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

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

The airbag control unit AB39-14B321-CJ is the control unit of the restraint system (SRS) of Ford. It evaluates signals from the crash sensors and decides in a crash whether airbags or seatbelt pretensioners deploy.

In doing so it monitors the system during normal driving too. It indicates any faults it finds via the airbag warning light; after an accident it stores crash data and locks itself.

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

The most common cause is crash data stored after an accident, even if no airbag has deployed, which cannot be erased with a normal diagnostic tool. Other causes are ageing, cold solder joints, moisture and corrosion, as well as voltage spikes.

In detail, these points come into consideration:

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

Which cause applies in each case is shown only by the examination of the unit.

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

The airbag warning light in the instrument cluster indicates the fault; it stays on permanently or intermittently. A diagnostic tool may then find no connection to the control unit, and airbags and seatbelt pretensioners may possibly not deploy in an emergency.

The signs in detail:

• airbag warning light stays on permanently or intermittently
• fault message in the instrument cluster
• diagnostic tool receives no connection to the control unit
• fault memory cannot be cleared

A warning light that appears only intermittently should also be checked.

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

This information applies to vehicles of the brand Ford. The control unit AB39-14B321-CJ is fitted in these vehicles: Ford Ranger 3 (2011-2015), 3 1st Facelift (2016-2019) and 3 2nd Facelift (2019-2023).

The vehicles at a glance:

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

Compare the part number on the label of the removed unit with the number on this page. This only ensures that you have the correct unit in front of you. Also have the fault memory read out beforehand; only that result shows whether the control unit itself or 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-CJ work?

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

Airbag24 examines the unit on the test bench, replaces defective components, deletes stored crash data and carries out a function test. After that your own unit is returned to you.

Processing at Airbag24 usually takes 3–4 working days. This time covers only the examination, repair and testing, not your steps or the dispatch. 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-CJ get to Airbag24?

You send the unit 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 into the parcel and pack the control unit shock-proof.