A disconnected or loose electrical connector at the pretensioner under the driver seat.; A broken or chafed wire in the pretensioner circuit, often due to seat movement or pinched harness.; Corrosion or damage to the pretensioner squib connector pins.; A faulty seatbelt pretensioner assembly with an open squib.; A defective restraint control module (airbag module) not supplying or reading the circuit correctly.; Aftermarket accessories or seat covers that interfere with the pretensioner wiring.

DTC codes / B00xx · Airbags, seats, doors, lights and comfort systems / B0072

B0072Driver Seatbelt Pretensioner Loop Open

Q: What does code B0072 mean?

Driver Seatbelt Pretensioner Loop Open. B0072 indicates that the restraint control module has detected an open circuit in the driver seatbelt pretensioner loop, meaning the electrical path through the pretensioner squib is broken. The module monitors a small test current through the loop and sets this code when the circuit resistance is higher than expected or the circuit is completely open.

B0072 indicates that the restraint control module has detected an open circuit in the driver seatbelt pretensioner loop, meaning the electrical path through the pretensioner squib is broken. The module monitors a small test current through the loop and sets this code when the circuit resistance is higher than expected or the circuit is completely open.

SystemBody

Code typeGeneric (all makes)

SeverityHigh

Fix difficultyProfessional

AreaAirbags, seats, doors, lights and comfort systems

Symptoms you may notice

The airbag or supplemental restraint system warning light is illuminated on the dashboard.
The seatbelt pretensioner may not deploy in a collision, increasing the risk of injury.
Often no symptoms besides the warning light, as the pretensioner is a one-time-use device.
Some vehicles may display a message such as 'Service Airbag' or 'Restraint System Failure'.
In rare cases, the seatbelt may feel loose or not retract properly if the pretensioner mechanism is physically damaged.

Common causes, most likely first

A disconnected or loose electrical connector at the pretensioner under the driver seat.
A broken or chafed wire in the pretensioner circuit, often due to seat movement or pinched harness.
Corrosion or damage to the pretensioner squib connector pins.
A faulty seatbelt pretensioner assembly with an open squib.
A defective restraint control module (airbag module) not supplying or reading the circuit correctly.
Aftermarket accessories or seat covers that interfere with the pretensioner wiring.

How to diagnose and fix it

Inspect the pretensioner connector under the driver seat for proper connection and corrosion; reseat if necessary.
Disconnect the battery and wait for the recommended time, then check the resistance of the pretensioner squib with a digital multimeter to confirm an open circuit.
Visually inspect the wiring harness from the module to the pretensioner for damage, chafing, or pinched wires, especially near seat tracks.
If the squib resistance is out of specification, replace the seatbelt pretensioner assembly as a unit.
If the wiring and pretensioner are good, test the circuit from the module side for continuity and check for short to ground or voltage.
Clear the code and verify the repair by cycling the ignition and confirming the light goes out and the code does not return.
If the code persists after all checks, diagnose or replace the restraint control module as the last step.

Before you replace the pretensioner

A common oversight is a loose connector under the seat that gets kicked or disturbed during cleaning or seat adjustment, so always check that first.
The pretensioner squib is a pyrotechnic device; never probe it with a powered test light or ohmmeter unless the battery is disconnected and you follow the manufacturer's safety procedure.
Seat-mounted side airbag wiring often shares the same harness path, so damage there can set multiple codes including B0072.
After a collision, even a minor one, the pretensioner may have deployed and the code will set; inspect for a deployed mechanism before diagnosing as a fault.
Some scan tools show this code as 'history' after a battery disconnect; clear it and verify it does not return before replacing parts.

Can I keep driving with B0072?

The vehicle is safe to drive in the sense that it will operate, but the driver seatbelt pretensioner will not function in a crash, so have it repaired promptly. Avoid any collision risk and do not ignore the warning light, as the restraint system may be compromised.

Tools that help

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