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Home >> Lincoln >> 2018 >> Navigator Select, 4WD >> Repair and Diagnosis >> Restraints >> Restraints Control Systems >> RCM Guided Routine Testing -- (4 Of 4) >> Pinpoint Tests >> Pinpoint Test UB: Second Row Left Buckle Sensor (Buckle Assembly) >> Visual Inspection and Diagnostic Pre-checks

Visual Inspection and Diagnostic Pre-checks

WARNING: Incorrect repair techniques or actions can cause an accidental SRS deployment. Never compromise or depart from these instructions. Failure to precisely follow all instructions could result in serious personal injury from an accidental deployment.
CAUTION: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to the connector.
NOTE: Most faults are due to connector and/or wiring concerns. Carry out a thorough inspection and verification before proceeding with the pinpoint test.
NOTE: Only disconnect or reconnect SRS components when instructed to do so within a pinpoint test step. Failure to follow this instruction may result in incorrect diagnosis of the SRS.
NOTE: Always make sure the correct SRS component is being installed. Parts released for other vehicles may not be compatible even if they appear physically similar. Check the part number listed in the Ford parts catalog to make sure the correct component is being installed. If an incorrect SRS component is installed, DTCs may set.
NOTE: The SRS must be fully operational and free of faults before releasing the vehicle to the customer.
Fig 1: Restraint Control Module-B (RCM-B) Connector End View (C310B)
G12765630Courtesy of FORD MOTOR CO.
Harness Side

Circuit  Pin 
  1. UB1: CHECK FOR DTC U3003:16 AND U3003:17 
    NOTE: Diagnose all network-related (lost communication) DTCs first.
    • Ignition ON, engine OFF.
    • Carry out the RCM self-test.
    • Is DTC U3003:16 or U3003:17 retrieved DTC during the self-test? 
      Yes No
      REFER to the DTC Chart. Go to  UB2.
  2. UB2: RETRIEVE RCM DTCS 
    WARNING: Before beginning any service procedure in this article, refer to Safety Warnings in General Information article. Failure to follow this instruction may result in serious personal injury.
    NOTE: Diagnose all network-related (lost communication) DTCs first.
    • Ignition ON, engine OFF.
    • Carry out the RCM self-test.
    • Is DTC B140C:11, B140C:12, B140C:13 and B140C:1D retrieved as an on-demand (not continuous) 

      DTC during the self-test? 

