Airbag control unit with part number 150300-4650

What is the function of the airbag control unit 150300-4650?

The airbag control unit with part number 150300-4650 is the central control unit for the passive safety system in the Subaru Legacy, BM/BR generation (2009–2014). It continuously analyzes data from crash sensors and is responsible for precisely and rapidly deploying airbags and seatbelt pretensioners in the event of a collision.

As the “brain” of the restraint system, this component processes signals from acceleration and yaw rate sensors to assess the type and severity of a collision. Based on this analysis, the control unit determines which safety systems need to be activated to provide optimal protection for occupants. Without a fully functioning control unit, vehicle safety cannot be guaranteed.

The unit also communicates with other vehicle systems and stores relevant event and fault data in its internal memory. This data is crucial for post‑collision diagnostics and analysis.

Why does the control unit 150300-4650 fail?

The most common reason for requiring repair of the control unit 150300-4650 is stored crash data following an accident. Other causes include internal electronic faults that prevent communication with the diagnostic tool or make it impossible to clear error codes. A repair restores full functionality.

After a collision in which airbags or seatbelt pretensioners have deployed, the control unit stores so‑called “crash data.” For safety reasons, these data permanently lock the unit to prevent reuse without professional inspection. This condition is not a typical defect but requires specialized reprogramming to lift the lock.

In addition, internal electronic components may fail, leading to communication interruptions or persistently stored errors. Even if the external components of the airbag system—such as sensors or airbags—are functioning properly, the vehicle will still report a system fault due to the defective control unit.

Similar failure patterns are also observed in related variants, such as part numbers 150300-2150 and 150300-4670, which are likewise used in the Subaru Legacy V Estate (BR).

How do you recognize a defect in the 150300-4650?

A defect in the airbag control unit 150300-4650 primarily manifests as a constantly or intermittently illuminated airbag warning light on the instrument cluster. Additional symptoms include the inability to clear error codes or a complete lack of communication between the diagnostic tool and the control unit.

The clearest indication is the activated airbag warning lamp, signaling a fault in the restraint system and resulting in failure during the main vehicle inspection (TÜV). In this state, the system is not operational.

Another clear sign is when stored fault codes cannot be cleared, even though the underlying cause—such as a faulty sensor—has already been resolved. This suggests an internal fault within the control unit itself or the presence of stored crash data.

In some cases, a diagnostic tool may no longer establish any connection with the airbag control unit. The control unit fails to respond to queries, complicating troubleshooting and often pointing directly to a serious internal defect.

Before removing the control unit, it is recommended to have a thorough diagnosis performed at a specialized workshop. This ensures that the fault originates from the control unit itself and not from another vehicle component, such as wiring or a sensor.

In which models is the 150300-4650 installed?

The airbag control unit 150300-4650 is specified for the fifth-generation Subaru Legacy (BM/BR). At Airbag24, we offer professional repair services for this control unit, which was installed in models produced from 2009 to 2014, particularly in the station wagon variant.

At Airbag24, we repair part number 150300-4650 for the following specific model:

Subaru Legacy (BM/BR generation, model years 2009–2014)

Compatibility has been documented specifically for the station wagon/caravan body style equipped with the 2.457 cm³ engine and 123 kW output. Repair is also often possible for related control units, such as 150300-2150 and 150300-4670, which are used in the Subaru Legacy V Estate (BR).

How does the repair of the 150300-4650 work at Airbag24?

After sending the removed control unit to Airbag24, a professional analysis is conducted. The repair includes reprogramming to erase crash data and fixing internal faults. Upon successful restoration and final testing, you will receive the component back with 2 years’ statutory liability for defects.

The process ideally begins with a diagnosis at your workshop to rule out external sources of error. After the unit has been professionally removed, please send the defective control module to us securely packaged. Upon receipt, our technicians will subject it to a thorough inspection to determine the exact cause of the fault.

The actual repair focuses on rectifying the identified defects. This primarily involves resetting the stored crash data, thereby restoring the control module to full functionality. If necessary, faulty electronic components on the circuit board will also be replaced.

Subsequently, each repaired control module undergoes a functional test to ensure proper operation. The repair is a cost-effective and sustainable alternative to an expensive new purchase and typically does not require subsequent vehicle coding. We provide 2 years' statutory liability for defects on all repairs.