Ford Fiesta Quiz
Body and Paint

Pinpoint Test - DTC: X. Diagnosis and Testing

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~11min read

BXXXX:2B (any BXXXX DTC with fault type 2B) Signal Crosscoupling


For circuit and connector information, refer to Wiring Diagrams Cell 46.

Normal Operation and Fault Symptoms

The RCM monitors all deployment devices and sensor circuits for signal crosscoupling (shorts) between components. Signal crosscoupling DTCs are present when one or both circuits of a component are shorted to one or both circuits of another component. Signal crosscoupling DTCs are not set when the circuits of one device are shorted to each other and another DTC is present (for example, a DTC for circuit resistance below the threshold). The RCM sends a message to the IPC to illuminate the airbag indicator. When a general circuit fault is present (one circuit shorted to battery or ground, or an open circuit or low resistance), signal crosscoupling diagnostics are not active. After the general circuit fault is corrected, signal crosscoupling diagnostics resume.


DTC Fault Trigger Conditions


Trouble Code Description Fault Trigger Conditions
B0001:2B Driver Frontal Stage 1 Deployment Control: Signal Cross-Circuit If the RCM detects a short between the driver stage 1 airbag circuits and another SRS component circuit, it sets this DTC and the DTC of the corresponding SRS component.
B0002:2B Driver Frontal Stage 2 Deployment Control: Signal Cross-Circuit If the RCM detects a short between the driver stage 2 airbag circuits and another SRS component circuit, it sets this DTC and the DTC of the corresponding SRS component.
B0004:2B Driver Knee Airbag Deployment Control: Signal Cross-Circuit If the RCM detects a short between the driver front airbag circuits and the circuits of another SRS component, it sets this DTC and the DTC for the corresponding SRS component.
B0010:2B Passenger Side Front Stage 1 Deployment Control: Signal Cross Coupled If the RCM detects a short between the passenger stage 1 airbag circuits and another SRS component circuit, it sets this DTC and the DTC of the corresponding SRS component.
B0011:2B Passenger Side Front Stage 2 Deployment Control: Signal Cross Coupled If the RCM detects a short between the passenger stage 2 airbag circuits and another SRS component circuit, it sets this DTC and the DTC of the corresponding SRS component.
B0050:2B Driver Seat Belt Sensor: Signal Cross Coupled If the RCM detects a short between the driver seatbelt buckle switch circuits and the circuits of another SRS component, it sets this DTC and the DTC for the corresponding SRS component.
B0052:2B Passenger Seat Belt Sensor: Signal Cross Coupled If the RCM detects a short between the passenger seatbelt buckle switch circuits and the circuits of another SRS component, it sets this DTC and the DTC for the corresponding SRS component.
B007E: 2B Driver Seat Belt Pretensioner Deployment Control "C": Signal Cross Coupled If the RCM detects a short circuit between the driver seat belt retractor pretensioner circuit and a circuit of another SRS component, it sets this DTC and the DTC of the corresponding SRS component.
B007F: 2B Passenger Seat Belt Pretensioner Deployment Control "C": Signal Cross-Coupling If the RCM detects a short between the passenger seatbelt pretensioner circuits and the circuits of another SRS component, it sets this DTC and the DTC for the corresponding SRS component.
B0082:2B Passenger Seat Belt Load Limiter Deployment Control: Cross-Communication Signal If the RCM detects a short between the passenger seatbelt load limiter circuits and the circuits of another SRS component, it sets this DTC and the DTC for the corresponding SRS component.
B00B5:2B Driver Seat Track Position Sensor: Signal Cross Coupled If the RCM detects a short between the left seat position sensor circuits and the circuits of another SRS component, it sets this DTC and the DTC for the corresponding SRS component.
B00K5:2B Passenger Seat Track Position Sensor: Signal Cross Coupled If the RCM detects a short between the right seat position sensor circuits and the circuits of another SRS component, it sets this DTC and the DTC for the corresponding SRS component.
B1404:2B Driver Side Airbag Deployment Control: Signal Cross-Coupling If the RCM detects a short circuit between the driver side airbag circuits and a circuit of another SRS component, it sets this DTC and the DTC of the corresponding SRS component.
B1405:2B Driver Side Curtain 1 Deployment Control: Signal Cross-Coupling If the RCM detects a short between the left side airbag circuits and the circuits of another SRS component, it sets this DTC and the DTC for the corresponding SRS component.
B1407:2B Driver Side Air Bag Deployment Control: Signal Cross Coupled If the RCM detects a short circuit between the passenger side airbag circuits and a circuit of another SRS component, it sets this DTC and the DTC of the corresponding SRS component.
B1408:2B Passenger Side Curtain 1 Deployment Control: Signal Cross-Coupling If the RCM detects a short between the right side airbag circuits and the circuits of another SRS component, it sets this DTC and the DTC for the corresponding SRS component.

