Airbag control unit with part number CM5T-14B321-FB

What does the airbag control unit CM5T-14B321-FB do?

The airbag control unit CM5T-14B321-FB controls the restraint system (SRS) of Ford. It evaluates the signals from the crash sensors and decides in an accident, within milliseconds, which airbags and seatbelt pretensioners are triggered.

During operation, it monitors the entire system. If it detects a fault, it shows this via the airbag warning light and a message in the instrument cluster.

After an accident, it stores crash data and locks itself.

Why does the control unit CM5T-14B321-FB fail?

The most common cause is crash data stored after an accident, even if no airbag has deployed; a standard diagnostic tool cannot erase it. Other causes include aged electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes.

The control unit records crash data as soon as it registers an accident. The data stays in memory even if no airbag has deployed.

The remaining causes act over time. Moisture penetrates plug connections, corrosion and cold solder joints disrupt contact, and the electronics age.

Voltage spikes, for example from a weak battery or when connecting a jump start, can additionally stress the electronics.

How can you tell that the CM5T-14B321-FB is defective?

The airbag warning light in the instrument cluster stays on permanently or intermittently, an error message appears, or the diagnostic tool finds no connection to the control unit. In that case, airbags and seatbelt pretensioners may possibly not deploy in an emergency.

Typical signs are:

• Airbag warning light stays on permanently or intermittently
• Error message in the instrument cluster
• Diagnostic tool receives no connection to the control unit
• Fault memory cannot be cleared

A lit warning light is a matter to be clarified promptly and is no trifle.

Which vehicles is the CM5T-14B321-FB fitted in?

The CM5T-14B321-FB is fitted in these vehicles: Ford Focus 3 ’11 (2010-2014) and 3 ’11 Facelift (2014-2018).

You will find the vehicles recorded for this part number in this overview:

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

On the one hand, compare the part number on the label of the removed unit with this page; this only ensures that it is the correct unit. On the other hand, have the fault memory read out beforehand. Only this result shows whether the control unit is defective or whether a connector 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 CM5T-14B321-FB work?

First have the fault memory read out and attach the log, then disconnect the battery and only then remove the control unit. Then create a repair order online and send the unit in well packed. Airbag24 checks it on the test bench, replaces defective components, erases stored crash data and carries out a function test.

This sequence is for your safety, so please do not deviate from it.

Processing at Airbag24 usually takes 3–4 working days.

Afterwards, your own, repaired unit comes back 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 CM5T-14B321-FB get to Airbag24?

You send the unit in as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 sends it back to you by UPS.

Put the printed repair order in the parcel and pack the unit shock-proof.