Airbag control unit with part number AB39-14B321-FB

What does the airbag control unit AB39-14B321-FB do?

The airbag control unit AB39-14B321-FB coordinates the restraint system (SRS) for Ford. It evaluates the crash sensors, decides within milliseconds in the event of an accident on airbags and seatbelt pretensioners, and monitors the system permanently. It shows faults via the airbag warning light.

Monitoring covers all involved components, whose connections the unit checks continuously. It stores irregularities in the fault memory.

After an accident it stores crash data and locks itself. The entire evaluation therefore lies in this one unit.

Why does the control unit AB39-14B321-FB fail?

The most common cause is crash data from an accident, even if no airbag was triggered; a normal diagnostic tool cannot delete it. Other causes include aged electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes.

Crash data remains stored even if no airbag fired in the accident. The fault therefore stays visible in the unit until the repair.

The other causes are everyday electronics problems: components age, solder joints can go cold, and moisture attacks plug connections. Voltage spikes, for example from a weak battery or jump-starting, add further strain to the circuits.

How can you tell that the AB39-14B321-FB is defective?

A defect shows up on the airbag warning light, which lights up permanently or intermittently, as a fault message in the instrument cluster, and as a missing connection to the diagnostic tool. A fault memory that cannot be cleared also belongs to this. In a real emergency, airbags and seatbelt pretensioners may then fail to trigger.

The warning light in the instrument cluster reports a fault as soon as the system detects it. Whether it lights up permanently or only intermittently is secondary for the test.

Have the finding checked promptly, because the light already reports the fault.

Which vehicles is the AB39-14B321-FB fitted in?

The airbag control unit AB39-14B321-FB is fitted in these vehicles: Ford Ranger 3 (2011-2015), 3 1st Facelift (2016-2019) and 3 2nd Facelift (2019-2023). This information lets you match the unit to the right vehicle.

The following vehicles are on record for this part number:

• Ford Ranger 3 (2011-2015)
• Ford Ranger 3 1st Facelift (2016-2019)
• Ford Ranger 3 2nd Facelift (2019-2023)

Before removal, compare the part number on the label of the unit with this page, so you know you have the right unit. Also have the fault memory read out, because only the result shows whether the control unit is defective or a plug or a cable is the cause.

For the same vehicles, we also repair control units with the part numbers AB3914B321CF, KB3T-14B321-BD.

How does the repair of the AB39-14B321-FB work?

First have the fault memory read out and enclose the log. Then disconnect the battery and only then remove the control unit. Online, create a repair order and send the unit in well packed; Airbag24 usually needs 3–4 working days for testing, repair and functional testing.

At Airbag24 the unit is examined on the test bench and defective components are repaired. Stored crash data is deleted at Airbag24, followed by a functional test.

Afterwards your own 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 AB39-14B321-FB get to Airbag24?

You send the control unit AB39-14B321-FB as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 sends the unit back to you by UPS.

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