B0002 MERCURY Possible Causes

• Faulty driver airbag
• Driver airbag harness is open or shorted
• Poor electrical connection in driver airbag circuit

How to Fix B0002 MERCURY Code?

Start by checking the “possible causes” listed above. Visually inspect the wiring harness and related connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

When is the Code Detected?

If the restraint control module detects a short circuit between the driver airbag stage 2 circuits and the circuits of another SRS component, it sets this DTC and the corresponding SRS component’s detected fault code (DTC).

Possible Symptoms

Airbag warning light illuminated

B0002 MERCURY Meaning

The Restraint Control Module (RCM) monitors all deployable device and sensor circuits for a coupled signal (short) between circuits. If the RCM detects a short circuit between the circuits of one device and another device, it will store a DTC for each of the signal cross-coupling faults in memory. The RCM sends a message to the instrument panel (IPC) to illuminate the airbag warning light. When a normal loop fault is present (a loop is either shorted to battery/ground, open circuit, or low resistance), then the signal cross-coupling diagnostic will not be active. Once the normal loop fault is repaired, the signal cross-coupling diagnostic resumes…

B0002 NISSAN Possible Causes

• Faulty driver airbag module
• Driver airbag module harness is open or shorted
• Poor electrical connection in driver airbag module circuit
• Faulty spiral cable
• Faulty airbag diagnostic sensor

How to Fix B0002 NISSAN Code?

Start by checking the “possible causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Airbag warning light illuminated

B0002 NISSAN Meaning

The driver airbag module is dual-stage and is wired to the airbag diagnostic sensor unit through the spiral cable. The airbag diagnostic sensor unit will monitor for opens and shorts in the detected lines to the driver airbag module, including the spiral cable. The airbag sensor unit (airbag control module) monitors the driver airbag module. The airbag sensor unit sets the OBDII code when the driver airbag module does not meet factory specifications.

Meaning of Code B0003

This OBD-II code indicates a configuration or communication issue with the sophisticated airbag sensor command module (SAS). The SAS is responsible for monitoring collision sensors and deploying airbags in the event of an accident. Incorrect configuration or an electrical fault prevents the system from functioning properly, compromising occupant safety.

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Severity

High Level:

• Compromised Safety: Airbags may not deploy in an accident.

• Airbag warning light illuminated continuously.

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Common Symptoms

• Airbag light illuminated on the dashboard.

• Airbag system error message displayed (depending on model).

• Complete airbag system failure (in severe cases).

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Possible Causes

1. Software configuration error in the SAS module (after reset or service).

2. Faulty SAS module (internal circuit or microprocessor failure).

3. Electrical issues:

   • Open circuit or short circuit in the wiring harness.

   • Damaged, corroded, or improperly connected connectors.

4. Faulty power supply or ground to the SAS module.

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Diagnostic Procedure

Step 1: Visual Inspection

1. Disconnect the battery (wait 15 minutes to deactivate the airbag system).

2. Locate the SAS module (usually under the driver’s seat, in the center console, or near the steering wheel).

3. Inspect the wiring harness and connectors:

   • Look for cut, chafed wires, or signs of corrosion.

   • Check the condition of the pins (bent, broken, corroded).

Step 2: Electrical Check

1. Measure the supply voltage:

   • Use a multimeter to check for 12V at the SAS power terminals.

2. Test circuit continuity:

   • Check for no short circuit or open circuit between the SAS and the airbag control unit.

Step 3: Software Diagnosis

• Use a specialized diagnostic tool (e.g., manufacturer scanner) to:

  • Read specific error codes from the airbag system.

  • Reconfigure the SAS module if necessary.

  • Update the SAS software (if TSBs recommend it).

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Recommended Solutions

• Reconfigure the SAS module using a certified diagnostic tool.

• Replace the SAS module if faulty (often requires post-installation programming).

• Repair the wiring harness: Replace damaged sections and clean connectors with contact spray.

• Restore power/ground if a fault is detected.

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Precautions

• Handle with care: The airbag system contains pyrotechnic explosives.

• Wear protective equipment (goggles, gloves) during work.

• Consult the vehicle-specific repair manual to avoid accidental deployment.

