8 (White/Light Blue wire) and No. 21 (Black/Orange wire). If resistance is 400-600 ohms, replace RCM. Go to step  7 . If resistance is not 400-600 ohms, go to next step.

  4. Check circuit for short to battery

    Turn ignition switch to RUN position. Measure voltage between ground and RCM connector terminal No. 8 (White/Light Blue wire). If voltage is more than 0.2 volt, repair short to battery in White/Light Blue wire. See WIRING DIAGRAMS  . Go to step  7 . If voltage is less than 0.2 volt, go to next step.

  5. Check circuit for open

    Turn ignition switch to OFF position. Access PAD switch and disconnect connector. See PASSENGER-SIDE AIR BAG DEACTIVATE (PAD) SWITCH  under REMOVAL & INSTALLATION. Measure resistance in White/Light Blue wire between RCM connector terminal No. 8 and PAD switch harness connector. If resistance is less than 10 ohms, replace PAD switch. Go to step  7 . If resistance is more than 10 ohms, repair open in White/Light Blue wire. Go to step  7 .

  6. 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 faults in White/Light Blue wire (circuit No. 1112). 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.

  7. 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. Perform system operation check. See SYSTEM OPERATION CHECK  . Clear all DTCs. See CLEARING FAULT CODES  under DIAGNOSTICS.
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