Airbag control unit with part number K851M-EH001

What is the function of the airbag control unit K851M-EH001?

The airbag control unit K851M-EH001 is the central safety component in the Infiniti M45 Y50 (model years 2005–2010). Its primary role is to process signals from crash sensors, deploy airbags and seatbelt pretensioners in the event of a collision, and store relevant crash data in its internal memory.

As the brain of the passive safety system, this control unit is responsible for monitoring and managing all components of occupant protection. It continuously performs self-tests to ensure the system’s functionality. If a fault is detected, the airbag warning light in the cockpit illuminates immediately to alert the driver.

The data stored in the control unit is crucial for analyzing the circumstances of an accident. However, storing this so‑called crash data often results in permanent immobilization of the unit, necessitating repair or replacement.

Why does the K851M-EH001 control unit fail?

The most common cause of failure for the K851M-EH001 control unit is the storage of crash data after an airbag deployment. Other faults arise from internal electronic malfunctions, water damage, or age‑related wear of components. These issues block the unit’s functionality and require professional servicing.

Following an accident in which the airbags have deployed, the control unit irrevocably writes crash data into its internal memory. This lockout is a safety feature that prevents further operation of the module, even if the vehicle has otherwise been repaired. Erasing this data is a critical part of the repair process.

Electronic defects on the circuit board—such as failures in processors or memory chips—can also lead to complete system failure. Such internal faults are often indicated by diagnostic codes like B1065 or a generic message such as “internal airbag error” on the diagnostic tool. Even without an accident, these components may fail due to aging or voltage fluctuations.

How can you recognize a defect in the K851M-EH001?

A defect in the K851M-EH001 airbag control unit primarily manifests as a permanently illuminated or flashing airbag warning light (SRS light) in the instrument cluster. Communication between the control unit and a diagnostic tool is frequently lost, complicating troubleshooting.

The most obvious symptom is the persistently lit SRS warning light. It does not extinguish after starting the vehicle, indicating a serious, safety‑relevant fault within the system. In the event of another accident, the airbags might no longer deploy.

Another clear sign is complete loss of communication. When a specialized workshop attempts to read the fault memory, no response is received from the airbag control unit. This strongly suggests an internal fault within the control unit itself, rather than a problem with sensors or wiring.

After an accident, the illuminated warning light directly indicates stored crash data. The system is locked in this state and non‑functional. Immediate inspection at a qualified workshop is highly recommended, as occupant safety is no longer guaranteed.

In which vehicles is the K851M-EH001 control unit installed?

The airbag control unit with part number K851M-EH001 is specifically designed for Infiniti models. At Airbag24, we repair this control unit for the following vehicles, offering a cost‑effective and reliable alternative to expensive new parts.

Specifically, this control unit is used in:

Infiniti M45, Y50 series (model years 2005–2010)

Infiniti Premium M45

How does the repair of the K851M-EH001 work at Airbag24?

Repair at Airbag24 follows a standardized process to ensure full restoration of functionality. After removal and shipment, the control unit undergoes an initial inspection to precisely identify the source of the fault. Next, crash data is erased, defective components are replaced, and a final functional test is performed.

Before removing the control unit, it is recommended to have the fault memory read at a specialized workshop to confirm that the issue truly lies within the control unit. Following proper disassembly, carefully package the unit and include the completed repair form.

Upon receipt at Airbag24, our technicians analyze the device. Depending on the nature of the fault, stored crash data is professionally reset, or defective electronic components on the circuit board are replaced. Each repair concludes with a thorough final inspection to guarantee full compliance with manufacturer specifications. We provide a 12‑month warranty on all repairs.

What shipping options are available at Airbag24?

Airbag24 offers flexible and secure shipping options. You can either send your defective control unit yourself or take advantage of our free UPS pickup service. For returning the repaired unit, various UPS services are also available, including express and cash-on-delivery options.

For the outbound shipment, you can either mail the package to us yourself or arrange a convenient, free UPS pickup at your preferred location. Alternatively, you can drop off the item in person at one of our locations.

For returning the repaired control unit, we offer the following options:

Free UPS standard shipping (1–3 business days)

UPS express shipping (1–2 business days)

UPS standard shipping with cash on delivery (1–3 business days)

UPS express shipping with cash on delivery (1–2 business days)

In-person pickup at our premises