A damaged or disconnected electrical connector at the driver's seat belt pretensioner B, often caused by seat movement or debris.; A broken or chafed wire in the pretensioner harness, typically where it flexes near the seat track or sill.; High resistance or an open circuit inside the pretensioner squib itself, which requires replacement of the pretensioner assembly.; Corrosion or water intrusion at the connector or in the harness, especially on vehicles with sunroof drains or floor leaks.; A faulty restraint control module that is unable to read the deployment circuit correctly, though this is less common.; Aftermarket seat covers, seat heaters, or accessories that interfere with the pretensioner wiring or connector.; A short to ground or short to voltage in the deployment circuit caused by pinched wiring during seat removal or repair.

DTC codes / B00xx · Airbags, seats, doors, lights and comfort systems / B0079

B0079Driver Seat Belt Pretensioner B Deployment Control

Q: What does code B0079 mean?

Driver Seat Belt Pretensioner B Deployment Control. B0079 indicates that the restraint control module has detected a fault in the deployment circuit for the driver's seat belt pretensioner B, which is the second pretensioner on the driver's side in vehicles with dual-stage or multi-stage belts. The module monitors the circuit's resistance and continuity and sets this code when the signal falls outside the expected range, which can prevent that pretensioner from firing in a collision.

B0079 indicates that the restraint control module has detected a fault in the deployment circuit for the driver's seat belt pretensioner B, which is the second pretensioner on the driver's side in vehicles with dual-stage or multi-stage belts. The module monitors the circuit's resistance and continuity and sets this code when the signal falls outside the expected range, which can prevent that pretensioner from firing in a collision.

SystemBody

Code typeGeneric (all makes)

SeverityHigh

Fix difficultyProfessional

AreaAirbags, seats, doors, lights and comfort systems

Symptoms you may notice

The supplemental restraint system (SRS) warning light stays illuminated on the instrument cluster.
A chime or message may appear on the driver information center advising service of the restraint system.
The seat belt may not lock or tension as designed during a collision, reducing occupant protection.
In some vehicles, the airbag system may be partially disabled or placed in a default deployment strategy.
Often no symptoms besides the warning light, with the belt feeling and operating normally in everyday use.

Common causes, most likely first

A damaged or disconnected electrical connector at the driver's seat belt pretensioner B, often caused by seat movement or debris.
A broken or chafed wire in the pretensioner harness, typically where it flexes near the seat track or sill.
High resistance or an open circuit inside the pretensioner squib itself, which requires replacement of the pretensioner assembly.
Corrosion or water intrusion at the connector or in the harness, especially on vehicles with sunroof drains or floor leaks.
A faulty restraint control module that is unable to read the deployment circuit correctly, though this is less common.
Aftermarket seat covers, seat heaters, or accessories that interfere with the pretensioner wiring or connector.
A short to ground or short to voltage in the deployment circuit caused by pinched wiring during seat removal or repair.

How to diagnose and fix it

Inspect the driver's seat belt pretensioner B connector for looseness, corrosion, or damaged pins, and reseat or clean it as needed.
Check the pretensioner harness for chafing, pinches, or breaks along the seat track and under the seat, repairing any damaged wire.
Measure the resistance of the pretensioner squib with a proper meter and compare it to the manufacturer's specification to confirm an internal fault.
Clear the code and recheck after each repair to verify whether the fault returns before moving to the next step.
If the squib resistance is out of range, replace the driver's seat belt pretensioner B assembly following the manufacturer's procedure.
If the circuit and pretensioner test good, perform a restraint control module diagnostic self-test and replace the module only if it fails.
After any repair, verify the SRS warning light extinguishes and no codes return during a complete drive cycle.

What technicians check before replacing the pretensioner

A loose connector under the driver's seat is the most common cause of B0079, and simply reseating it often clears the code permanently.
The code can be set by a momentary open circuit when the seat is moved fully forward or backward, so always test the circuit with the seat in several positions.
Never use a standard ohmmeter on a live airbag or pretensioner circuit; always disconnect the battery and wait the specified time before probing the squib.
B0079 does not always mean the pretensioner is defective; a poor ground or a low battery voltage during cranking can cause a false set.
Aftermarket seat covers or seat heaters that pinch the pretensioner harness are a frequently missed cause, especially on vehicles that have had interior work.

Can I keep driving with B0079?

The vehicle remains drivable, but the driver's seat belt pretensioner B may not deploy in a crash, so avoid collisions and have the fault repaired promptly. Do not ignore the warning light, because the restraint system may be compromised for that seating position.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.