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Home >> Ford >> 2003 >> Excursion 5.4 L, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 211 (Supplemental Inflatable Restraint System) >> Diagnostic Tests >> Test I: Occupant Classification Sensor (OCS) Failure (DTC B2290) >> Possible Causes
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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.

OCS circuit fault could be caused by damaged wiring, terminals or connectors, faulty OCS system 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. Retrieve, flag and record any continuous Diagnostic Trouble Codes (DTCs). See RETRIEVING FAULT CODES  under DIAGNOSTICS. Flag DTC B2290. See BIT-MAPPED DIAGNOSTIC TROUBLE CODES  under DIAGNOSTICS. Retrieve and record any flagged DTCs. Perform on-demand self-test. See ON-DEMAND SELF-TEST  under DIAGNOSTICS. Retrieve and record any flagged DTCs. If flagged fault "?" was retrieved during on-demand self-test, multiple faults exist and all steps of diagnostic procedure must be performed. On models equipped with original part OCS, if DTC B2290 was retrieved during on-demand self-test, fault is hard.
    • For communication (OCSCOM) fault, go to next step.
    • For OCS mounting (MOUNT) fault, go to step  19 .
    • For internal (MODL FT) fault, replace OCS system. See OCCUPANT CLASSIFICATION SENSOR (OCS)  under REMOVAL & INSTALLATION. Go to step  21 .
    • For calibration (CAL FT) fault, replace OCS system. Go to step  21 .
    • For OCS pressure sensor (SENF) fault, go to step  11 .
    • If DTC B2290 was not retrieved during on-demand self-test, fault is intermittent. Go to step  20 .

      On models equipped with service part OCS, if DTC B2290 was retrieved during on-demand self-test, fault is hard.

    • For communication (OCSCOM) fault, go to next step.
    • For internal (MODL FT) fault, replace OCS system. See OCCUPANT CLASSIFICATION SENSOR (OCS)  under REMOVAL & INSTALLATION. Go to step  21 .
    • For calibration (CAL FT) fault, replace OCS system. Go to step  21 .
    • For OCS pressure sensor (SENF) fault, replace OCS system. Go to step  21 .
    • If DTC B2290 was not retrieved during on-demand self-test, fault is intermittent. Go to step  20 .

  2. Check seat wiring & connectors

    Turn ignition switch to OFF position. Disable air bag system. See DISABLING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Visually inspect all OCS system and seat wiring harnesses and connectors, including RCM harness connector C310B terminals No. 33 and 34. See WIRING DIAGRAMS  . See Figure . If wiring harnesses and connectors are okay, go to next step. If wiring harnesses and connectors are damaged, repair as necessary. Go to step  21 .

  3. Check ignition circuit for open

    Access and disconnect OCS connector C3043 from OCS Electronic Control Unit (ECU). See OCCUPANT CLASSIFICATION SENSOR (OCS)  under REMOVAL & INSTALLATION. Turn ignition switch to ON position. Measure voltage between ground and harness side of OCS connector C3043, terminal "G" (Red/White wire, circuit No. 937). See Fig 1 . If voltage is more than 10 volts, go to next step. If voltage is less than 10 volts, repair open in Red/White wire. Go to step  21 . See WIRING DIAGRAMS  .

  4. Check ground circuit for open

    Turn ignition switch to OFF position. Measure resistance between ground and OCS connector C3043, terminal "D" (Black/Light Blue wire, circuit No. 1203). If resistance is less than 5 ohms, go to next step. If resistance is more than 5 ohms, repair open in Black/Light Blue wire. Go to step  21 .

  5. Check for short to battery between OCS electronic control unit & RCM

    Access and disconnect RCM connectors C310A and C310B. See RESTRAINTS CONTROL MODULE (RCM)  under REMOVAL & INSTALLATION. Turn ignition switch to ON position. Measure voltage between ground and harness side of OCS connector C3043, terminal "E" (Brown/White wire, circuit No. 1918). Measure voltage between ground and harness side of OCS connector C3043, terminal "F" (Pink/Orange wire, circuit No. 1919). If voltage is less than 0.2 volt in both circuits, go to next step. If voltage is more than 0.2 volt in either circuit, repair short to battery in appropriate wire. Go to step  21 .

