Airbag control unit with part number A2049013702

What is the function of the airbag control unit A2049013702?

The airbag control unit with part number A2049013702 is the central control module for the passive safety system (SRS) in the Mercedes-Benz GLK-Class (X204). It processes data from crash sensors and determines whether to deploy airbags and seatbelt pretensioners, thereby protecting occupants during a collision.

As the “brain” of the restraint system, this control unit is responsible for monitoring all safety‑related components. It continuously analyzes signals from acceleration sensors and seat occupancy mats.

In the event of a collision whose severity warrants deployment, the unit sends ignition commands to the appropriate airbags and seatbelt pretensioners within milliseconds. Manufacturers such as Bosch or TRW are often responsible for producing this safety‑critical electronics.

The control unit is designed specifically for the GLK model of the X204 series, tailored to its vehicle identification number (VIN) and equipment configuration. Compatible variants like A2049012904 and A2049012704 share this basic architecture. Associated manufacturer part numbers may include 5WK44526 or 5WK44741.

Why does the control unit A2049013702 fail?

The most common cause of failure for the A2049013702 control unit is stored crash data following an accident, which locks the device. Other reasons include internal hardware defects leading to complete communication failure, or age‑related issues with electronic components.

After a crash, the control unit permanently stores non‑erasable “crash data.” This is a manufacturer‑imposed safety measure that locks the unit, preventing reuse without professional repair. In some cases, the stored vehicle identification number (VIN) is also lost.

Another frequent issue is total loss of communication. Workshops can no longer access the control unit using diagnostic tools such as Star Diagnosis. This indicates a serious internal hardware fault, possibly affecting the processor or communication modules.

Occasionally, other electronic problems arise—such as thermal failures where the unit malfunctions when heated, or faults causing sporadic error messages and the persistent illumination of the airbag warning light. These issues also affect related part numbers A2049012904 and A2049012704.

How do you recognize a defect in the A2049013702 control unit?

A defective A2049013702 control unit primarily manifests as the airbag warning light (SRS light) remaining constantly illuminated on the instrument cluster. Communication with diagnostic equipment is often impossible, and specific error messages may appear on the display.

The most obvious sign is the active airbag indicator light, which fails to extinguish after starting the engine, signaling a critical fault in the restraint system. A vehicle with this issue will not pass the main inspection (TÜV).

In the workshop, the defect often becomes apparent when diagnostic tools such as Bosch testers, Gutmann devices, or the manufacturer‑specific Star Diagnosis cannot establish a connection to the control unit. Reading out error codes is therefore impossible.

The onboard computer may display error messages like “Airbags defective,” or even seemingly unrelated warnings such as a problem with the “fuel shut-off valve.” The failure of the clock on the instrument panel has also been observed in association with this defect.

This type of malfunction poses a significant safety risk, as the entire airbag system becomes inoperative in the event of a crash. Before repairing the control unit, external sources of errors—such as faulty sensors or seat occupancy mats—should be ruled out by a qualified workshop.

In which vehicles is the A2049013702 control unit installed?

The A2049013702 airbag control unit is specifically designed for the Mercedes-Benz GLK-Class model of the X204 series, produced from 2008 to 2015. It is used across various engine configurations, including the GLK 350 4MATIC.

At Airbag24, we repair this control unit as well as compatible variants A2049012904 and A2049012704 for the following model:

Mercedes-Benz: GLK‑class SUV (X204 series), manufactured between 2008 and 2015.

Assignment depends heavily on the vehicle identification number (VIN) and the vehicle’s specific equipment configuration. Therefore, it is crucial to verify the exact part number before submitting a repair request.

What are the advantages of repair over replacing with a new unit?

Repairing the A2049013702 control unit offers substantial cost savings—often exceeding 70% compared to purchasing a new unit. Additionally, there is no need for time‑consuming reprogramming, as the vehicle‑specific configuration remains fully intact.

A new airbag control unit from the manufacturer often costs over 1,000 euros. Repair is a far more economical alternative, without compromising safety or functionality.

Since the original unit is repaired, all critical data—such as the vehicle identification number (VIN) and the specific coding for your vehicle’s equipment—remains intact. After repair, the device can be easily reinstalled using a “plug-and-play” approach; costly reprogramming at an authorized dealer is not required.

Moreover, refurbishment is a sustainable solution that conserves resources and helps avoid electronic waste. Airbag24 provides 2 years' statutory liability for defects on every repair performed.

How does repair work at Airbag24?

After sending the removed control unit A2049013702 to Airbag24, our technicians conduct a thorough analysis. The repair process includes erasing crash data, replacing defective components, and performing a final functional test before returning the unit ready for installation.

First, the faulty control unit should be removed by a qualified workshop. It is advisable to include a completed repair form with the package, and ideally a diagnostic report showing the read-out fault codes.

Upon arrival at Airbag24, the unit undergoes a comprehensive electronic inspection. Specialized technicians erase stored crash data and repair identified hardware defects at the component level.

Following successful refurbishment, the control unit is tested on a bench to ensure flawless operation across all systems. This guarantees reliable performance after reinstallation.

The repaired unit is shipped back to you. After installation, you may need to clear fault memory in other control units within the vehicle. You receive 2 years' statutory liability for defects on the repair.