Airbag control unit with part number BK2T-14B321-AG

What is the function of the airbag control unit BK2T-14B321-AG?

The airbag control unit with part number BK2T-14B321-AG is the central control unit for the entire occupant safety system (SRS) in Ford Transit Custom and Ford Tourneo Custom models. It processes signals from crash and acceleration sensors to precisely deploy airbags and seatbelt pretensioners in the event of a collision. As an expensive original part, repair represents a cost-effective alternative.

As the “brain” of the safety system, this SRS ECU continuously monitors all connected components, including front, side, and head airbags, seatbelt pretensioners, seatbelt buckle detection, and all relevant vehicle sensors. In the event of a collision, the control unit determines within milliseconds which restraint systems must be activated to provide optimal protection for occupants.

The complexity of its electronics makes the device susceptible to specific internal faults, often signaled by error code U300049 in the diagnostic system. This code indicates an irreversible internal hardware or memory fault that disables the functionality of the entire airbag system.

Why does the BK2T-14B321-AG control unit fail? Typical defects

The most common cause of failure for the BK2T-14B321-AG control unit is stored crash data following an accident, which permanently locks the device. Other reasons include internal electronic malfunctions leading to error codes such as U300049, as well as moisture damage or issues with sensor communication that are permanently logged in the fault memory.

After a collision, so‑called crash data is irreversibly stored in the control unit’s memory. This is a manufacturer‑imposed safety measure designed to prevent reuse without professional inspection and repair. The unit becomes locked, and the airbag warning light remains illuminated.

Another frequent defect is an internal electronic malfunction, potentially caused by faulty components on the circuit board or problems with the internal EEPROM memory. Such failures often manifest as error code U300049 (internal fault), which cannot be cleared using standard workshop scanners.

External factors like penetrating moisture can also lead to corrosion and short circuits, damaging the electronics. It’s important to note that other part numbers—such as 285001955, 2T1T-14B321-AC, and BK2T-14B321-BF—are either identical or compatible and may exhibit the same fault patterns.

How do you recognize a defect in the BK2T-14B321-AG?

The clearest symptom is a continuously illuminated or intermittently flashing airbag warning light on the instrument cluster. Often, the control unit can no longer be accessed via a diagnostic tool, or non‑erasable error codes like U300049 appear. Messages such as “fuel shut-off valve defective” may also indicate a faulty airbag control unit.

The airbag warning light is the primary indicator of a problem in the restraint system, signaling that airbags and seatbelt pretensioners might not deploy—or might not deploy correctly—in the event of a crash.

A more serious symptom is the inability to communicate with the diagnostic tool. If the workshop cannot access the airbag control unit, this strongly suggests a deep‑seated internal fault within the control unit itself.

Stored error codes that cannot be erased are also clear evidence. In particular, error code U300049 (internal fault) or messages related to side‑impact sensors directly point to a problem within the control unit requiring professional repair.

In which Ford models is the BK2T-14B321-AG control unit installed?

The BK2T-14B321-AG airbag control unit is specifically used in Ford’s commercial vehicle and passenger transport series. It is installed in first‑generation Ford Transit Custom and Ford Tourneo Custom models, as well as their facelift variants.

At Airbag24, we repair the BK2T-14B321-AG control unit and compatible versions for the following models:

Ford Transit Custom 1 (model years 2012–2018)

Ford Transit Custom 1 Facelift (model years 2018–2023)

Ford Tourneo Custom 1 (model years 2012–2018)

Ford Tourneo Custom 1 Facelift (model years 2018–2023)

How is the BK2T-14B321-AG control unit professionally repaired?

Professional repair at Airbag24 aims to restore the original control unit to like-new condition through electronic means. The process includes expert erasure of crash data, correction of internal faults, and a final functional test. We offer 2 years' statutory liability for defects on every repair.

First, a thorough diagnosis at a certified automotive workshop is recommended to confirm that the fault truly lies within the control unit. If diagnostic reports or error codes are available, please attach them to your shipment to expedite analysis.

Upon receipt at Airbag24, our technicians perform a detailed electronic diagnostic. At the heart of the repair is reprogramming the memory to erase crash data and internal error codes (e.g., U300049). Defective electronic components are identified and replaced.

Subsequently, the device’s full functionality is thoroughly tested. Once reinstalled, the repaired control unit performs like a brand-new part and is ready for immediate use (plug-and-play). This repair is not only more cost-effective but also more sustainable than replacement.