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Home >> Ford >> 2000 >> Contour SE, 2.5 L, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 272 (Supplemental Inflatable Restraint System) >> Diagnostic Tests >> Test Y: Seat Track Position Sensor Open (DTC C1946) >> Possible Causes

Possible Causes

WARNING: This page is about a different car, the 2004 Mercury Monterey and 2004 Ford Freestar. However, it is still accessible from the selected car via links, so may be relevant.

A seat track position sensor open circuit fault could be caused by damaged wiring, terminals or connectors, faulty seat track position sensor 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 ON 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 C1946 was retrieved during on-demand self-test, fault is hard. Go to next step. If DTC C1946 was not retrieved, fault is intermittent. Go to step  8 .

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

    Turn ignition switch to OFF position. Disable air bag system. See DISABLING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. On models equipped with side air bag modules, ensure left front seat is removed from vehicle. On all models, access RCM and disconnect connector C310B. See RESTRAINTS CONTROL MODULE (RCM)  under REMOVAL & INSTALLATION. Disconnect left front seat connector C312. Measure resistance between harness side RCM connector C310B, terminal No. 23 and harness side of left front seat connector C312, terminal No. 2 (Light Green wire, circuit No. 1520). See Figure & Fig 1 . 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  . Go to step  9 .

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

    Measure resistance between harness side of RCM connector C310B, terminal No. 24 and harness side of left front seat connector C312, terminal No. 3 (Tan/Black 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 Tan/Black wire. Go to step  9 .

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

    Disconnect seat track position sensor connector. Measure resistance in Light Green wire between sensor side of left front seat connector C312, terminal No. 2 and harness side of 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, repair open in Light Green wire. Go to step  9 .

  5. Check circuit for open between left front seat & RCM

    Measure resistance in Tan/Black wire between sensor side of left front seat connector C312, terminal No. 1 and harness side of seat track position sensor connector. See Fig 1 . If resistance is less than 0.5 ohm, go to next step. If resistance is more than 0.5 ohm, repair open in Tan/Black wire. Go to step  9 .

  6. Check seat track position sensor

    Reconnect RCM connector C310B. Install known-good seat track position sensor. See SEAT TRACK POSITION SENSOR  under REMOVAL & INSTALLATION. On models equipped with side air bag modules, position left front seat in vehicle. On all models, reconnect seat harness connector C312. Turn ignition switch to ON position. Perform on-demand self-test. If DTC C1946 was retrieved during on-demand self-test, go to next step. If DTC C1946 was not retrieved, attempt to recreate fault by flexing wire harness and cycling ignition switch frequently. Activate other systems in same wire harness. Repair any intermittent problems found. Go to step  9 .
    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.

  7. Confirm RCM Fault

    Turn ignition switch to OFF position. Reinstall original seat track position sensor. Turn ignition switch to ON position. Perform on-demand self-test. If DTC C1946 was retrieved during on-demand self-test, replace RCM. Go to step  9 . If DTC C1946 was not retrieved during on-demand self-test, attempt to recreate fault by flexing wire harness and cycling ignition switch frequently. Activate other systems in same wire harness. Repair any intermittent problems found. Go to step  9 .

  8. Check for intermittent fault

    Turn ignition switch to OFF position. Disable air bag system. See DISABLING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Perform on-demand self-test. If DTC C1946 was retrieved during on-demand self-test, go to step  2 . If DTC C1946 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.

  9. 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.
Fig 1: Identifying Left Front Seat Harness Connector C312 Terminals
G99I29569Courtesy of FORD MOTOR CO.
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