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Home >> Audi >> 2016 >> S5 Prestige, 2D Convertible >> Repair and Diagnosis >> External Pages >> Different car >> Section 1148 (RCM Guided Routine Testing -- (2 Of 4)) >> Pinpoint Tests >> Pinpoint Test AX: Passenger Seatbelt Tension Sensor (Passenger Seatbelt Buckle) >> Visual Inspection and Diagnostic Pre-checks

Visual Inspection and Diagnostic Pre-checks

WARNING: This page is about a different car, the 2018 Lincoln Navigator. However, it is still accessible from the selected car via links, so may be relevant.
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.
NOTE: 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: Passenger Seatbelt Buckle Connector End View (C3738)
G12765509Courtesy of FORD MOTOR CO.
Harness Side

Circuit Pin
FR_PASS_SBLT_BCKL_SN_FD (Front Passenger Seatbelt Buckle Sensor Feed) - CR203 5 (GRAY/VIOLET)
GND (Ground) - RR137 6 (BLACK/WHITE)
Fig 2: Occupant Classification System Module (OCSM) Connector End View (C3285)
G12765510Courtesy of FORD MOTOR CO.
Harness Side

Circuit Pin
BTS VREF (Belt Tension Switch Voltage Reference) - LR142 5 (YELLOW/BLUE)
BTS SIG (Belt Tension Switch Signal) - VR210 6 (BLUE/BROWN)
Fig 3: Restraint Control Module-A (RCM-A) Connector End View (C310A)
G12765511Courtesy of FORD MOTOR CO.
Harness Side

