B0079 DTC – Fourth Row Left Seat Belt Pretensioner Circuit Fault

DTC B0079 indicates that the Supplemental Restraint System (SRS) has detected a fault in the fourth-row left seat belt pretensioner circuit. The pretensioner is responsible for tightening the seat belt during a collision to improve occupant protection.

Symptoms

• Airbag (SRS) warning light illuminated.
• B0079 stored in the SRS control module.
• Seat belt pretensioner disabled.
• Reduced occupant protection in a crash.

Possible Causes

• Faulty fourth-row left seat belt pretensioner.
• Loose or damaged electrical 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
           │
┌──────────▼─────────────┐
│ Fourth Row Left        │
│ Seat Belt              │
│ Pretensioner           │
└────────────────────────┘

Diagnostic Procedure

1. Scan the SRS system and record all stored DTCs.
2. Inspect the pretensioner connector for corrosion, loose terminals, or damage.
3. Inspect the wiring harness for open circuits, shorts, or physical damage.
4. Check circuit continuity using the factory wiring diagram.
5. Repair the fault, clear the DTC, and confirm that B0079 does not return.

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 cable and wait at least 10 minutes before servicing any SRS component. Never apply external voltage directly to a seat belt pretensioner.

Related DTCs

• B0077
• B0078
• B0080
• B0081