B0077 DTC – Third Row Right Seat Belt Pretensioner Circuit Fault

DTC B0077 indicates that the Supplemental Restraint System (SRS) has detected a fault in the third-row right seat belt pretensioner circuit. The pretensioner is activated during a collision to tighten the seat belt and improve occupant protection.

Symptoms

• Airbag (SRS) warning lamp ON.
• B0077 stored in the SRS module.
• Seat belt pretensioner disabled.
• Possible "Service Airbag" message.

Possible Causes

• Defective third-row right seat belt pretensioner.
• Loose or damaged connector.
• Open circuit in the wiring harness.
• Short to ground or battery voltage.
• Corroded connector terminals.
• Faulty SRS control module (rare).

Typical Wiring Diagram

┌───────────────────────┐
│      SRS MODULE       │
└──────────┬────────────┘
           │
           │ Control Signal
           │
┌──────────▼────────────┐
│       CONNECTOR       │
└──────────┬────────────┘
           │
           │ Wiring Harness
           │
┌──────────▼────────────┐
│ Seat Belt             │
│ Pretensioner          │
│ (3rd Row - Right)     │
└───────────────────────┘

Diagnostic Procedure

1. Read all SRS trouble codes with a professional scan tool.
2. Inspect the pretensioner connector for loose pins or corrosion.
3. Check the wiring harness for damage or pinched wires.
4. Verify circuit continuity using the factory wiring diagram.
5. Repair or replace the faulty component, clear the DTC, and perform a final system check.

Live Data Inspection

• Pretensioner Status: Normal
• Deployment Circuit: Active
• Open Circuit: No
• Short to Ground: No
• Short to Battery: No
• Circuit Resistance: Within manufacturer specification

Safety Notice

Disconnect the negative battery terminal and wait at least 10 minutes before working on any SRS component. Never apply battery voltage directly to a seat belt pretensioner.

Related DTCs

• B0075
• B0076
• B0078
• B0079