Circuit Pin
  1. AX1: CHECK FOR DTC U3003:16 AND U3003:17 
    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 U3003:16 or U3003:17 retrieved DTC during the self-test? 
      Yes No
      REFER to the DTC Chart. Go to  AX2.
  2. AX2: RETRIEVE OCSM DIAGNOSTIC TROUBLE CODES (DTCS) 
    • Review the OCSM Diagnostic Trouble Codes (DTCs) retrieved from the OCSM self-test.
      Yes No
      This fault cannot be cleared until it is corrected and the DTC is no longer retrieved on-demand during the self-test.
      For DTC B0061:11, Go to  AX3.
      For DTC B0061:12, Go to  AX6.
      For DTC B0061:13, Go to  AX8.
      For DTC B0061:64 or B0061:1C, Go to  AX10.      		 This is an intermittent fault when present as a CMDTC only.
      Go to  AX13.
  3. AX3: CHECK THE BELT TENSION SENSOR (BTS) 
    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.
    NOTE: This pinpoint test step attempts to change the fault reported by the OCSM by inducing a different fault condition. If the fault reported changes, this indicates the OCSM is functioning correctly and is not the source of the fault.
    • Ignition OFF.
    • Passenger Seatbelt Buckle connector disconnected. (C3738)
    • Ignition ON, engine OFF.
    • Carry out the OCS self-test.
      NOTE: DIAGNOSTIC TIP: When viewing Diagnostic Trouble Codes (DTCs) with the Belt Tension Sensor (BTS) disconnected, an open circuit fault is normally retrieved. The Belt Tension Sensor (BTS) shares a connector with the passenger seatbelt buckle switch, and a passenger seatbelt buckle switch circuit fault will also be present in the RCM.
    • Is DTC B0061:11 retrieved on-demand during self-test? 
      Yes No
      Go to  AX4. INSTALL a new front passenger seatbelt buckle.
      REFER to the appropriate procedure in Seatbelt Systems article
      Go to  AX14.
  4. AX4: CHECK THE BELT TENSION SENSOR (BTS) CIRCUITS FOR A SHORT TO GROUND 
    • Ignition OFF.
    • OCSM connector disconnected. (C3285)
    • Measure the resistance between:
      (+) Passenger Seatbelt Buckle (C3738) Connector, Harness Side (-)
      FR_PASS_SBLT_BCKL_SN_FD - CR203 (GRAY/VIOLET) - Pin 5 Ground
    • Is the resistance greater than 10, 000 ohms? 
      Yes No
      Go to  AX5. REPAIR the circuit.
      Go to  AX14.
  5. AX5: CHECK THE BELT TENSION SENSOR (BTS) VREF CIRCUIT FOR AN OPEN 
    • Measure the resistance between:
      (+) OCSM (C3285) Connector, Harness Side (-) Passenger Seatbelt Buckle (C3738) Connector, Harness Side
      BTS VREF - LR142 (YELLOW/BLUE) - Pin 5 BTS VREF
    • Is the resistance less than 0.5 ohm? 
      Yes No
      Go to  AX12. REPAIR the circuit.
      Go to  AX14.
  6. AX6: CHECK THE BELT TENSION SENSOR (BTS) SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE 
    • Ignition OFF.
    • Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering in Supplemental Restraint System article.
    • Passenger Side Airbag (In-Line) Assembly connector disconnected. (C3519)
    • Passenger Seatbelt Buckle connector disconnected. (C3738)
    • OCSM connector disconnected. (C3285)
    • 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.
    • Measure the voltage between:
      (+) OCSM (C3285) Connector, Harness Side (-)
      BTS SIG - VR210 (BLUE/BROWN) - Pin 6 Ground
    • Is any voltage present? 
      Yes No
      REPAIR the circuit.
      Go to  AX14.      		 Go to  AX7.
  7. AX7: CHECK THE BELT TENSION SENSOR (BTS) GROUND CIRCUIT FOR AN OPEN 
    • Ignition OFF.
    • Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering in Supplemental Restraint System article.
    • RCM_A connector disconnected. (C310A)
    • RCM_B connector disconnected. (C310B)
    • Measure the resistance between:
      (+) Passenger Seatbelt Buckle (C3738) Connector, Harness Side (-)
      GND - RR137 (BLACK/WHITE) - Pin 6 Ground
    • Is the resistance less than 3 ohms? 
      Yes No
      Go to  AX11. REPAIR the circuit.
      Go to  AX14.
  8. AX8: CHECK THE BELT TENSION SENSOR (BTS) 
    NOTE: This pinpoint test step attempts to change the fault reported by the OCSM by inducing a different fault condition. If the fault reported changes, this indicates the OCSM is functioning correctly and is not the source of the fault.
    • Ignition OFF.
    • Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering in Supplemental Restraint System article.
    • Passenger Side Airbag (In-Line) Assembly connector disconnected. (C3519)
    • Passenger Seatbelt Buckle connector disconnected. (C3738)
    • Connect a 5 amp fused jumper wire between the following:
      Point A
      Passenger Seatbelt Buckle (C3738) Connector, Harness Side      		 Point B
      Passenger Seatbelt Buckle (C3738) Connector, Harness Side
      BTS SIG GND - RR137 - Pin 6
    • 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.
    • Carry out the OCS self-test.
    • Does the on-demand DTC change from B0061:13 to B0061:11? 
      Yes No
      REMOVE the fused jumper wire and INSTALL a new front passenger seatbelt buckle. REFER to: Front Seatbelt Buckle in Seatbelt Systems article
      Go to  AX14.      		 REMOVE the fused jumper wire.
      Go to  AX9.
  9. AX9: CHECK THE BELT TENSION SENSOR (BTS) SIGNAL CIRCUIT FOR AN OPEN 
    • Ignition OFF.
    • OCSM connector disconnected. (C3285)
    • Measure the resistance between:
      (+) Passenger Seatbelt Buckle (C3738) Connector, Harness Side (-) OCSM (C3285) Connector, Harness Side
      BTS SIG BTS SIG - VR210 - Pin 6
    • Is the resistance less than 0.5 ohm? 
      Yes No
      Go to  AX11. REPAIR the circuit.
      Go to  AX14.
  10. AX10: CHECK THE BELT TENSION SENSOR (BTS) SIGNAL CIRCUIT FOR A SHORT TO THE BELT TENSION SENSOR (BTS) VREF CIRCUIT 
    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.
    • OCSM connector disconnected. (C3285)
    • Passenger Seatbelt Buckle connector disconnected. (C3738)
    • Measure the resistance between:
      (+) Passenger Seatbelt Buckle (C3738) Connector, Harness Side (-) Passenger Seatbelt Buckle (C3738) Connector, Harness Side
      BTS VREF BTS SIG
    • Is the resistance greater than 10, 000 ohms? 
      Yes No
      Go to  AX11. REPAIR the circuit.
      Go to  AX14.
  11. AX11: CHECK BELT TENSION SENSOR (BTS) VOLTAGE OUTPUT 
    • Ignition OFF.
    • Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering in Supplemental Restraint System article.
    • OCSM connector connected. (C3285)
    • Passenger Side Airbag (In-Line) Assembly connector disconnected. (C3519)
    • Connect a 5 amp fused jumper wire between the following:
      Point A
      Passenger Seatbelt Buckle (C3738) Connector, Harness Side      		 Point B
      Passenger Seatbelt Buckle (C3738) Connector, Component Side
      BTS VREF BTS VREF
      GND - RR137 (BLACK/WHITE) - Pin 6 GND - RR137 - Pin 6
    • 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.
    • Measure the voltage between:
      (+) Passenger Seatbelt Buckle (C3738) Connector, Component Side (-)
      BTS SIG Ground
    • Does the voltage vary from approximately 0.95 volt with no tension applied to the sensor to approximately 3.8 volts with full tension applied to the sensor? 
      Yes No
      REMOVE the fused jumper wires.
      Go to  AX12.      		 REMOVE the fused jumper wires and INSTALL a new front passenger seatbelt buckle. REFER to: Front Seatbelt Buckle Seatbelt Systems article
      Go to  AX14.
  12. AX12: CONFIRM THE OCSM FAULT 
    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.
    NOTE: Make sure all OCS components, SRS electrical connectors and the RCM electrical connectors are connected before carrying out the self-test. If not, Diagnostic Trouble Codes (DTCs) will be recorded.
    • Ignition OFF.
    • 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 damage, pinched, cut or pierced wires.
      • Repair any concerns found. Refer to OEM GROUND DISTRIBUTION article, for schematic and connector information.
    • OCSM connector connected. (C3285)
    • Passenger Seatbelt Buckle connector connected. (C3738) (if previously disconnected).
    • If previously directed to disconnect Passenger Side Airbag (Inline), depower the SRS. REFER to: Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System article
    • Passenger Side Airbag (In-Line) Assembly connector connected. (C3519) (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) Depowering and Repowering Supplemental Restraint System article
    • Ignition ON, engine OFF.
    • Carry out the OCS self-test.
    • Is the original DTC retrieved on-demand during self-test? 
      Yes No
      CHECK OASIS for any applicable Technical Service Bulletins (TSBs). If a TSB exists for this concern, DISCONTINUE this test and FOLLOW TSB instructions. If no Technical Service Bulletins (TSBs) address this concern, INSTALL a new OCS sensor.
      REFER to: Occupant Classification System (OCS) Sensor - Vehicles With: Multi-Contour Seats Supplemental Restraint System article
      Go to  AX14.      		 In the process of diagnosing the fault, the fault condition has become intermittent. Do not install any new SRS components at this time. SRS components should only be installed when directed to do so in the pinpoint test.
      Go to  AX13.
  13. AX13: CHECK FOR AN INTERMITTENT FAULT 
    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.
    • Passenger Seatbelt Buckle connector disconnected. (C3738)
      • Inspect connector(s) (including any inline connectors) for loose or spread terminals and loose or frayed wire connections at terminals.
      • Inspect wire harness for any damage, pinched, cut or pierced wires.
      • Repair any concerns found. Refer to OEM GROUND DISTRIBUTION article, for schematic and connector information.
    • Passenger Seatbelt Buckle connector connected. (C3738)
    • Ignition ON, engine OFF.
    • Carry out the OCS self-test.
      Yes No
      The fault condition is now present. This fault cannot be cleared until it is corrected and the DTC is no longer retrieved on-demand during the self-test.
      For DTC B0061:11, Go to  AX3.
      For DTC B0061:12, Go to  AX6.
      For DTC B0061:13, Go to  AX8.
      For DTC B0061:64 or B0061:1C, Go to  AX10.      		 CHECK for causes of the intermittent fault. ATTEMPT to recreate the hard fault by flexing the wire harness and cycling the ignition frequently. ACTIVATE other system in the same wire harness. Do not install any new SRS components at this time. Only install SRS components when directed to do so in the pinpoint test. REPAIR any intermittent concerns found.
      Go to  AX14.
  14. AX14: 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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