  6. Check for short to ground between OCS electronic control unit & RCM

    Turn ignition switch to OFF position. Measure resistance between ground and harness side of OCS connector C3043, terminal "E" (Brown/White wire). Measure resistance between ground and harness side of OCS connector C3043, terminal "F" (Pink/Orange wire). If resistance is more than 10 k/ohms in both circuits, go to next step. If resistance is less than 10 k/ohms in either circuit, repair short to ground in appropriate wire. Go to step  21 .

  7. Check circuit for open between OCS electronic control unit & RCM

    Measure resistance between harness side of RCM connector C310B, terminal No. 34 and harness side of OCS connector C3043, terminal No. "E" (Brown/White wire). 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 Brown/White wire. Go to step  21 .

  8. Check circuit for open between OCS electronic control unit & RCM

    Measure resistance between harness side of RCM connector C310B, terminal No. 33 and harness side of OCS connector C3043, terminal "F" (Pink/Orange wire). If resistance is less than 0.5 ohm, go to next step. If resistance is more than 0.5 ohm, repair open in Pink/Orange wire. Go to step  21 .

  9. Check circuit for short between OCS electronic control unit & RCM

    Measure resistance between harness side of OCS connector C3043, terminals "E" (Brown/White wire) and "F" (Pink/Orange wire). If resistance is more than 10 k/ohms, go to next step. If resistance is less than 10 k/ohms, repair short between Brown/White and Pink/Orange wires. Go to step  21 .
    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.

  10. Check RCM

    Install known good RCM. Reconnect both RCM connectors. Turn ignition switch to ON position. Reconnect OCS harness connector C3043. Perform on-demand self-test. Flag DTC B2290. Retrieve and record any flagged faults. If DTC B2290 was retrieved during on-demand self-test, replace OCS system. Go to step  21 . If DTC B2290 was not retrieved during on-demand self-test, fault is corrected. Go to step  21 .

  11. Check seat wiring & connectors

    Disable air bag system. See DISABLING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Visually inspect all OCS system and seat wiring harnesses and connectors. If wiring harnesses and connectors are okay, go to next step. If wiring harnesses and connectors are damaged, repair as necessary. Go to step  21 .

  12. Check circuits for short to battery

    Access and disconnect both RCM connectors. See RESTRAINTS CONTROL MODULE (RCM)  under REMOVAL & INSTALLATION. Access and disconnect OCS connector C3042 from OCS pressure sensor. See OCCUPANT CLASSIFICATION SENSOR (OCS)  under REMOVAL & INSTALLATION. Access and disconnect OCS connector C3043 from OCS Electronic Control Unit (ECU). See OCCUPANT CLASSIFICATION SENSOR (OCS)  under REMOVAL & INSTALLATION. Turn ignition switch to ON position. Measure voltage between ground and harness side of OCS pressure sensor connector C3042, terminals "C" (Red/White wire, circuit No. 1568), "B" (Tan/Black wire, circuit No. 1570) and "A" (Gray/Dark Blue wire, circuit No. 1569). See Fig 2 . If voltage is more than 0.2 volt in any circuit, repair short to battery in appropriate wire. Go to step  21 . If voltage is less than 0.2 volt in all circuits, go to next step.

  13. Check circuits for short to ground

    Turn ignition switch to OFF position. Measure resistance between ground and harness side of OCS pressure sensor connector C3042, terminals "C" (Red/White wire), "B" (Tan/Black wire) and "A" (Gray/Dark Blue wire). If resistance is more than 10 k/ohms in all circuits, go to next step. If resistance is less than 10 k/ohms in any circuit, repair short to ground in appropriate circuit. Go to step  21 .

  14. Check circuit for open between OCS pressure sensor & OCS electronic control unit

    Measure resistance between harness side of OCS ECU connector C3043, terminal "J" and harness side of OCS pressure sensor connector C3042, terminal "C" (Red/White wire). See Fig 1 & Fig 2 . If resistance is less than 0.5 ohm, go to next step. If resistance is more than 0.5 ohm, repair open in Red/White wire. Go to step  21 .