      Yes No
      This fault cannot be cleared until it is corrected and the DTC is no longer retrieved on-demand during self-test.
      For DTC B140C:11 or B140C:1D, Go to  UB3.
      For DTC B140C:12, Go to  UB5.
      For DTC B140C:13, Go to  UB6.
      For all others,
      No fault found.      		 This is an intermittent fault.
      Go to  UB12.
  3. UB3: CHECK THE SECOND ROW DRIVER SIDE SEATBELT SENSOR DTC FOR A FAULT STATUS CHANGE (SHORT TO GROUND OR CURRENT OUT OF RANGE INDICATED) 
    NOTE: This pinpoint test step attempts to change the fault reported by the RCM by inducing a different fault condition. If the reported fault changes, this indicates the RCM is functioning correctly and is not the source of the fault.
    • Ignition OFF.
    • Depower the SRS. REFER to the Supplemental Restraint System (SRS) Depowering in the General Procedures portion of Supplemental Restraint System article.
    • Second Row Seatbelt Buckle connector disconnected.
    • Repower the SRS. Do not prove out the SRS at this time. REFER to the Supplemental Restraint System (SRS) Repowering in the General Procedures portion of Supplemental Restraint System article.
    • Ignition ON, engine OFF.
    • Carry out the RCM self-test.
      NOTE: When viewing DTCs with the second row left seatbelt buckle switch disconnected, an open circuit fault is normally retrieved. An open circuit fault will also be retrieved for the second row right seatbelt buckle, since the second row right buckle switch circuits pass through the same connector.
    • Does the on-demand DTC change from B140C:11 or B140C:1D to B140C:13? 
      Yes No
      Go to  UB9. For DTC B140C:11, Go to  UB4.
      For DTC B140C:1D, Go to  UB10.
      For all others,
      No fault found.
  4. UB4: CHECK THE SECOND ROW LEFT SEATBELT BUCKLE SWITCH CIRCUIT FOR A SHORT TO GROUND 
    • Ignition OFF.
    • Depower the SRS. REFER to the Supplemental Restraint System (SRS) Depowering in the General Procedures portion of Supplemental Restraint System article.
    • RCM_A connector disconnected. (C310A)
    • RCM_B connector disconnected. (C310B)
    • Measure the resistance between:
      (+) Second Row Seatbelt Buckle Connector, Harness Side (-)
      2ndRW_LT_BCKL_SW_FD Ground
    • Is the resistance greater than 10, 000 ohms? 
      Yes No
      Go to  UB10. REPAIR the circuit.
  5. UB5: CHECK THE SECOND ROW LEFT SEATBELT BUCKLE SWITCH CIRCUIT FOR A SHORT TO VOLTAGE 
    • Ignition OFF.
    • Depower the SRS. REFER to the Supplemental Restraint System (SRS) Depowering in the General Procedures portion of Supplemental Restraint System article.
    • RCM_A connector disconnected. (C310A)
    • RCM_B connector disconnected. (C310B)
    • Second Row Seatbelt Buckle connector disconnected.
    • Repower the SRS. REFER to the Supplemental Restraint System (SRS) Repowering in the General Procedures portion of Supplemental Restraint System article.
    • Ignition ON, engine OFF.
    • Measure the voltage between:
      (+) Second Row Seatbelt Buckle Connector, Harness Side (-)
      2nd RW_LT_BCKL_SW_FD Ground
    • Is any voltage present? 
      Yes No
      REPAIR the circuit. Go to  UB10.
  6. UB6: CHECK THE SECOND ROW DRIVER SIDE SEATBELT SENSOR DTC FOR A FAULT STATUS CHANGE (OPEN INDICATED) 
    NOTE: This pinpoint test step attempts to change the fault reported by the RCM by inducing a different fault condition. If the reported fault changes, this indicates the RCM is functioning correctly and is not the source of the fault.
    • Ignition OFF.
      WARNING: Turn the ignition OFF and wait one minute to deplete the backup power supply. Failure to follow this instruction may result in serious personal injury or death in the event of an accidental deployment.
    • Depower the SRS. REFER to the Supplemental Restraint System (SRS) Depowering in the General Procedures portion of Supplemental Restraint System article.
    • Second Row Seatbelt Buckle connector disconnected.
    • Connect a 5 amp fused jumper wire between the following:
      Point A
      Second Row Seatbelt Buckle Connector, Harness Side      		 Point B
      Second Row Seatbelt Buckle Connector, Harness Side
      2nd RW_LT_BCKL_SW_FD SNSR_RTN
    • Repower the SRS. REFER to the Supplemental Restraint System (SRS) Repowering in the General Procedures portion of Supplemental Restraint System article.
    • Ignition ON, engine OFF.
    • Carry out the RCM self-test.
      NOTE: When viewing DTCs with the driver seatbelt buckle switch circuits shorted together, a short to ground fault is normally retrieved. An open circuit fault will also be retrieved for the second row right seatbelt buckle, since the second row right buckle switch circuits pass through the same connector.
    • Does the on-demand DTC change from B140C:13 to B140C:11? 
