Airbag control unit with part number LL1T-14B321-BB

What does the airbag control unit LL1T-14B321-BB do?

The airbag control unit LL1T-14B321-BB is the central control unit of the restraint system (SRS) of Ford. It evaluates the crash sensors, determines in an accident within milliseconds which airbags and seatbelt pretensioners are triggered, and keeps the system in view.

The control unit reports faults in the system via the airbag warning light in the instrument cluster. The check takes place continuously, regardless of whether you are driving.

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

Why does the control unit LL1T-14B321-BB fail?

The most common cause is crash data stored after an accident, even if no airbag has fired. A standard diagnostic tool cannot erase it. Other causes are aged electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes, for example from a weak battery or jump-starting.

Airbag24 erases the crash data during the repair, so that it is no longer stored afterwards.

The other causes concern the electronics and their connections. Solder joints that were made cold from the start can come loose, and moisture allows contacts to corrode.

How can you tell that the LL1T-14B321-BB is defective?

The airbag warning light lights up permanently or intermittently in the instrument cluster, an error message also appears there, the diagnostic tool gets no connection to the control unit, and the fault memory cannot be cleared.

While these signs persist, the airbags and seatbelt pretensioners may fail to deploy in an emergency. For a precise assessment, it is worthwhile to have the fault memory read out.

The warning light is one of the indications you should watch while driving, because it reports the finding first.

Which vehicles is the LL1T-14B321-BB fitted in?

The control unit LL1T-14B321-BB is fitted in these vehicles: Ford Expedition 1 UN93 (1997-2002).

The vehicles are listed below as an overview.

• Ford Expedition 1 UN93 (1997-2002)

Comparing the part number on the label of the removed unit with this page shows only that it is the right unit. Have the fault memory read out beforehand, because only the 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 FL1T-14B321-AC, FL1T-14B321-BB, JL1T-14B321-BA, LL1T-14B321-AA.

How does the repair of the LL1T-14B321-BB work?

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

Airbag24 checks the unit on the test bench, replaces defective components, erases the stored crash data and carries out a function test. The unit then goes back to you.

The processing time is usually 3–4 working days, and the sequence of the first steps is fixed for safety reasons.

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 LL1T-14B321-BB 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 by UPS. Enclose the printed repair order in the parcel and pack the control unit shock-proof.

A suitable carton with padding protects the unit from knocks during transit.