Possible Causes

  • Wiring, Terminals or Connectors
  • RCM

Visual Inspection and Preliminary Diagnosis

  • Inspect the applicable wiring harness for damage, if accessible.

PINPOINT TEST A: BXXXX:2B (ANY BXXXX DTC WITH FAULT TYPE 2B) SIGNAL CROSSCOUPLING
NOTE: Most concerns are related to connector and/or wiring issues. Perform a thorough inspection and check before proceeding to the Pinpoint Test.
NOTE: Only disconnect or reconnect SRS components when instructed to do so in the Pinpoint Test step. Failure to follow this instruction may result in an incorrect SRS diagnosis.
NOTE: Always verify the correct SRS component is installed. Parts released for other vehicles may be incompatible even if they appear physically similar. Check the part number listed in the Ford parts catalog to confirm the correct component is installed. If an incorrect SRS component is installed, diagnostic trouble codes (DTCs) may be set.
NOTE: Before returning the vehicle to the customer, the SRS must be fully functional and operating correctly.
A1 REMOVE RCM (RESTRAINTS CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS)
  • WARNING: Before starting any service procedure in this section, refer to the Safety Warnings in Section 100-00 General Information. Failure to follow this instruction may result in serious personal injury.
    REFER TO: Pyrotechnic Device Handling Precautions (100-00 General Information, Description and Operation).
  • The ignition is on.
  • Using the diagnostic scanner, perform the RCM self-test.

Were any cross-channel Diagnostic Trouble Codes (DTCs) retrieved on demand during the self-test?
Yes This fault cannot be cleared until it is repaired and the DTC is no longer retrieved during the on-demand self-test. GO to A2
No This is an intermittent fault when present as a Continuous Memory DTC (CMDTC) only. GO to A4
A2 CHECK THE AFFECTED CIRCUITS FOR SIGNAL CROSSCOUPLING FAULT.
  • Ignition OFF.
  • De-power the SRS.
    REFER to: Supplemental Restraint System (SRS) Disabling and Re-enabling (501-20B Supplemental Restraint System, General Procedures).
  • Disconnect: RCM C310A and C310B.
  • Using the cross-channel Diagnostic Trouble Codes (DTCs) that were retrieved on demand, identify the affected SRS devices.
  • NOTE: Most cross-channel faults are caused by connector and/or harness damage. Carefully inspect the connector(s) and/or harness for damage. Disconnect all affected SRS devices.
  • Using the following table, measure the resistance between the circuits of one affected SRS device and the other affected SRS device.
    • Example: If Diagnostic Trouble Codes (DTCs) B0001:2B and B0002:2B are retrieved, measure the resistance between circuit CR101 and circuits CR102 and RR102. Then measure the resistance between circuit RR101 and circuits CR102 and RR102.
    Device/Circuit (DTC) Connector Circuit
    Driver Air Bag, Stage 1 (B0001:2B)
    • C216A-1
    • C216A-2
    • CR101 (White)
    • RR101 (OG)
    Driver Air Bag, Stage 2 (B0002:2B)
    • C216B-1
    • C216B-2
    • CR102 (BN)
    • RR102 (BU)
    Driver Front Airbag (B0004:2B)
    • C2432-1
    • C2432-2
    • CR139 (VT/WH)
    • 139 (Yellow)
    Passenger Air Bag, Stage 1 (B0010:2B)
    • C256A-1
    • C256A-2
    • CR103 (GY/Blue)
    • RR103 (VT/GN)
    Passenger Air Bag, Stage 2 (B0011:2B)
    • C256B-1
    • C256B-2
    • CR104 (Yellow/Grey)
    • RR104 (White/Blue)
    Driver Seatbelt Buckle Switch (B0050:2B)
    • C3065-2
    • CR201 (Green/Blue)
    Passenger Seatbelt Buckle Switch (B0052:2B)
    • C3066-2
    • CR202 (BN/GN)
    Driver Seatbelt Pretensioner (B007E:2B)
    • C323-1
    • C323-2
    • 146 (BU/BN)
    • CR146 (GY/WH)
    Passenger Seatbelt Pretensioner (B007F:2B)
    • C303-1
    • C303-2
    • RR147 (YE/VT)
    • CR147 (GN/OG)
    Passenger Seat Belt Adaptive Load Limiter (B0082:2B)
    • C389-1
    • C389-2
    • CR122 (White/Orange)
    • 122 (BN)
    Driver Seat Position Sensor (B00B5:2B)
    • C356-2
    • VR215 (YE/VT)
    Passenger Seat Position Sensor (B00C5:2B)
    • C3617-2
    • VR216 (GN/OG)
    Driver Side Air Bag (B1404:2B)
    • C367-1
    • C367-3
    • 105 (Grey/Yellow)
    • CR105 (Green/Blue)
    Left Side Air Curtain (B1405:2B)
    • C9018-1
    • C9018-2
    • CR109 (WH/BN)
    • RR109 (BU/GN)
    Passenger Side Air Bag (B1407:2B)
    • C337-1
    • C337-3
    • RR106 (YE/OG)
    • CR106 (VT/GY)
    Right Side Air Curtain (B1408:2B)
    • C9019-1
    • C9019-2
    • CR111 (BK/WH)
    • RR111 (YE/VT)