      Yes No
      REMOVE the fused jumper wire.
      Go to  UB9.      		 REMOVE the fused jumper wire.
      Go to  UB7.
  7. UB7: CHECK THE SECOND ROW LEFT SEATBELT BUCKLE SWITCH CIRCUIT FOR AN OPEN 
    • Ignition OFF.
    • Depower the SRS. REFER to the Supplemental Restraint System (SRS) Depowering in the General Procedures portion of Supplemental Restraint System article.
    • RCM_A connector disconnected. (C310A)
    • RCM_B connector disconnected. (C310B)
    • Measure the resistance between:
      (+) RCM_B (C310B) Connector, Harness Side (-) Second Row Seatbelt Buckle Connector, Harness Side
      2ndRW_LT_BCKL_SW_FD 2ndRW_LT_BCKL_SW_FD
    • Is the resistance less than 0.5 ohm? 
      Yes No
      Go to  UB8. REPAIR the circuit.
  8. UB8: CHECK THE SECOND ROW LEFT SEATBELT BUCKLE SWITCH GROUND CIRCUIT FOR AN OPEN 
    • Measure the resistance between:
      (+) Second Row Seatbelt Buckle Connector, Harness Side (-)
      SNSR_RTN Ground
    • Is the resistance less than 3 ohms? 
      Yes No
      Go to  UB10. REPAIR the circuit.
  9. UB9: CONFIRM THE SECOND ROW LEFT SEATBELT BUCKLE SWITCH FAULT 
    NOTE: Make sure all SRS components and the RCM electrical connectors are connected before carrying out the self-test. If not, DTCs are set.
    • Ignition OFF.
    • Depower the SRS. REFER to the Supplemental Restraint System (SRS) Depowering in the General Procedures portion of Supplemental Restraint System article.
    • Prior to reconnecting any previously disconnected SRS component:
      • inspect connector(s) (including any inline connectors) for pushed-out, loose or spread terminals and loose or frayed wire connections at terminals.
      • inspect wire harness for any damaged, pinched, cut or pierced wires.
      • inspect the RCM electrical Connector Position Assurance (CPA) lever/locks for correct operation.
      • repair any concerns found. Refer to OEM GROUND DISTRIBUTION article, for schematic and connector information.
    • Second Row Seatbelt Buckle connector connected. (if previously disconnected).
    • Repower the SRS. REFER to the Supplemental Restraint System (SRS) Repowering in the General Procedures portion of Supplemental Restraint System article.
    • Ignition ON, engine OFF.
    • Carry out the RCM self-test.
    • Is the original DTC retrieved on-demand during self-test? 
      Yes No
      INSTALL a new rear seatbelt buckle assembly (includes second row left inflatable seatbelt buckle).
      REFER to the appropriate Removal and Installation procedure in Seatbelt Systems article      		 In the process of diagnosing the fault, the fault condition has become intermittent. Do not install any new SRS components at this time.
      Install SRS components only when directed to do so in the pinpoint test.
      Go to  UB12.
  10. UB10: CONFIRM THE RCM FAULT 
    NOTE: Make sure all SRS components and the RCM electrical connectors are connected before carrying out the self-test. If not, DTCs are set.
    • Ignition OFF.
    • Depower the SRS. REFER to the Supplemental Restraint System (SRS) Depowering in the General Procedures portion of Supplemental Restraint System article.
    • Prior to reconnecting any previously disconnected SRS component:
      • inspect connector(s) (including any inline connectors) for pushed-out, loose or spread terminals and loose or frayed wire connections at terminals.
      • inspect wire harness for any damaged, pinched, cut or pierced wires.
      • inspect the RCM Connector Position Assurance (CPA) lever/locks for correct operation.
      • repair any concerns found. Refer to OEM GROUND DISTRIBUTION article, for schematic and connector information.
    • RCM_A connector connected. (C310A) (if previously disconnected).
    • RCM_B connector connected. (C310B) (if previously disconnected).
    • Second Row Seatbelt Buckle connector connected.
    • Repower the SRS. REFER to the Supplemental Restraint System (SRS) Repowering in the General Procedures portion of Supplemental Restraint System article.
    • Ignition ON, engine OFF.
    • Carry out the RCM self-test.
    • Is the original DTC retrieved on-demand during self-test? 
      Yes No
      Go to  UB11. In the process of diagnosing the fault, the fault condition has become intermittent. Do not install any new SRS components at this time.
      Install SRS components only when directed to do so in the pinpoint test.
      Go to  UB12.
  11. UB11: CONFIRM THE REPAIR 
    • Ignition OFF.
    • CHECK OASIS for any applicable TSBs.
      • If a TSB exists for this concern, DISCONTINUE this test and FOLLOW TSB instructions.
      • If no TSBs address this concern, INSTALL a new RCM. Refer to the appropriate Removal and Installation procedure in Supplemental Restraint System article.

