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Home >> Ford >> 2000 >> Taurus LX, 3.0 2, AX4N >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Supplemental Inflatable Restraint System >> Diagnostic Tests >> Test A: Air Bag Warning Light On Continuously-RCM Disconnected, Inoperative Or Lost/Low Ignition Feed >> Possible Causes

Possible Causes

An AIR BAG warning light that is continuously illuminated may be caused by ignition circuit damage, disconnected Restraints Control Module (RCM) module, loss of RCM ground circuit, damaged battery or ignition circuit, inoperative RCM or damaged scan tool.

  1. Check for hard or intermittent self-test DTC

    Ensure ignition is off. Connect scan tool to DLC. See USING SCAN TOOL  . Turn ignition switch to RUN position. Retrieve and record any continuous DTCs. See RETRIEVING FAULT CODES  under DIAGNOSTICS. Clear continuous DTCs. See CLEARING FAULT CODES  under DIAGNOSTICS. Perform on-demand self-test. See ON-DEMAND SELF-TEST  under DIAGNOSTICS. If continuous DTCs were retrieved, go to step  3 . If on-demand DTCs were retrieved, go to diagnostic trouble code identification table for direction to appropriate test. See DIAGNOSTIC TROUBLE CODE IDENTIFICATION  table. If no DTCs were retrieved, go to next step.
  2. Check RCM connection

    Turn ignition off. Access Restraints Control Module (RCM). See RESTRAINTS CONTROL MODULE  under REMOVAL & INSTALLATION. Ensure both RCM connectors are fully connected to RCM and Red locking tabs are engaged. If RCM connectors are connected correctly, go to next step. If RCM connectors are not connected correctly or locking tabs are not engaged, connect and engage as necessary, then go to step  7 .
  3. Check RCM connector

    Turn ignition off. Access Restraints Control Module (RCM) and disconnect connectors. See RESTRAINTS CONTROL MODULE  under REMOVAL & INSTALLATION. Inspect RCM, component side of RCM connectors for worn or damaged camming beam and/or any foreign material. See Fig 1 . Inspect RCM connectors for worn, damaged or dislodged shorting bars. If camming beams and shorting bars are okay, go to next step. If camming beams and shorting bars are defective, repair or replace as necessary and go to step  7 .
  4. Check RCM ignition circuit for open

    Disable air bag system. See DISABLING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Turn ignition switch to RUN position. Measure voltage between sheet metal ground near RCM and RCM harness connector C310A, terminal No. 1 (White/Yellow wire). See Fig 2 . If voltage is 8-18 volts, go to next step. If voltage is not 8-18 volts, repair open in White/Orange wire, then go to step  7 .
  5. Check ground circuit for open

    Turn ignition off. Measure resistance between sheet metal ground near RCM and RCM harness connector C310A, terminal No. 10 (Black/Orange wire). If resistance is less than 10 ohms, go to next step. If resistance is more then 10 ohms, repair open in Black/Orange wire and go to step  7 .
  6. Check for short to ground

    Access and disconnect instrument cluster connector. Reconnect RCM harness connector C310A. Measure resistance between ground and instrument cluster harness connector C220B, terminal No. 11 (Black/Yellow wire). If resistance is less than 10 k/ohms, repair short to ground in Black/Yellow wire and go to next step. See WIRING DIAGRAMS  . If resistance is more than 10 k/ohms, install NEW RCM. 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. See DIAGNOSTIC TROUBLE CODE IDENTIFICATION  table. If no DTCs were retrieved, reconnect and 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 Camming Beam & Shorting Bars
    G99B00829Courtesy of FORD MOTOR CO.
    Fig 2: Identifying Restraints Control Module (RCM) Harness Connectors
    G99A21733Courtesy of FORD MOTOR CO.