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Home >> Mercury >> 2008 >> Milan Base, 2.3 Z, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 1401 (Supplemental Restraint System) >> Diagnosis And Testing >> Air Bag And Safety Belt PRETENSIONER Supplemental Restraint System (SRS) >> Pinpoint Tests >> Pinpoint Test P: DTC B2792 - Cross Link Between Firing Loops >> Pinpoint Test P: DTC B2792 - Cross Link Between Firing Loops Fault

Pinpoint Test P: DTC B2792 - Cross Link Between Firing Loops Fault

WARNING: This page is about a different car, the 2009 Mercury Milan, 2009 Lincoln MKZ, and 2009 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
WARNING: Never probe the electrical connectors on air bag, safety canopy or side air curtain modules. Failure to follow this instruction may result in the accidental deployment of these modules, which increases the risk of serious personal injury or death.
WARNING: Never probe the electrical connectors on safety belt buckle/retractor pretensioners or adaptive load limiting retractors. Failure to follow this instruction may result in the accidental deployment of the safety belt pretensioners or adaptive load limiting retractors, which increases the risk of serious personal injury or death.
NOTE: Use the correct probe adapter(s) from the Flex Probe Kit when making measurements. Failure to use the correct probe adapter(s) may damage 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: Supplemental restraint system (SRS) components should only be disconnected or reconnected when instructed to do so within a pinpoint test step. Failure to follow this instruction may result in incorrect diagnosis of the SRS. 
NOTE: The SRS must be fully operational and free of faults before releasing the vehicle to the customer.
  1. P1 CHECK FOR CONTINUOUS AND ON-DEMAND DTCs 
    • Enter the following diagnostic mode on the diagnostic tool: Self Test - RCM
    • Enter the following diagnostic mode on the diagnostic tool: DataLogger - RCM - View and Record All B2792 Fault PIDs
      • Refer to PID list in Normal Operation to view B2792 fault PIDs.
    • Do any RCM on-demand DTC B2792 fault PIDs indicate a fault? 
    1. 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  P2.
    2. NO  : This is an intermittent fault when present as a continuous memory DTC only (DTC not retrieved on demand). The fault condition is not present at this time. Go to  P4.
  2. P2 CHECK DEPLOYABLE CIRCUITS FOR A CROSS LINK FAULT 
    • Key in OFF position.
    • Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering .
    • Disconnect: RCM C310a and C310b
    • Disconnect ALL of the affected  deployable devices.
    • Using the fault PIDs recorded and the following table, measure the resistance between the circuits of the affected deployable devices.
      DEPLOYABLE DEVICES