B0003 MAZDA Possible Causes

• Configuration error of the sophisticated airbag sensor module (SAS)
• Faulty sophisticated airbag sensor module (SAS)
• Open or short circuit in the sophisticated airbag sensor module (SAS) wiring harness
• Poor electrical connection in the sophisticated airbag sensor module (SAS) circuit

How to Fix B0003 MAZDA Code?

Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Airbag warning light illuminated

B0003 MAZDA Meaning

The sophisticated airbag sensor module (SAS) sets the OBDII code when the configuration has not been set.

B0004 Possible Causes

• Faulty driver knee airbag
• Driver knee airbag harness is open or short-circuited
• Poor electrical connection in driver knee airbag circuit

How is B0004 Code Repaired?

Start by checking the “Possible Causes” listed above. Visually inspect the corresponding wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

When is the Code Detected?

If the Restraints Control Module (RCM) detects a short circuit between the driver knee airbag circuits and the circuits of another SRS component, it sets this Diagnostic Trouble Code (DTC) and the corresponding SRS component DTC.

Possible Symptoms

Airbag warning light illuminated

B0004 Meaning

The Restraints Control Module (RCM) monitors all deployable device and sensor circuits for a coupled signal (short) between circuits. If the RCM detects a short circuit between the circuits of one device and another device, it will store a DTC for each of the signal cross-coupling faults in memory. The RCM sends a message to the instrument panel cluster (IPC) to illuminate the airbag warning indicator. When a normal loop fault is present (a loop is either shorted to battery/ground, or open circuit or low resistance), then the signal cross-coupling diagnostic will not be active. Once the normal loop fault is repaired, the signal cross-coupling diagnostic resumes.

B0004 FORD Possible Causes

• Faulty driver knee airbag
• Driver knee airbag harness is open or short-circuited
• Poor electrical connection in the driver knee airbag circuit

How to Fix B0004 FORD Code?

Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

When is the Code Detected?

If the Restraints Control Module (RCM) detects a short circuit between the driver knee airbag circuits and the circuits of another SRS component, it sets this Diagnostic Trouble Code (DTC) and the corresponding SRS component DTC.

Possible Symptoms

Airbag warning light illuminated

B0004 FORD Meaning

The Restraints Control Module (RCM) monitors all deployable device and sensor circuits for a coupled signal (short) between circuits. If the RCM detects a short circuit between the circuits of one device and another device, it will store a DTC for each of the signal cross-coupling faults in memory. The RCM sends a message to the instrument panel cluster (IPC) to illuminate the airbag warning indicator. When a normal loop fault is present (a loop is either shorted to battery/ground, open circuit, or low resistance), then the signal cross-coupling diagnostic will not be active. Once the normal loop fault is repaired, the signal cross-coupling diagnostic resumes.

B0004 LINCOLN Possible Causes

• Faulty driver knee airbag
• Driver knee airbag harness is open or shorted
• Poor electrical connection in driver knee airbag circuit

How to Fix B0004 LINCOLN Code?

Start by checking the “possible causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

When is the Code Detected?

If the Restraints Control Module (RCM) detects a short circuit between the driver knee airbag circuits and another SRS component’s circuits, it sets this Diagnostic Trouble Code (DTC) and the corresponding SRS component DTC.

Possible Symptoms

Airbag warning light illuminated

B0004 LINCOLN Meaning

The Restraints Control Module (RCM) monitors all deployable device and sensor circuits for a coupled signal (short) between circuits. If the RCM detects a short circuit between one device’s circuits and another device’s circuits, it will store a DTC for each of the signal cross-coupling faults in memory. The RCM sends a message to the instrument panel cluster (IPC) to illuminate the airbag warning light. When a normal loop fault is present (a loop is either shorted to battery/ground, open circuit, or low resistance), then the signal cross-coupling diagnostic will not be active. Once the normal loop fault is repaired, the signal cross-coupling diagnostic resumes.

B0004 MERCURY Possible Causes

• Faulty driver knee airbag
• Driver knee airbag harness is open or short-circuited
• Poor electrical connection in the driver knee airbag circuit

How to Fix B0004 MERCURY Code?

Start by checking the “possible causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

When is the Code Detected?

If the Restraint Control Module (RCM) detects a short circuit between the driver knee airbag circuits and the circuits of another SRS component, it sets this Diagnostic Trouble Code (DTC) and the corresponding SRS component DTC.

