Airbag control unit with part number BM5T-14B321-CD

What does the airbag control unit BM5T-14B321-CD do?

The BM5T-14B321-CD is the airbag control unit of the restraint system (SRS) in Ford, that is, the point where all sensor data converge. In an accident it decides within milliseconds on the triggering of airbags and seatbelt pretensioners. After an accident it stores crash data and locks itself.

In addition, it checks the system continuously for faults and reports them via the airbag warning light.

The unit is not only a switching point but also a diagnostic point, so faults can be read out in a targeted way.

Why does the control unit BM5T-14B321-CD fail?

The most common cause is crash data stored after an accident, even without an airbag being triggered. Other causes are aged electronics, cold solder joints, moisture at plug connections and voltage spikes.

• Aged electronic components
• Cold solder joints
• Moisture and corrosion at plug connections
• Voltage spikes from a weak battery or jump-starting

A conventional diagnostic tool leaves crash data stored in the unit. Which of the causes named actually applies only becomes clear when the fault memory is read out.

How can you tell that the BM5T-14B321-CD is defective?

The airbag warning light lights up permanently or intermittently. In the event of a defect, an error message also appears in the instrument cluster, a diagnostic tool cannot reach the control unit, and the fault memory remains. Then airbags and seatbelt pretensioners may not trigger in an emergency.

The light checks itself when the ignition is switched on. If it stays on afterwards or comes on repeatedly, a check is needed.

A fault in a plug or cable can also trigger the display, so the light alone does not decide the cause.

Which vehicles is the BM5T-14B321-CD fitted in?

The control unit BM5T-14B321-CD is fitted in these vehicles: Ford Focus 3 ’11 (2010-2014) and 3 ’11 Facelift (2014-2018). The list refers to Ford.

You can see the assignment broken down in more detail here:

• Ford Focus 3 ’11 (2010-2014)
• Ford Focus 3 ’11 Facelift (2014-2018)

Comparing the part number of the removed unit with this page only clarifies whether it is the right unit. Have the fault memory read out before removal, because only this log shows whether the control unit itself is defective or whether a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 285011993, BM5T-14B321-CE, CM5T-14B321-CA, DM5T 14B321 SA, F1ET-14B321-CB.

How does the repair of the BM5T-14B321-CD work?

First have the fault memory read out and attach the log. Then disconnect the battery, remove the control unit, create the repair order online and send the unit in well packed.

Airbag24 tests the unit on the test bench, replaces defective components, erases stored crash data and carries out a function test. Then your own unit goes back to you.

Processing at Airbag24 usually takes 3–4 working days, and this time applies only to testing, repairing and function-checking.

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 BM5T-14B321-CD get to Airbag24?

You send the unit as a package, or you have it collected by UPS for an extra charge. Airbag24 returns the repaired unit to you by UPS.

The printed repair order goes into the package, and the unit is packed shockproof.