Poor connection or damaged connector at the passenger seat belt pretensioner or the under-seat or B-pillar connector; Damaged wiring in the pretensioner circuit, such as chafing, an open circuit or a short to earth or supply, often from seat movement or previous work; Faulty pretensioner unit (squib resistance out of range); Corrosion or moisture in connectors or the seat belt buckle and retractor area, for example after a leak or spill; Previous crash or repair left a damaged, deployed or incorrectly fitted pretensioner or connector; Fault inside the restraint control unit's deployment driver circuit.

B0072

Passenger Seat Belt Pretensioner A Deployment Control.

Generic
Body
Generic code
High severity

How this code is built

B: SystemBody
0: Defined bySAE, the same on every car
0: AreaBody area 0
72: FaultThe specific fault in that area

What it means

B0072 is the generic code for a fault in the deployment control of the passenger seat belt pretensioner (stage A). The restraint control unit tests the pretensioner's firing circuit (the squib and its wiring) on every start-up and while driving. It set the code because it saw a resistance, voltage or continuity reading outside the expected range, or a fault in its own driver circuit. The exact wording and how the circuit is tested vary by manufacturer and model.

Symptoms

Airbag or SRS warning light on the dashboard
Passenger seat belt pretensioner may not fire in a collision
Seat belt warning light or message may show alongside the airbag light
Passenger airbag may also be disabled or flagged as faulty
Intermittent warning light that comes and goes with seat movement or bumps

Possible causes

Poor connection or damaged connector at the passenger seat belt pretensioner or the under-seat or B-pillar connectorlikely
Damaged wiring in the pretensioner circuit, such as chafing, an open circuit or a short to earth or supply, often from seat movement or previous worklikely
Faulty pretensioner unit (squib resistance out of range)possible
Corrosion or moisture in connectors or the seat belt buckle and retractor area, for example after a leak or spillpossible
Previous crash or repair left a damaged, deployed or incorrectly fitted pretensioner or connectorpossible
Fault inside the restraint control unit's deployment driver circuitrare

How to diagnose

Read all stored codes and freeze frame data, noting whether B0072 is current, stored or intermittent and whether other SRS codes are present
Ask about previous accident damage, seat or trim removal, water ingress or recent SRS work
Visually inspect the passenger belt retractor, its connector and the harness routing for damage, pinching, corrosion or loose or unlatched connectors
Before disconnecting any SRS connector, switch off the ignition, disconnect the battery and wait for the time stated in the manufacturer's procedure so the system is safely discharged
Check the connector terminals for bent, pushed-back or corroded pins and for the correct fitting of any shorting clips
Test the wiring for continuity and for shorts to earth or supply using the manufacturer's procedure, never probing the pretensioner directly with a test meter or energising it
Check the pretensioner resistance only with the method and equipment the manufacturer specifies, because incorrect testing can fire it
Clear the code, then test by moving the seat and flexing the harness to see if the fault returns

How to fix

Repair or replace damaged wiring or connectors in the pretensioner circuit, following the manufacturer's repair rules
Clean or replace corroded connectors and cure any water leak that caused the corrosion
Replace the faulty or damaged seat belt pretensioner or retractor assembly, using the correct part for the model
Refit or correctly seat connectors and any locking or shorting clips
Replace the restraint control unit only once the wiring and pretensioner are proven good, then carry out any required setup or coding
Clear the code and confirm the SRS warning light goes out and does not return after a test drive

Can I keep driving?

High severity

The car can usually be driven, but the passenger belt pretensioner may not work in a crash, so protection is reduced. Limit use, avoid carrying a front passenger where possible, and get the fault repaired promptly.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.