Are the resistances between the affected circuits greater than 10,000 ohms?
Yes GO to A3
No REPAIR the damaged circuits.
For schematics and connector information, refer to Wiring Diagrams Cell 5.
GO to A5
A3 CONFIRM RCM (RESTRAINTS CONTROL MODULE) FAULT
  • Before reconnecting any previously disconnected SRS component:
    • inspect the connector(s) (including any integral connectors) for pushed-out, loose or spread terminals, and loose or chafed wire connections at the terminals.
    • Inspect the wiring harness for damage, pinching, cuts or punctures in the wires.
    • check the RCM C310A and C310B connector position assurance (CPA) lever/latch for proper operation.
    • repair any problems found.
      Refer to Wiring Diagrams Cell 5 for schematic and connector information.
  • Connect all previously disconnected restraints system components.
  • Connect: RCM C310A and C310B.
  • Reset the SRS. Do not check the SRS at this time.
    REFER TO: Supplemental Restraint System (SRS) Disarming and Rearming (501-20B Supplemental Restraint System, General Procedures).
  • The ignition is on.
  • Using the diagnostic scanner, perform the RCM self-test.

Were any cross-channel Diagnostic Trouble Codes (DTCs) retrieved on demand during the self-test?
Yes CHECK in OASIS for any applicable Technical Service Bulletins (TSBs). If a TSB exists for this concern, STOP this test and FOLLOW the TSB instructions. If no TSB applies to this concern, INSTALL a new RCM.
REFER TO: Restraints Control Module (RCM) (501-20B Supplemental Restraint System, Removal and Installation).
GO to A5
No During the diagnostic procedure the condition became intermittent. Do not install new SRS components at this time. Install SRS components only if directed by the pinpoint test. GO to A4
A4 CHECK FOR INTERMITTENT FAULT
  • Ignition OFF.
  • De-power the SRS.
    REFER to: Supplemental Restraint System (SRS) Disabling and Re-enabling (501-20B Supplemental Restraint System, General Procedures).
  • Disconnect all affected SRS devices.
    For wiring diagrams and connector information, refer to Wiring Diagrams Cell 46.
  • Inspect the wiring harness for damage of any kind. If damage is found, repair as necessary and
    For schematics and connector information, refer to Wiring Diagrams Cell 5.
  • Reset the SRS. Do not check the SRS at this time.
    REFER TO: Supplemental Restraint System (SRS) Disarming and Rearming (501-20B Supplemental Restraint System, General Procedures).
  • The ignition is on.
  • Using the diagnostic scanner, perform the RCM self-test.

Were any cross-channel Diagnostic Trouble Codes (DTCs) retrieved on demand during the self-test?
Yes This fault cannot be cleared until it is repaired and the DTC is no longer retrieved on demand during the self-test. GO to A2
No The fault is not present and cannot be recreated at this time. CHECK for causes of intermittent fault. Attempt to recreate the intermittent fault by flexing the wiring harness and performing repeated ignition cycles. At this time do not install any new SRS components. Install SRS components only if directed by the pinpoint test. GO to A5
A5 CHECK for SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DIAGNOSTIC TROUBLE CODES (DTCS)
  • Ignition OFF.
  • Reconnect all SRS components (if previously disconnected).
  • If previously instructed to disable the SRS, re-enable the SRS. Do not check the SRS at this time.
    Refer to: Supplemental Restraint System (SRS) Disabling and Arming (501-20B Supplemental Restraint System, General Procedures).
  • The ignition is on.
  • NOTE: When Restraints is selected in the Self Test menu, DTCs are retrieved from the RCM and OCSM. Using the diagnostic scanner, perform the Restraints Self Test.

Are any RCM and/or OCSM Diagnostic Trouble Codes (DTCs) retrieved on demand during the self-test?
Yes Do not clear any Diagnostic Trouble Codes (DTCs) until all DTCs have been resolved. DIAGNOSE and REPAIR the RCM and/or OCSM DTCs.
REFER TO: Supplemental Restraint System (SRS) (501-20 Supplemental Restraint System).
No CLEAR all RCM and OCSM continuous memory diagnostic trouble codes (CMDTCs). VERIFY SRS. Repair is complete. RETURN the vehicle to the customer.

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