Possible Symptoms

Airbag warning light illuminated

B0004 MERCURY Meaning

The Restraint Control Module (RCM) monitors all deployable device and sensor circuits for a coupled signal (short) between circuits. If the RCM detects a short circuit between the circuits of one device and another device, it will store a DTC for each of the signal cross-coupling faults in memory. The RCM sends a message to the instrument panel cluster (IPC) to illuminate the airbag warning light. When a normal loop fault is present (a loop is either shorted to battery/ground, open, or has low resistance), then the signal cross-coupling diagnostic will not be active. Once the normal loop fault is repaired, the signal cross-coupling diagnostic resumes.

B0005 Possible Causes

• Faulty collapsible steering column
• Collapsible steering column wiring harness is open or shorted
• Poor electrical connection in collapsible steering column circuit
• Faulty Restraint Control Module (RCM)

How to Fix B0005 Code?

Start by checking the “Possible Causes” listed above. Visually inspect the wiring harness and related connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Technical Notes

What Does It Mean?

B0005: 12 Collapsible Steering Column Deployment Control: Short to Battery
B0005: 13 Collapsible Steering Column Deployment Control: Circuit Open
B0005: 1A Collapsible Steering Column Deployment Control: Circuit Resistance Below Threshold
B0005: 2B Collapsible Steering Column Deployment Control: Cross Coupled Signal
B0005: 4A Collapsible Steering Column Deployment Control: Incorrect Component Installed

Possible Symptoms

Airbag warning light illuminated

B0005 Meaning

The Restraint Control Module (RCM) monitors the deployment loop resistance to determine if a fault exists. The value displayed in Parameter Identification (PID) is the deployment loop resistance measured by the RCM. If the displayed value is below or above the desired range, the RCM may set a Diagnostic Trouble Code (DTC). As the deployment loop resistance moves further away from the desired range, the likelihood of a DTC increases. Small resistance variations may occur due to the effect of road vibrations on terminal fit. Crimps and terminals can be affected by wiring harness stress and movement and may cause increased resistance due to wire tension. These variables can result in an intermittent fault. For this reason, the test requires the Parameter Identification (PID) value to be within the desired range before the fault is considered repaired, whether the module reports a DTC on demand at the time of diagnosis. Following this direction helps ensure that minor resistance changes do not create a recurring problem. This test uses the process of elimination to diagnose each part of the deployment loop circuit, including wiring, connections, collapsible steering column, and RCM.

B0005 FORD Possible Causes

• Faulty deployable steering column
• Deployable steering column wiring harness is open or shorted
• Poor electrical connection in the deployable steering column circuit
• Faulty Restraint Control Module (RCM)

How to Fix B0005 FORD Code?

Start by checking the “Possible Causes” listed above. Visually inspect the wiring harness and corresponding connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Technical Notes

What Does It Mean?

B0005: 12 Deployable Steering Column Deployment Control: Short to Battery
B0005: 13 Deployable Steering Column Deployment Control: Circuit Open
B0005: 1A Deployable Steering Column Deployment Control: Circuit Resistance Below Threshold
B0005: 2B Deployable Steering Column Deployment Control: Cross Coupled Signal
B0005: 4A Deployable Steering Column Deployment Control: Incorrect Component Installed

Possible Symptoms

Airbag warning light illuminated

B0005 FORD Meaning

The Restraint Control Module (RCM) monitors the deployment loop resistance to determine if a fault exists. The value displayed in the Parameter Identification (PID) is the deployment loop resistance measured by the RCM. If the displayed value is below or above the desired range, the RCM may set a Diagnostic Trouble Code (DTC). As the deployment loop resistance moves further away from the desired range, the likelihood of a DTC increases. Small resistance variations may occur due to the effect of road vibrations on terminal fit. Crimps and terminals can be affected by wiring harness stress and movement and may cause increased resistance due to wire tension. These variables can result in an intermittent fault. For this reason, the test requires the Parameter Identification (PID) value to be within the desired range before the fault is considered repaired, whether the module reports a DTC on demand at the time of diagnosis. Following this direction helps ensure that minor resistance changes do not create a recurring problem. This test uses the process of elimination to diagnose each part of the deployment loop circuit, including wiring, connections, the deployable steering column, and the RCM.