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 |
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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
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) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
Were any signal cross coupled Diagnostic Trouble Codes (DTCs) retrieved on-demand during self-test?
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A2 CHECK THE AFFECTED CIRCUITS FOR A SIGNAL CROSS COUPLED FAULT | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
Are the resistances greater than 10,000 ohms between the affected circuits?
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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.
Were any signal cross coupled Diagnostic Trouble Codes (DTCs) retrieved on-demand during self-test?
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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.
Were any signal cross coupled Diagnostic Trouble Codes (DTCs) retrieved on-demand during self-test?
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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.
Are any RCM and/or OCSM Diagnostic Trouble Codes (DTCs) retrieved on-demand during self-test?
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Removal
NOTE: Removal steps in this procedure may contain installation details.
Remove the brake shoes.