Airbag control unit with part number B8555-67U01

What is the function of the airbag control unit B8555-67U01?

The airbag control unit with part number B8555-67U01 is the central control module of the occupant restraint system (SRS) in the Infiniti Q45 of the G50 series. It processes data from crash sensors to deploy airbags and seatbelt pretensioners in the event of a collision. An alternative part number for this unit is 98820-AR012.

As an SRS control unit, the B8555-67U01 continuously monitors all components of the restraint system, from impact sensors to the airbag modules themselves. It is specifically designed for Infiniti Q45 G50 models manufactured between 1989 and 1996. Any system malfunction is recorded and stored in the fault memory, triggering the SRS warning light.

Why does the B8555-67U01 control unit fail?

The most common cause of failure for the B8555-67U01 control unit is the storage of crash data after a collision, which permanently locks the device. Other causes include electronic malfunctions due to faulty wiring, water damage, loose connectors, or failure of internal components on the circuit board.

After an airbag deployment, crash data is irrevocably stored in the control unit’s memory. This condition is intentionally programmed by the manufacturer to prevent reuse without professional inspection. Simple clearing of error codes via a diagnostic tool is no longer possible.

In addition to accident-related lockouts, age‑related hardware defects may also occur. These include broken wires, corrosion caused by moisture ingress, or cold solder joints at connector contacts, leading to intermittent or permanent failures. The alternative part number 98820-AR012 exhibits the same fault patterns.

How can you recognize a defect in the B8555-67U01?

A defective B8555-67U01 control unit primarily manifests as a constantly illuminated or flashing SRS warning light on the instrument panel. Often, communication with the control unit becomes impossible, resulting in diagnostic tools reporting errors such as B1000. Faults stored in the memory can no longer be cleared.

The most noticeable sign is the active airbag warning light, indicating to the driver that the entire occupant restraint system is disabled and airbags will not deploy in the event of a crash.

Another clear symptom is complete loss of communication. Workshops can no longer access the control unit with an OBD diagnostic tool to read or erase faults. Error codes like B1000 ("control unit communication error") may point to this condition.

Even when communication is possible, fault codes—especially after a crash—cannot be removed from memory. The system remains in fault mode until the control unit is repaired or replaced.

In which vehicles is the B8555-67U01 control unit installed?

The airbag control unit B8555-67U01, along with its alternative part number 98820-AR012, is specifically designed for the luxury Infiniti Q45 of the G50 series. This includes both the first generation and the later facelift model produced in the late 1980s and early 1990s.

At Airbag24, we specialize in repairing the B8555-67U01 control unit for the following specific vehicle models:

Infiniti Q45 G50 (model years 1989–1993)

Infiniti Q45 G50 Facelift (model years 1994–1996)

This component is also used in corresponding Nissan Infiniti Q45 models from the same era.

How does Airbag24 repair the B8555-67U01?

Professional repair at Airbag24 begins with an initial analysis of the removed control unit. Stored crash data is then erased, restoring the device to factory settings. Defective electronic components are replaced, followed by a comprehensive functional test and calibration.

Before removing the unit, we recommend a workshop diagnosis to rule out external issues with sensors or wiring. A diagnostic report should be included with the shipment.

Upon receipt at Airbag24, the B8555-67U01 control unit undergoes meticulous inspection. Our technicians analyze the fault memory and test the electronics down to the component level.

The core of the repair involves erasing crash data and restoring the hardware, which may include replacing capacitors or repairing printed circuit board damage.

Following successful repair, the unit undergoes a final quality check to ensure full functionality. You receive a tested component backed by 2 years' statutory liability for defects.