B0073 – Second Row Right Seat Belt Pretensioner Deployment Loop Circuit Fault

DTC B0073 indicates that the Supplemental Restraint System (SRS) has detected a fault in the second-row right seat belt pretensioner deployment loop circuit. The fault may be caused by an open circuit, short to ground, short to battery voltage, excessive resistance, or a failed pretensioner assembly.

Important: The exact definition of B0073 depends on the vehicle manufacturer. Always consult the factory service information before replacing SRS components.

Symptoms

• Airbag (SRS) warning light illuminated.
• Rear right seat belt pretensioner disabled.
• B0073 stored in the SRS control module.
• Additional airbag system DTCs may also be present.

Possible Causes

• Faulty second-row right seat belt pretensioner.
• Open circuit in the deployment loop.
• Short to ground or battery voltage.
• Loose or corroded connector.
• Damaged wiring harness.
• Faulty SRS control module.

Typical Signal Flow Diagram

        +12V Battery
             │
        Ignition ON
             │
      ┌──────────────┐
      │  SRS Module  │
      └──────┬───────┘
             │
     Deployment Loop
             │
 ┌──────────────────────────────┐
 │ Rear Right Seat Belt         │
 │ Pretensioner Assembly        │
 └─────────────┬────────────────┘
               │
         Return Circuit
               │
          SRS Module

Note: Wire colors, connector pin assignments, and resistance specifications vary depending on vehicle make and model.

Diagnostic Procedure

1. Read all stored SRS DTCs using a professional scan tool.
2. Inspect the rear right seat belt pretensioner connector.
3. Check the wiring harness for damage, pinched wires, or corrosion.
4. Verify connector terminal tension.
5. Perform continuity and resistance tests according to the factory repair manual.
6. Repair wiring or replace defective components.
7. Clear the DTC and verify the repair.

Recommended Repairs

• Repair damaged wiring harness.
• Replace corroded or loose connectors.
• Replace the rear right seat belt pretensioner if faulty.
• Repair open or short circuits.
• Replace or reprogram the SRS module only after confirming all other components are operating correctly.

Safety Warning

Disconnect the negative battery cable and wait at least 10–15 minutes before servicing any SRS component. Never apply voltage directly to a seat belt pretensioner or airbag inflator.

Related DTC Codes

• B0070
• B0071
• B0072
• B0074
• B0080

Frequently Asked Questions (FAQ)

What does B0073 mean?

B0073 indicates a fault in the second-row right seat belt pretensioner deployment loop circuit.

Can I continue driving with B0073?

The vehicle may still be drivable, but the rear right seat belt pretensioner may not activate correctly during an accident.

What usually causes B0073?

The most common causes include damaged wiring, loose connectors, corrosion, or a faulty rear right seat belt pretensioner.

Will clearing the DTC fix the problem?

No. If the electrical fault has not been repaired, the code will return after the SRS self-test.