What it means
This code identifies a fault associated with the third-row right seatbelt pretensioner deployment control. The failure type byte specifies the detected fault.
How it works
The third-row right seat-belt pretensioner tightens that belt during a qualifying crash. The restraint control module monitors its deployment-control circuit, and B0078 records a fault associated with the circuit; the failure type byte provides the specific subfault.
Common causes
Most likely first.
- Pretensioner circuit wiring or connector fault
- Open or short in the deployment circuit
- Faulty pretensioner
- Restraints control module fault
Symptoms
- Airbag or SRS warning light
- Pretensioner may not operate as intended in a crash
How to diagnose it
- Read the restraint module's failure type byte and freeze-frame details to identify the condition reported for the third-row right pretensioner circuit.
- Inspect the third-row right belt and retractor for damage, obstruction, or abnormal movement.
- Check the accessible right pretensioner harness and connectors for looseness, corrosion, damaged pins, or chafing near folding or moving seat sections.
- Test the deployment circuit for an open or short using the manufacturer's restraint-system procedure and specification.
- If the circuit passes, check the third-row right pretensioner and then the restraint control module according to the manufacturer's diagnostic sequence.
Common fixes
- Reconnect or repair damaged third-row right pretensioner wiring using the approved procedure.
- Repair a confirmed open or short in the third-row right deployment circuit.
- Replace the third-row right pretensioner if testing confirms it is faulty.
- Repair or replace the restraint control module only after the circuit and pretensioner pass their checks.
Can I keep driving?
The vehicle may be driveable, but the third-row right pretensioner may not tighten its belt in a crash. Avoid using that seating position until the restraint fault is repaired.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.