501-20B Supplemental Restraint System 2014 Fiesta
Diagnosis and Testing Procedure revision date: 05/6/2013

Pinpoint Test - DTC: X

BXXXX:2B (any BXXXX DTC with a 2B failure type) Signal Cross Coupled


Refer to Wiring Diagrams Cell 46 for schematic and connector information.

Normal Operation and Fault Conditions

The RCM monitors all deployable device and sensor circuits for a signal cross coupled (short) between components. Signal cross coupled Diagnostic Trouble Codes (DTCs) are present when one or both circuits of a component are shorted to one or both circuits of another component. Signal cross coupled Diagnostic Trouble Codes (DTCs) will not set when the circuits of a single device are shorted together, a different DTC is present (for example, a DTC for circuit resistance below threshold). The RCM sends a message to the IPC to illuminate the airbag warning indicator. When a normal loop fault is present (one loop is either shorted to battery/ground, open circuit or low resistance), then signal cross coupled diagnostics are not active. Once the normal loop fault is repaired, the signal cross coupled diagnostics resume.



  DTC Fault Trigger Conditions


  DTC Description Fault Trigger Conditions
B0001:2B Driver Frontal Stage 1 Deployment Control: Signal Cross Coupled If the RCM detects a short between the driver airbag stage 1 circuits and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component.
B0002:2B Driver Frontal Stage 2 Deployment Control: Signal Cross Coupled If the RCM detects a short between the driver airbag stage 2 circuits and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component.
B0004:2B Driver Knee Bolster Deployment Control: Signal Cross Coupled If the RCM detects a short between the driver lower airbag circuits and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component.
B0010:2B Passenger Frontal Stage 1 Deployment Control: Signal Cross Coupled If the RCM detects a short between the passenger airbag stage 1 circuits and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component.
B0011:2B Passenger Frontal Stage 2 Deployment Control: Signal Cross Coupled If the RCM detects a short between the passenger airbag stage 2 circuits and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component.
B0050:2B Driver Seatbelt Sensor: Signal Cross Coupled If the RCM detects a short between the driver safety belt buckle switch circuits and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component.
B0052:2B Passenger Seatbelt Sensor: Signal Cross Coupled If the RCM detects a short between the passenger safety belt buckle switch circuits and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component.
B007E:2B Driver Seatbelt Pretensioner "C" Deployment Control: Signal Cross Coupled If the RCM detects a short between the driver safety belt retractor pretensioner circuits and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component.
B007F:2B Passenger Seatbelt Pretensioner "C" Deployment Control: Signal Cross Coupled If the RCM detects a short between the passenger safety belt retractor pretensioner circuits and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component.
B0082:2B Passenger Seatbelt Load Limiter Deployment Control: Signal Cross Coupled If the RCM detects a short between the passenger safety belt load limiter circuits and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component.
B00B5:2B Driver Seat Track Position Restraints Sensor: Signal Cross Coupled If the RCM detects a short between the LH seat position sensor circuits and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component.
B00C5:2B Passenger Seat Track Position Restraints Sensor: Signal Cross Coupled If the RCM detects a short between the RH seat position sensor circuits and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component.
B1404:2B Driver Side Airbag Deployment Control: Signal Cross Coupled If the RCM detects a short between the driver side airbag circuits and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component.
B1405:2B Driver Side Curtain Deployment Control 1: Signal Cross Coupled If the RCM detects a short between the LH side air curtain circuits and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component.
B1407:2B Passenger Side Airbag Deployment Control: Signal Cross Coupled If the RCM detects a short between the passenger side airbag circuits and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component.
B1408:2B Passenger Side Curtain Deployment Control 1: Signal Cross Coupled If the RCM detects a short between the RH side air curtain circuits and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component.


Possible Causes

Visual Inspection and Diagnostic Pre-Checks


PINPOINT TEST A : BXXXX:2B (ANY BXXXX DTC (DIAGNOSTIC TROUBLE CODE) WITH A 2B FAILURE TYPE) SIGNAL CROSS COUPLED
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, Diagnostic Trouble Codes (DTCs) may set.
NOTE: The SRS must be fully operational and free of faults before releasing the vehicle to the customer.
A1   RETRIEVE RCM (RESTRAINTS CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS)
  • Ignition ON.
  • Using a diagnostic scan tool, perform RCM self-test.

Were any signal cross coupled Diagnostic Trouble Codes (DTCs) retrieved on-demand during self-test?

Yes This fault cannot be cleared until it is corrected 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 Diagnostic Trouble Code (CMDTC) only. GO to A4


A2   CHECK THE AFFECTED CIRCUITS FOR A SIGNAL CROSS COUPLED FAULT
  • Ignition OFF.
  • Disconnect: RCM C310A and C310B.
  • Using the signal cross coupled Diagnostic Trouble Codes (DTCs) present on-demand, identify the affected SRS devices.
  • NOTE: Most signal cross coupled faults are due to connector and/or wiring harness damage. Carry out a thorough inspection of connector(s) and/or wiring harness for damage.

    Disconnect all of the affected SRS devices.
  • Using the following table, measure the resistance between the circuits of one affected SRS device to the other affected SRS device.
    • Example: If Diagnostic Trouble Codes (DTCs) B0001:2B and B0002:2B are being diagnosed, measure the resistance between circuit CR101 to circuits CR102 and RR102. Then measure the resistance between circuit RR101 to circuits CR102 and RR102.



