BXXXX:2B, BXXXX:81 (any BXXXX DTC with a 2B failure type, or any impact sensor with an 81 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) do 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 knee 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. |
| B0013:2B | Passenger Knee Bolster Deployment Control: Signal Cross Coupled | If the RCM detects a short between the passenger knee airbag 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 seatbelt sensor 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 seatbelt sensor circuits and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component. |
| B0070:2B | Driver Seatbelt Pretensioner "A" Deployment Control: Signal Cross Coupled | If the RCM detects a short between the driver seatbelt anchor pretensioner circuits and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component. |
| B0072:2B | Passenger Seatbelt Pretensioner "A" Deployment Control: Signal Cross Coupled | If the RCM detects a short between the passenger seatbelt anchor pretensioner 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 seatbelt 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 seatbelt 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 seatbelt 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 driver seat position sensor circuit 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 passenger seat position sensor circuit and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component. |
| B11CF:2B | Passenger Frontal Airbag Canister Vent: Signal Cross Coupled | If the RCM detects a short between the passenger airbag canister vent circuit 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 circuit 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 driver side air curtain circuit 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 circuit 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 passenger side air curtain circuit and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component. |
| B140A:2B | Second Row Driver Side Airbag Deployment Control: Signal Cross Coupled | If the RCM detects a short between the second row driver side airbag circuit and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component. |
| B140B:2B | Second Row Passenger Side Airbag Deployment Control: Signal Cross Coupled | If the RCM detects a short between the second row passenger side airbag circuit and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component. |
| B1413:81 | Driver Frontal Restraints Sensor: Invalid Serial Data Received | If the RCM detects a short between the driver front impact severity sensor circuit and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component. |
| B1414:81 | Driver Side Restraints Sensor 1: Invalid Serial Data Received | If the RCM detects a short between the driver front door side impact sensor circuit and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component. |
| B1415:81 | Driver Side Restraints Sensor 2: Invalid Serial Data Received | If the RCM detects a short between the driver C-pillar side impact sensor circuit and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component. |
| B1417:81 | Passenger Frontal Restraints Sensor: Invalid Serial Data Received | If the RCM detects a short between the passenger front impact severity sensor circuit and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component. |
| B1418:81 | Passenger Side Restraints Sensor 1: Invalid Serial Data Received | If the RCM detects a short between the passenger front door side impact sensor circuit and the circuits of another SRS component, it sets this DTC and the DTC of the corresponding SRS component. |
| B1419:81 | Passenger Side Restraints Sensor 2: Invalid Serial Data Received | If the RCM detects a short between the passenger C-pillar side impact sensor circuit 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
WARNING:
Incorrect repair techniques or actions can cause an
accidental Supplemental Restraint System (SRS) deployment. Never
compromise or depart from these instructions. Failure to precisely
follow all instructions could result in serious personal injury from an
accidental deployment.
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| NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to 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: 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 or invalid data 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 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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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 or invalid data Diagnostic Trouble Codes (DTCs) retrieved on-demand during self-test?
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| A4 CHECK FOR AN INTERMITTENT FAULT | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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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 or invalid data 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) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Are any RCM Diagnostic Trouble Codes (DTCs) retrieved on-demand during self-test?
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Diagnosis and Testing - Pinpoint Test - DTC: AF, Vehicles With: Rear Seat Side Airbag