Airbag control unit with part number LK4T-14B321-DE

What does the airbag control unit LK4T-14B321-DE do?

In the Ford the airbag control unit LK4T-14B321-DE ensures that the restraint system (SRS) responds at the right time. It receives the measurements from the crash sensors, selects in an impact which airbags and seatbelt pretensioners are triggered, and monitors the entire system. It reports faults via the airbag warning light.

The decision to trigger is made within a few milliseconds. The unit is therefore designed for fast and reliable evaluation.

After an accident the control unit stores crash data and locks itself in the process.

Why does the control unit LK4T-14B321-DE fail?

Most often the cause lies in crash data that remain in the memory after an accident, even if no airbag has deployed. A standard diagnostic tool cannot remove this data. Other causes are aged components, cold solder joints, moisture and corrosion on plug connections, and voltage spikes.

Crash data do not automatically mean that the unit is damaged. Airbag24 erases them during the repair.

The other causes act rather gradually. Electronic components change over time, solder joints can become brittle, and moisture or corrosion attacks the contacts. Voltage spikes, for example from a weak battery or a jump start, put additional strain on the electronics.

How can you tell that the LK4T-14B321-DE is defective?

Typical signs are the airbag warning light in the instrument cluster, which lights up permanently or intermittently, and a fault message in the instrument cluster. A diagnostic tool without connection to the control unit and a fault memory that cannot be cleared also indicate a fault.

A fault is therefore displayed and cannot be overlooked when the warning light comes on.

In an emergency, airbags and seatbelt pretensioners may possibly fail to deploy as a result. A warning light is therefore a reason to have the system checked.

• airbag warning light that stays on permanently
• airbag warning light that only lights up intermittently
• fault message in the instrument cluster
• no connection between the diagnostic tool and the control unit
• fault memory that cannot be cleared

Which vehicles is the LK4T-14B321-DE fitted in?

The airbag control unit LK4T-14B321-DE is fitted in these vehicles: Ford Transit 7 ’14 (from 2014).

The list below shows the vehicles recorded for this part number.

• Ford Transit 7 ’14 (from 2014)

Separate steps make sense here. Compare the part number on the label of the removed unit with this page; that way you know it is the right unit. Also have the fault memory read out, because only this result shows whether the control unit is defective or whether a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers BK2T-14B321-BF, BK3T-14B321-AC, DT1T-14B321-DF, KT1T-14B321-KD, LK4Z-14B321-C, LK4Z-14B321-E.

How does the repair of the LK4T-14B321-DE work?

At Airbag24 the processing usually takes 3–4 working days. Your steps come before that: read out the fault memory and enclose the log, disconnect the battery and only then remove the control unit. Then create the repair order online.

Pack the unit well and send it in. Airbag24 checks it on the test bench, replaces defective components, erases stored crash data and carries out a function test. Afterwards your own unit is returned to you.

Our repairs come with 2 years' statutory liability for defects. The repaired control unit comes back with all vehicle data and is ready for use as soon as it is refitted — no coding or programming is required.

How does the control unit LK4T-14B321-DE get to Airbag24?

Either you send the unit in as a parcel, or you book a UPS collection for an additional charge. Airbag24 sends the repaired unit back to you by UPS.

Do not forget the printed repair order in the parcel, and pack the unit shock-proof.