      Fault PID (loop/deployable device) Connector - Pin Circuit
      2792_31_OD (Airbag Driver Front Loop #1)
      • C310a-3
      • C310a-4
      • RR101 (YE/GN)
      • CR101 (VT/BN)
      2792_30_OD (Airbag Driver Front Loop #2)
      • C310a-15
      • C310a-16
      • RR102 (WH)
      • CR102 (BU)
      2792_29_OD (Airbag Passenger Front Loop #1)
      • C310a-1
      • C310a-2
      • CR103 (GY/BU)
      • RR103 (VT/GN)
      2792_28_OD (Airbag Passenger Front Loop #2)
      • C310a-5
      • C310a-6
      • CR104 (YE/GY)
      • RR104 (WH/BU)
      2792_13_OD (Side Airbag Driver)
      • C310b-7
      • C310b-8
      • RR105 (GY/YE)
      • CR105 (GN/BU)
      2792_12_OD (Side Airbag Passenger)
      • C310b-9
      • C310b-10
      • CR106 (VT/GY)
      • RR106 (YE/OG)
      2792_9_OD (A-B or A-C pillar Curtain, Driver Side)
      • C310b-21
      • C310b-22
      • CR109 (BN/BU)
      • RR109 (BU/GN)
      2792_8_OD (A-B or A-C pillar Curtain, Passenger Side)
      • C310b-1
      • C310b-2
      • CR111 (BN/WH)
      • RR111 (YE/VT)
      2792_27_OD (Pretensioner Driver)
      • C310b-31
      • C310b-32
      • CR120 (BU/OG)
      • RR120 (BN/GN)
      2792_26_OD (Pretensioner Passenger)
      • C310b-33
      • C310b-34
      • RR121 (VT)
      • CR121 (GY/VT)
    • Are the resistances greater than 10,000 ohms between the affected circuits? 
    1. YES  : Go to  P3.
    2. NO  : REPAIR the affected circuits. Go to  P5.
  3. P3 CONFIRM THE RCM FAULT 
    NOTE: Make sure all restraint system components, sensor electrical connectors and the RCM electrical connectors are connected before carrying out the on-demand self test. If not, erroneous DTCs will be recorded.
    • Connect: RCM C310a and C310b
    • Connect: All Previously Disconnected SRS Components
    • Repower the SRS. Do not  prove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering .
    • Enter the following diagnostic mode on the diagnostic tool: Self Test - RCM
    • Enter the following diagnostic mode on the diagnostic tool: DataLogger - RCM - View and Record All B2792 Fault PIDs
      • Refer to PID list in Normal Operation to view B2792 fault PIDs.
    • Does the original RCM on-demand DTC B2792 fault PID indicate a fault? 
    1. YES  : INSTALL a new RCM. REFER to Restraints Control Module (RCM) . Go to  P5.
    2. NO  : In the process of diagnosing the fault, the fault condition has become intermittent. CHECK for causes of the intermittent fault in the areas previously worked in, particularly the pins and terminals of electrical connectors that were disconnected. ATTEMPT to recreate the hard fault by flexing the wire harness and cycling the ignition key frequently. 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.  REPAIR any intermittent wiring, terminal or connector concerns found. Go to  P5.
  4. P4 CHECK FOR AN INTERMITTENT FAULT 
    • Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering .
    • If a cross link fault for driver air bag loop 1 or loop 2 is present continuous, remove the driver air bag module. Refer to Driver Air Bag Module .
    • If a cross link fault for passenger air bag module loop 1 or loop 2 is present continuous, remove the passenger air bag module. Refer to Passenger Air Bag Module .
    • If a cross link fault for driver seat side air bag is present continuous, disconnect the driver seat side air bag module C327.
    • If a cross link fault for passenger seat side air bag is present continuous, disconnect the passenger seat side air bag module C313.
    • If a cross link fault for driver side air curtain module is present continuous, disconnect the driver side air curtain module C3055.
    • If a cross link fault for passenger side air curtain module is present continuous, disconnect the passenger side air curtain module C3056.
    • If a cross link fault for driver safety belt retractor pretensioner is present continuous, disconnect the driver safety belt retractor pretensioner C323.
    • If a cross link fault for passenger safety belt retractor pretensioner is present continuous, disconnect the passenger safety belt retractor pretensioner C3202.
    • Repower the SRS. Do not  prove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering .
    • Key in ON position.
    • Enter the following diagnostic mode on the diagnostic tool: Self Test - RCM
    • Enter the following diagnostic mode on the diagnostic tool: DataLogger - RCM - View and Record All B2792 Fault PIDs
      • Refer to PID list in Normal Operation to view B2792 fault PIDs.
    • Do any on-demand DTC B2792 fault PIDs indicate a fault? 
    1. 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  P2.
    2. NO  : The fault is not present and cannot be recreated at this time.

      CHECK for causes of the intermittent fault. ATTEMPT to recreate the hard fault by flexing the wire harness, cycling the ignition key frequently and rotating the steering wheel (driver air bag module fault). 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.  REPAIR any intermittent wiring, terminal or connector concerns found. Go to  P5.

  5. P5 CHECK FOR ADDITIONAL SRS DTCs 
    • Key in OFF position.
      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.
    • Reconnect all SRS components (if previously disconnected).
    • Key in ON position.
    • Enter the following diagnostic mode on the diagnostic tool: Self Test - Restraints
    • Are any RCM and/or OCSM DTCs retrieved indicating a fault? 
    1. YES  : Do not clear any DTCs until all DTCs have been resolved. Go to the Supplemental Restraint System (SRS) DTC Chart  for pinpoint test direction.
    2. NO  : CLEAR all RCM and OCSM DTCs. PROVE OUT the SRS. REPAIR is complete. RETURN the vehicle to the customer.
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