Airbag control unit with part number DM5T 14B321 SA

What is the function of the Airbag Control Unit DM5T 14B321 SA?

The airbag control unit with part number DM5T 14B321 SA is the central control module for the occupant protection system in the second-generation Ford Grand C-Max (2010–2019). It continuously monitors data from crash sensors, processes it in real time, and is responsible for deploying airbags and seatbelt pretensioners in the event of a collision.

As the “brain” of the passive safety system, this control unit determines within milliseconds whether and which restraint systems need to be activated to provide optimal protection for vehicle occupants.

It is specifically designed for use in the Ford Grand C-Max Mk2, including facelift models from 2015 onward. Proper functioning of this component is essential for vehicle safety.

This control unit is also known under alternative part numbers such as DM5T14B321EH, DM5T14B321RA, AM5T14B321AG, or 285011577. Compatibility is always confirmed by the part number printed directly on the device.

Why does the DM5T 14B321 SA control unit fail?

The most common cause of failure for the DM5T 14B321 SA control unit is the storage of crash data after an accident. For safety reasons, this data permanently disables the unit’s functionality. Other causes include internal electronic malfunctions that result in communication loss or non‑erasable fault codes.

Following a collision—even minor ones—the control unit irrevocably writes crash data into its internal memory. This process deactivates the entire airbag system to prevent erroneous deployment in the future, rendering the vehicle unsafe for continued operation.

In addition to stored crash data, internal component failures can also occur. These often manifest as the control unit no longer responding to diagnostic requests or reporting persistent error codes that cannot be cleared using standard workshop scanners.

Such a defect poses a significant safety risk, as the protective functions of airbags and seatbelt pretensioners are no longer guaranteed. Professional repair is therefore indispensable to restore full functionality of the restraint system.

How do you recognize a defect in the DM5T 14B321 SA?

A defect in the DM5T 14B321 SA control unit typically presents itself through a constantly illuminated or intermittently flashing airbag warning light on the instrument cluster. Additional clear indicators include persistent fault codes stored in the vehicle’s diagnostic memory that cannot be erased, as well as a lack of communication with diagnostic equipment.

The most obvious symptom for the driver is the persistently lit airbag warning light, signaling a critical fault in the restraint system that does not extinguish even after restarting the vehicle.

In the workshop, the defect reveals itself via specific fault codes pointing to either an internal malfunction of the control unit or stored crash data. A distinctive feature is that these errors cannot be cleared using conventional diagnostic tools.

In some cases, the control unit becomes completely inaccessible to diagnostic equipment. This total loss of communication makes OBD‑based fault analysis impossible and confirms a severe internal defect within the component.

In which models is the DM5T 14B321 SA installed?

The airbag control unit DM5T 14B321 SA, along with its compatible variants, is specifically designed for the second-generation Ford Grand C-Max. This includes both pre-facelift models from 2010 to 2015 and the revised facelift versions produced from 2015 to 2019.

At Airbag24, we repair the control unit with part number DM5T 14B321 SA for the following Ford vehicle models:

Ford Grand C-Max (2nd Generation, model years 2010–2015)

Ford Grand C-Max (2nd Generation Facelift, model years 2015–2019)

To ensure exact compatibility, it is crucial to verify the part number directly from the label affixed to the removed control unit. In case of discrepancies or uncertainties, consultation is recommended.

How does the control unit repair process work at Airbag24?

Professional repair at Airbag24 begins with the submission of the removed control unit. Our technicians perform an electronic analysis, reprogram the device to erase crash data and internal faults, thereby restoring full functionality. A final functional test guarantees flawless operation.

Upon receipt of your control unit at Airbag24, a proven repair procedure follows. First, the unit undergoes a thorough diagnosis to confirm reported faults.

The core of the repair lies in reprogramming the control unit using specialized hardware and software. During this process, all stored crash data is completely erased, and the internal fault memory is reset, effectively restoring the device to its factory settings.

Following this, each repaired control unit undergoes a comprehensive functional test. We ensure that communication operates flawlessly and that no errors remain stored. After reinstalling the unit in the vehicle, the airbag warning light can be cleared, and the system is fully operational once again.

We provide 2 years' statutory liability for defects on all repairs performed.