    INSTALL a new RCM.

    Reconnect all previously disconnected SRS components and repower the SRS. REFER to the Supplemental Restraint System (SRS) Repowering in the General Procedures portion of Supplemental Restraint System article.

    Carry out the OCSM and RCM self-test and record DTCs if present. Do not clear any DTCs until all DTCs have been resolved. DIAGNOSE and REPAIR the RCM and/or OCSM DTCs.

    Carry out the OCSM and RCM self-test and record DTCs if present. Do not clear any DTCs until all DTCs have been resolved.

    If any SRS DTCs are retrieved, DO NOT clear any DTCs until all DTCs have been resolved. DIAGNOSE and REPAIR the RCM and/or OCSM DTCs.

    If no DTCs are retrieved on-demand, the repair is complete. RETURN the vehicle to the customer.

  12. UB12: CHECK FOR AN INTERMITTENT FAULT 
    • Ignition OFF.
    • Depower the SRS. REFER to the Supplemental Restraint System (SRS) Depowering in the General Procedures portion of Supplemental Restraint System article.
    • Second Row Seatbelt Buckle connector disconnected.
    • Inspect:
      • connector(s) (including any inline connectors) for corrosion, loose or spread terminals and loose or frayed wire connections at terminals.
      • wire harness for any damage, pinched, cut or pierced wires.
      • the RCM Connector Position Assurance (CPA) lever/locks for correct operation.
      • repair any concerns found. Refer to OEM GROUND DISTRIBUTION article, for schematic and connector information.
    • Connect all previously disconnected component(s)/connector(s).
    • Repower the SRS. REFER to the Supplemental Restraint System (SRS) Repowering in the General Procedures portion of Supplemental Restraint System article.
    • Ignition ON, engine OFF.
    • Carry out the RCM self-test.
    • Is DTC B140C:11, B140C:12, B140C:13 and B140C:1D retrieved on-demand during self-test? 
      Yes No
      This fault cannot be cleared until it is corrected and the DTC is no longer retrieved on-demand during self-test.
      For DTC B140C:11 or B140C:1D, Go to  UB3.
      For DTC B140C:12, Go to  UB5.
      For DTC B140C:13, Go to  UB6.
      For all others,
      No fault found.      		 The fault is not present and cannot be recreated at this time. Do not install any new SRS components at this time. Install SRS components only when directed to do so in the pinpoint test.
  13. UB13: CHECK FOR ADDITIONAL SRS DIAGNOSTIC TROUBLE CODES (DTCS) 
    WARNING: Turn the ignition OFF and wait one minute to deplete the backup power supply. Failure to follow this instruction may result in serious personal injury or death in the event of an accidental deployment.
    • Ignition OFF.
    • Reconnect all SRS components (if previously disconnected).
    • If previously directed to depower the SRS, repower the SRS. Do not prove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Repowering in Supplemental Restraint System article.
    • Ignition ON, engine OFF.
    • Clear the RCM DTCs.
    • Ignition OFF.
    • Ignition ON, engine OFF.
    • Wait 10 seconds.
    • Carry out the RCM self-test.
    • If equipped with an OCSM, carry out the OCSM self-test.
    • Carry out the OCS self-test.
    • If equipped with an BECMB, carry out the BECMB self-test.
    • Carry out the BECMB self-test.
    • Are any RCM, OCSM and/or BECMB DTCs retrieved on-demand during self-test? 
      Yes No
      Do not clear any DTCs until all DTCs have been resolved. REFER to the RCM - RESTRAINT CONTROL MODULE , OCS - OCCUPANT CLASSIFICATION SYSTEM or BECMB - EXTENDED POWER MODULE DTC Chart. The repair is complete. RETURN the vehicle to the customer.
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