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

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

The airbag control unit AB39-14B321-CH coordinates airbags and seatbelt pretensioners in the SRS restraint system of Ford. It evaluates the signals from the crash sensors and decides on triggering within milliseconds in an accident. While driving, it monitors the system continuously and reports faults via the airbag warning light.

To do so, it checks sensors, wiring and trigger circuits during operation and keeps detected faults in the fault memory.

After an accident the unit records crash data and locks itself.

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

The most common cause is crash data stored after an accident, even if no airbag has deployed. A normal diagnostic tool cannot erase it; Airbag24 erases it during the repair. Further causes that may come into consideration are aged electronic components, moisture, corrosion and voltage spikes.

Crash data arises even without an airbag deploying, because the unit already records the event.

Further causes at a glance:

• ageing of the electronic components
• cold solder joints
• moisture and corrosion at plug connections
• voltage spikes from a weak battery or a jump start

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

The airbag warning light in the instrument cluster stays on permanently or comes on only now and then, and an error message appears on the display. The diagnostic tool does not connect to the control unit, and the fault memory cannot be cleared. In an emergency, airbags and seatbelt pretensioners may then possibly not deploy.

Anyone who observes the warning light recognises a fault early. The light shows the defect as soon as the unit detects it.

Messages that appear only occasionally also need to be checked, as the fault memory can clarify them.

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

The control unit AB39-14B321-CH is fitted in these vehicles: Ford Ranger 3 (2011-2015), 3 1st Facelift (2016-2019) and 3 2nd Facelift (2019-2023). Check your vehicle against the vehicle documents before you act.

Here are the vehicles for which the unit is listed:

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

Comparing the part number on the label only confirms the right unit. Reading out the fault memory, by contrast, 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 AB3914B321CF, KB3T-14B321-BD.

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

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

Processing at Airbag24 usually takes 3–4 working days. This time frame refers exclusively to checking, repairing and testing.

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-CH get to Airbag24?

There are two options for shipping: your own parcel, or a UPS collection for an extra charge. The return is likewise by UPS. The printed repair order belongs in the parcel, and the unit is packed shock-proof.

A sturdy box with padding helps prevent damage to the housing.