  15. Check circuit for open between OCS pressure sensor & OCS electronic control unit

    Measure resistance between harness side of OCS ECU connector C3043, terminal "H" and harness side of OCS pressure sensor connector C3042, terminal "A" (Gray/Dark Blue wire). If resistance is less than 0.5 ohm, go to next step. If resistance is more than 0.5 ohm, repair open in Gray/Dark Blue wire. Go to step  21 .

  16. Check circuit for open between OCS pressure sensor & OCS electronic control unit

    Measure resistance between harness side of OCS ECU connector C3043, terminal "K" and harness side of OCS pressure sensor connector C3042, terminal "B" (Tan/Black wire). 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  21 .

  17. Check circuits for short

    Measure resistance between harness side of OCS pressure sensor connector C3042, terminal "C" (Red/White wire) and "B" (Tan/Black wire). Measure resistance between harness side of OCS pressure sensor connector C3042, terminal "C" (Red/White wire) and "A" (Gray/Light Blue wire). Measure resistance between harness side of OCS pressure sensor connector C3042, terminal "B" (Tan/Black wire) and "A" (Gray/Light Blue wire). If resistance is more than 10 k/ohms between all circuits, go to next step. If resistance is less 10 k/ohms between any circuit, repair short between appropriate wires. Go to step  21 .
    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.

  18. Check OCS

    Install NEW OCS system service kit. Reconnect RCM connectors. Zero OCS. See ZERO OCCUPANT CLASSIFICATION SENSOR (OCS)  under DIAGNOSTICS. Turn ignition switch to ON position. Perform on-demand self-test. Flag DTC B2290. Retrieve and record any flagged faults. If flagged fault "?" was retrieved during on-demand self-test, multiple faults exist and all steps of diagnostic procedure must be performed. If DTC B2290 was retrieved during on-demand self-test, replace RCM. Go to step  21 . If DTC B2290 was retrieved during on-demand self-test, fault is corrected. Go to step  21 .

  19. Check for OCS mounting fault

    Turn ignition switch to OFF position. Disable air bag system. See DISABLING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Inspect OCS Electronic Control Unit (ECU) for correct mounting location and direction. Ensure the OCS ECU fasteners are tight and no damage exists to OCS ECU and seat cushion pan. If OCS ECU is properly mounted and no damage is noted, replace OCS system. Go to step  21 . If OCS ECU is not properly mounted or damage is noted, repair or replace components as necessary. Go to step  21 .

  20. Check for intermittent fault

    Turn ignition switch to OFF position. Disable air bag system. See DISABLING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Turn ignition switch to ON position. Perform on-demand self-test. If flagged fault "?" was retrieved during on-demand self-test in step  1 , multiple faults exist and all steps of diagnostic procedure must be performed. On models equipped with original part OCS, if DTC B2290 was retrieved during on-demand self-test, fault is hard.
    • For communication (OCSCOM) fault, go to step  2 .
    • For OCS mounting (MOUNT) fault, go to step  19 .
    • For internal (MODL FT) fault, replace OCS system. See OCCUPANT CLASSIFICATION SENSOR (OCS)  under REMOVAL & INSTALLATION. Go to step  21 .
    • For calibration (CAL FT) fault, replace OCS system. Go to step  21 .
    • For OCS pressure sensor (SENF) fault, go to step  11 .

      On models equipped with service part OCS, if DTC B2290 was retrieved during on-demand self-test, fault is hard.

    • For communication (OCSCOM) fault, go to step  2 .
    • For internal (MODL FT) fault, replace OCS system. See OCCUPANT CLASSIFICATION SENSOR (OCS)  under REMOVAL & INSTALLATION. Go to step  21 .
    • For calibration (CAL FT) fault, replace OCS system. Go to step  21 .
    • For OCS pressure sensor (SENF) fault, go to step  11 .

    If DTC B2290 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. Activate other systems in same wire harness. Repair any intermittent problems found. Go to next step.

  21. 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 Occupant Classification Sensor (OCS) Module Connector C3043
G99F27412Courtesy of FORD MOTOR CO.
Fig 2: Identifying Occupant Classification Sensor (OCS) Pressure Sensor Connector C3042 Terminals
G99E27478Courtesy of FORD MOTOR CO.
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