    Device/Loop ( DTC ) Connector Circuit
    Driver airbag stage 1 (B0001:2B)
    • C216A-1
    • C216A-2
    • CR101 (WH)
    • RR101 (OG)
    Driver airbag stage 2 (B0002:2B)
    • C216B-1
    • C216B-2
    • CR102 (BN)
    • RR102 (BU)
    Driver lower airbag (B0004:2B)
    • C2432-1
    • C2432-2
    • CR139 (VT/WH)
    • RR139 (YE)
    Passenger airbag stage 1 (B0010:2B)
    • C256A-1
    • C256A-2
    • CR103 (GY/BU)
    • RR103 (VT/GN)
    Passenger airbag stage 2 (B0011:2B)
    • C256B-1
    • C256B-2
    • CR104 (YE/GY)
    • RR104 (WH/BU)
    Driver safety belt buckle switch (B0050:2B)
    • C3065-2
    • CR201 (GN/BU)
    Passenger safety belt buckle switch (B0052:2B)
    • C3066-2
    • CR202 (BN/GN)
    Driver safety belt retractor pretensioner (B007E:2B)
    • C323-1
    • C323-2
    • RR146 (BU/BN)
    • CR146 (GY/VT)
    Passenger safety belt retractor pretensioner (B007F:2B)
    • C303-1
    • C303-2
    • RR147 (YE/VT)
    • CR147 (GN/OG)
    Passenger safety belt adaptive load limiter (B0082:2B)
    • C389-1
    • C389-2
    • CR122 (WH/OG)
    • RR122 (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 airbag (B1404:2B)
    • C367-1
    • C367-3
    • RR105 (GY/YE)
    • CR105 (GN/BU)
    LH side air curtain (B1405:2B)
    • C9018-1
    • C9018-2
    • CR109 (BN/BU)
    • RR109 (BU/GN)
    Passenger side airbag (B1407:2B)
    • C337-1
    • C337-3
    • RR106 (YE/OG)
    • CR106 (VT/GY)
    RH side air curtain (B1408:2B)
    • C9019-1
    • C9019-2
    • CR111 (BN/WH)
    • RR111 (YE/VT)



Are the resistances greater than 10,000 ohms between the affected circuits?

Yes GO to A3
No REPAIR the affected circuits.
Refer to Wiring Diagrams Cell 5 for schematic and connector information.
GO to A5


A3   CONFIRM THE RCM (RESTRAINTS CONTROL MODULE) FAULT

NOTE: Make sure all SRS components and the RCM electrical connectors are connected before carrying out the self-test. If not, Diagnostic Trouble Codes (DTCs) will be recorded.

  • 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.
    • inspect RCM C310A and C310B Connector Position Assurance (CPA) lever/lock for correct operation.
    • repair any concerns found.
      Refer to Wiring Diagrams Cell 5 for schematic and connector information.
  • Connect all previously disconnected restraint system component(s).
  • Connect: RCM C310A and C310B.
  • Ignition ON.
  • Using a diagnostic scan tool, perform RCM self-test.

Were any signal cross coupled Diagnostic Trouble Codes (DTCs) retrieved on-demand during self-test?

Yes 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 RCM .
REFER to: Restraints Control Module (RCM) (501-20B Supplemental Restraint System, Removal and Installation).
GO to A5
No 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 A4


A4   CHECK FOR AN INTERMITTENT FAULT

NOTE: Most cross link faults are due to connector and/or wiring harness damage. Carry out a thorough inspection of connector(s) and/or wiring harness for damage.

  • Ignition OFF.
  • Disconnect all of the affected SRS devices.
    Refer to Wiring Diagrams Cell 46 for schematic and connector information.
  • Inspect the wiring harness(es) for any type of damage. If damage is found, repair as necessary and
    Refer to Wiring Diagrams Cell 5 for schematic and connector information.
  • Ignition ON.
  • Using a diagnostic scan tool, perform RCM self-test.

Were any signal cross coupled Diagnostic Trouble Codes (DTCs) retrieved on-demand during self-test?

Yes This fault cannot be cleared until it is corrected and the DTC is no longer retrieved on-demand during self-test. GO to A2
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 and cycling the ignition frequently. 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 A5


A5   CHECK FOR ADDITIONAL SRS (SUPPLEMENTAL RESTRAINT SYSTEM) 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).
  • Ignition ON.
  • NOTE: When selecting Restraints from the Self Test menu, DTCs are retrieved from the RCM and OCSM .

    Using a diagnostic scan tool, perform Restraints self-test.

Are any RCM and/or OCSM Diagnostic Trouble Codes (DTCs) retrieved on-demand during self-test?

Yes Do not clear any Diagnostic Trouble Codes (DTCs) until all Diagnostic Trouble Codes (DTCs) have been resolved. DIAGNOSE and REPAIR the RCM and/or OCSM Diagnostic Trouble Codes (DTCs).
REFER to: Airbag Supplemental Restraint System (SRS) (501-20B Supplemental Restraint System, Diagnosis and Testing).
No CLEAR all RCM and OCSM Continuous Memory Diagnostic Trouble Codes (CMDTCs). PROVE OUT the SRS . The repair is complete. RETURN the vehicle to the customer.





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