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Home >> Ford >> 2000 >> Taurus LX, 3.0 2, AX4N >> Repair and Diagnosis >> External Pages >> Different car >> Section 550 (Supplemental Inflatable Restraint System) >> Diagnosis And Testing >> Pinpoint Tests - Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS) >> Pinpoint Tests >> Pinpoint Test S: LFC 51 /DTC B2691 - Driver Safety Belt Buckle Switch Circuit Fault >> Pinpoint Test S: LFC 51/DTC B2691 - Driver Safety Belt Buckle Switch Circuit Fault

Pinpoint Test S: LFC 51/DTC B2691 - Driver Safety Belt Buckle Switch Circuit Fault

WARNING: This page is about a different car, the 2006 Mercury Mariner and 2006 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION: When installing a new restraints control module (RCM), always make sure the correct RCM is being installed. The RCM 40-pin connector is keyed differently for vehicles with safety canopies and side air bags than the 40-pin connector for vehicles without safety canopies and side air bags. Do not force the 40-pin connector onto the RCM. If the connector is forced onto the RCM, damage to the RCM and/or connector will occur.
NOTE: Most faults are due to connector and/or wiring concerns. Carry out a thorough Inspection and Verification  before proceeding with the Pinpoint Test.
  1. S1 CHECK FOR CONTINUOUS OR ON-DEMAND DTCs 
    WARNING:
    1. Restraint system diagnostic tools are for service only. Tools must be removed prior to operating the vehicle over the road. Failure to remove restraint system diagnostic tools could result in injury and possible violation of vehicle safety standards.
    2. Do not handle, move or change the original horizontal mounting position of the restraints control module (RCM) while the RCM is connected and the ignition switch is ON. Failure to follow these instructions may result in the inadvertent deployment of the safety canopy and risk of personal injury.
    3. Never probe the connectors on the air bag module. Doing so can result in air bag deployment, which can result in personal injury.
    4. The safety belt pretensioner is a pyrotechnic device. Always wear safety glasses when repairing an air bag equipped vehicle and when handling a safety belt buckle pretensioner or safety belt retractor pretensioner. Never probe a pretensioner electrical connector. Doing so could result in pretensioner or air bag deployment and could result in personal injury.
    5. Never probe the electrical connector on a safety canopy module. Doing so can result in safety canopy deployment.
    NOTE:
    1. If a seat equipped with a supplemental restraint system (SRS) component is being serviced, the SRS must be depowered.
    2. After diagnosing or repairing an SRS, the restraint system diagnostic tools must be removed before operating the vehicle over the road  .
    3. The SRS must be fully operational and free of faults before releasing the vehicle to the customer.
    • Enter the following diagnostic mode on the scan tool: On-Demand Self Test.
    • Enter the following diagnostic mode on the scan tool: Retrieve/Record Continuous DTCs.
    • Was the DTC B2691 retrieved during the on-demand self test? 

    Yes:  This is a hard fault. The fault condition is still present. This fault cannot be cleared until it is corrected and the DTC is no longer retrieved during the on-demand self test. GO to  S2.

    No:  This is an intermittent fault. The fault condition is not present at this time. GO to  S7.

  2. S2 CHECK CIRCUIT 85 (BN/LB) FOR AN OPEN BETWEEN THE RCM AND THE DRIVER SAFETY BELT BUCKLE SWITCH 
    • Key in OFF position.
    • Depower the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
    • Disconnect: RCM C2041a and C2041b.
    • Disconnect: Driver Safety Belt Buckle Switch C3065.
    • Measure the resistance between RCM C2041b-25, circuit 85 (BN/LB), harness side and driver safety belt buckle switch C3065-1, circuit 85 (BN/LB), harness side.
      Fig 1: Checking Circuit 85 (BN/LB) For Open Between RCM & Driver Safety Belt Buckle Switch
      G04622707Courtesy of FORD MOTOR CO.
    • Is the resistance less than 0.5 ohm? 

    Yes:  GO to  S3.

    No:  REPAIR circuit 85 (BN/LB). GO to  S8.

  3. S3 CHECK CIRCUIT 1203 (BK/LB) FOR AN OPEN 
    • Measure the resistance between driver safety belt buckle switch C3065-2, circuit 1203 (BK/LB), harness side and ground.
      Fig 2: Checking Circuit 1203 (BK/LB) For Open
      G04622708Courtesy of FORD MOTOR CO.
    • Is the resistance less than 0.5 ohm? 

    Yes:  GO to  S4.

    No:  REPAIR circuit 1203 (BK/LB). GO to  S8.

  4. S4 CHECK CIRCUIT 85 (BN/LB) FOR A SHORT TO VOLTAGE 
    • Repower the system. Do not  prove out the system at this time. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
    • Key in ON position.
    • Measure the voltage between driver safety belt buckle switch C3065-1, circuit 85 (BN/LB), harness side and ground.
      Fig 3: Checking Circuit 85 (BN/LB) For Short To Voltage
      G04622709Courtesy of FORD MOTOR CO.
    • Is the voltage less than 0.2 volt? 

    Yes:  GO to  S5.

    No:  REPAIR circuit 85 (BN/LB). GO to  S8.

  5. S5 CHECK THE DRIVER SAFETY BELT BUCKLE SWITCH 

    Yes:  GO to  S6.

    No:  Fault corrected. GO to  S8.

  6. S6 CONFIRM THE RCM FAULT 
    NOTE: Make sure all restraint system diagnostic tools, sensor electrical connector and the RCM electrical connector are connected before carrying out the on-demand self test. If not, erroneous DTCs will be recorded.

    Yes:  INSTALL a new RCM. REFER to RESTRAINTS CONTROL MODULE (RCM) . GO to  S8.

    No:  CHECK for causes of the intermittent fault. ATTEMPT to recreate the hard fault by flexing the wire harness and cycling the ignition key frequently. REPAIR any intermittent concerns found. GO to  S8.

  7. S7 CHECK FOR AN INTERMITTENT FAULT 
    • Key in OFF position.
    • Enter the following diagnostic mode on the scan tool: On-Demand Self Test.
    • Was DTC B2691 retrieved during the on-demand self test? 

    Yes:  This is a hard fault. The fault condition is now present. This fault cannot be cleared until it is corrected and the DTC is no longer retrieved during the on-demand self test. GO to  S2.

    No:  CHECK for causes of the intermittent fault. ATTEMPT to recreate the hard fault by flexing the wire harness and cycling the ignition key frequently. REPAIR any intermittent concerns found. GO to  S8.

  8. S8 CHECK FOR ADDITIONAL DTCs 
    • Refer to the continuous DTCs recorded during Step  S1.
    • Were any continuous DTCs retrieved during Step   S1 ? 

    Yes:  Do not clear any DTCs until all DTCs have been resolved. GO to the RESTRAINTS CONTROL MODULE (RCM) DIAGNOSTIC TROUBLE CODE (DTC) TABLE  for pinpoint test direction.

    No:  RECONNECT the system. If previously directed to deactivate the system, REACTIVATE the system. REFER to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEACTIVATION AND REACTIVATION . REPOWER the system. REFER to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING . PROVE OUT the system. CLEAR all DTCs.

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