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Home >> Ford >> 2002 >> Taurus SES, 3.0 S >> Repair and Diagnosis >> External Pages >> Different car >> Section 219 (Supplemental Inflatable Restraint System) >> Diagnostic Tests >> Test T: Seat Track Position Sensor Circuit Fault (DTC C1981) >> Possible Causes

Possible Causes

WARNING: This page is about a different car, the 2003 Mercury Sable and 2003 Ford Taurus. However, it is still accessible from the selected car via links, so may be relevant.

A seat track position sensor short to battery circuit fault could be caused by damaged wiring, terminals or connectors 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 RUN 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 C1981 was retrieved during on-demand self-test, fault is hard. Go to next step. If DTC C1981 was not retrieved, fault is intermittent. Go to step  12 .

  2. Check circuits for open between RCM & left front seat

    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 C310B. See RESTRAINTS CONTROL MODULE (RCM)  under REMOVAL & INSTALLATION. Disconnect air bag simulator from left front under-seat harness connector. Measure resistance between harness side of RCM connector C310B, terminal No. 23 and harness side left front under-seat connector C313F, terminal No. 7 (Light Green wire, circuit No. 1520). See Figure & Figure . If resistance is less than 0.5 ohm, go to next step. If resistance is more than 0.5 ohm, repair open in Light Green wire. See WIRING DIAGRAMS  .

  3. Check circuits for open between RCM & left front seat

    Measure resistance between harness side of RCM connector C310B, terminal No. 24 and harness side left front under-seat connector C313F, terminal No. 2 (Light Green/Orange wire, circuit No. 1558). If resistance is less than 0.5 ohm, go to next step. If resistance is more than 0.5 ohm, repair open in Light Green wire.

  4. Check circuit for short to voltage between RCM & left front seat

    Turn ignition switch to RUN position. Measure voltage between ground and harness side of RCM connector, terminal No. 23 (Light Green wire, circuit No. 1520). If voltage is less than 0.2 volt, go to next step. If voltage is more than 0.2 volt, repair short to battery in Light Green wire. Go to step  13 .

  5. Check circuits for short to battery between left front seat & ground

    Measure voltage between ground and harness side of RCM connector, terminal No. 24 (Light Green/Orange wire, circuit No. 1558). If voltage is less than 0.2 volt, go to next step. If voltage is more than 0.2 volt, repair short to battery in Light Green/Orange wire. Go to step  13 .

  6. Check circuit for open between left front seat & seat track position sensor

    Turn ignition switch to OFF position. Access and disconnect seat track position sensor connector. See SEAT TRACK POSITION SENSOR  under REMOVAL & INSTALLATION. Measure resistance in Light Green wire between harness side of left front under-seat connector C313M, terminal No. 7 and harness side seat track position sensor connector. See Figure . If resistance is less than 0.5 ohm, go to next step. If resistance is more than 0.5 ohm, replace left front in-seat harness. Go to step  13 .

  7. Check circuit for open between left front seat & seat track position sensor

    Measure resistance in Light Green/Orange wire between harness side of left front under-seat connector C313M, terminal No. 2 and harness side seat track position sensor connector. If resistance is less than 0.5 ohm, go to next step. If resistance is more than 0.5 ohm, replace left front in-seat harness. Go to step  13 .

  8. Check circuit for short to voltage between left front seat & seat track position sensor

    Measure resistance between harness side of left front in-seat connector C313M, terminal No. 7 (Light Green wire) and all other terminals in connector. If resistance is more than one megohm in all terminals, go to next step. If resistance is less than one megohm at any terminal, replace left front in-seat harness. Go to step  13 .

  9. Check circuit for short to voltage between left front seat & seat track position sensor

    Measure resistance between harness side of left front in-seat connector C313M, terminal No. 2 (Light Green/Orange wire) and all other terminals in connector. If resistance is more than one megohm in all terminals, go to next step. If resistance is less than one megohm at any terminal, replace left front in-seat harness. Go to step  13 .

  10. Check seat track position sensor

    Install a known-good seat track position sensor. Disconnect air bag simulators from right front under-seat harness connector. Disconnect right and left seat belt pretensioner harness connectors at pretensioners. Install front seat(s). DO NOT activate air bag system at this time. Install Air Bag Simulators (418-F395/014-R1079) on harness side of right and left seat belt pretensioners harness connectors. Reconnect right and left front under-seat harness connectors. Reconnect RCM harness connector C310B. Perform on-demand-self-test. If DTC C1981 was retrieved during on-demand self-test, go to next step. If DTC C1981 was not retrieved, fault is corrected. Go to step  13 .
    NOTE: Ensure all air bag system simulators, sensor electrical connectors and RCM electrical connectors are connected prior to carrying out on-demand self-test or erroneous faults may be set.

  11. Confirm RCM fault

    Turn ignition switch to OFF position. Reinstall original seat track position sensor. Perform on-demand-self-test. If DTC C1981 was retrieved during on-demand self-test, replace RCM. Go to step  13 . If DTC C1981 was not retrieved during on-demand self-test, fault is corrected. Go to step  13 .

  12. Check for intermittent DTC

    Disable air bag system. See DISABLING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Perform on-demand self-test. If DTC C1981 was retrieved during on-demand self-test, go to step  2 . If DTC C1981 was not retrieved during on-demand self-test, check for cause of intermittent fault. Attempt to recreate fault by flexing wire harness and cycling ignition switch frequently. Repair any intermittent problems found. Go to next step.

  13. 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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