Airbag control unit with part number A1179005800

What is the function of the airbag control unit A1179005800?

The airbag control unit A1179005800 is the central control module for the entire occupant protection system in Mercedes-Benz CLA models of the C117, X117, and C118 series. As an original OEM part, it processes data from crash sensors and determines whether and which airbags or seatbelt pretensioners need to be deployed in the event of a collision.

This unit is critical to the vehicle’s passive safety. It continuously monitors all connected components of the restraint system, including various airbags (driver, passenger, side, head), seatbelt pretensioners, and seat occupancy detection. Without a properly functioning control unit, the protective functions of these systems cannot be guaranteed.

In normal operation, the control unit communicates with other vehicle systems, such as ABS or ESP, to obtain a comprehensive picture of the driving situation. In case of a malfunction, this communication is disrupted, leading to deactivation of the entire safety system.

Why does the control unit A1179005800 fail?

The most common causes of failure for the control unit A1179005800 are stored crash data following an accident or the failure of internal electronic components. Once crash information is stored, the unit becomes locked and cannot be reused, while defective components such as capacitors or microcontrollers can completely disable its functionality.

After an accident—or even minor collisions—the unit irrevocably stores so‑called crash data. This is a manufacturer‑imposed safety measure that locks the device to prevent reuse without professional diagnostics. Such data cannot be erased using standard diagnostic tools.

Additionally, individual electronic components on the circuit board may also fail. These typically include microcontrollers, resistors, or capacitors that deteriorate due to aging or thermal stress. Such hardware defects result in internal malfunctions and system deactivation.

In some cases, extended variants like part number A1179009200 are used for the vehicle, which may exhibit similar fault patterns. Therefore, precise diagnosis is essential to identify the exact cause of the issue.

How do you recognize a defect in the A1179005800?

The clearest symptom of a defect in the airbag control unit A1179005800 is the permanently illuminated airbag warning light on the Mercedes-Benz CLA’s instrument cluster. If this warning lamp stays lit, the entire restraint system is usually deactivated and offers no protection in the event of a crash.

The airbag warning light does not turn off after starting the vehicle, indicating a serious system error. This is a clear sign that the control unit has detected an internal fault or is locked due to stored crash data.

In the workshop, the defect can often be confirmed by the absence or malfunction of communication with the diagnostic tool. The control unit no longer responds to queries, or specific error codes are recorded, pointing to an internal device failure.

In which vehicles is the control unit A1179005800 installed?

This OEM airbag control unit is specifically designed for various models within the Mercedes-Benz CLA lineup. It is used across multiple model years in both the sedan (C117 and C118) and the Shooting Brake (X117). At Airbag24, we repair the A1179005800 control unit for the following vehicles:

Mercedes-Benz: CLA C117 Sedan (2013–2019), CLA X117 Shooting Brake (2015–2019), CLA C118 Sedan (from 2019)

Is repairing the A1179005800 worthwhile?

Yes, repair is an economically and technically sensible solution. A new part often costs between 500 and 800 euros, whereas repair offers significant savings. The original unit is refurbished, ensuring compatibility and eliminating the need for time-consuming reprogramming of the vehicle.

Through targeted component-level restoration, only defective parts are replaced, and crash data is professionally erased. The control unit then regains full functionality. This approach is not only more cost-effective but also more sustainable than replacing it with an expensive new unit.

Furthermore, you receive a 12-month warranty on the completed repair. You will get your original, vehicle‑specific control unit back in perfect working condition.

How is the A1179005800 professionally repaired?

Professional repair involves purely electronic intervention to address the root cause of the defect. After sending the removed unit to Airbag24, a thorough diagnosis is performed. Defective components such as resistors or microcontrollers are replaced, and stored crash data is erased. Final tests ensure full functionality.

The process at Airbag24 is standardized and designed for the highest quality. First, the control unit is removed from the vehicle and securely packaged before being shipped to us. Our technicians then perform an incoming inspection to verify the reported fault.

Next, repairs are carried out at the component level. Defective parts are precisely desoldered and replaced with new, high-quality components. If crash data is stored, it is completely and irreversibly erased from the control unit’s memory using specialized programming tools.

Following repair, the control unit undergoes a comprehensive functional test on a test bench that simulates real‑world driving conditions. Only after passing all tests is the unit approved for return shipment. We provide a 12‑month warranty on every repair.

What shipping options does Airbag24 offer?

Airbag24 offers flexible and secure shipping options. You can either send your defective control unit yourself free of charge or arrange a convenient UPS pickup from a location of your choice. For return shipping, you have access to free UPS standard delivery, faster express options, and cash-on-delivery payment.

For outbound shipping, you have two choices: you can mail the package to us yourself or use UPS’s pickup service, which collects the package directly from your home or workshop.

After the repair is completed, we ship the control unit back to you by default via free UPS standard delivery (1–3 business days). If you need it sooner, you can opt for UPS express delivery (1–2 business days). Both options are also available with cash-on-delivery. Alternatively, you can pick up the repaired unit in person at our facility.