Airbag control unit with part number LN15-14B321-BB

What does the airbag control unit LN15-14B321-BB do?

The airbag control unit LN15-14B321-BB is the central control unit of the SRS, the restraint system, in Ford vehicles. It evaluates the sensor system, determines within milliseconds in a crash whether airbags and seatbelt pretensioners are triggered, and monitors the system constantly. It reports detected faults via the airbag warning light.

The unit is part of a closed system whose condition it assesses continuously.

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

Why does the control unit LN15-14B321-BB fail?

The most common cause is crash data stored after an accident, even if no airbag has triggered; a normal diagnostic tool does not erase it. In addition there are ageing electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes, for example from a weak battery or a jump start.

Crash data is created in the control unit and stays in memory until specialists remove it. That is why a fault can occur although nothing can be seen on the vehicle.

The other causes act over time: components age, solder joints become brittle, and moisture attacks contacts. Voltage spikes add further strain to the electronics.

How can you tell that the LN15-14B321-BB is defective?

A defect shows up as the airbag warning light, which stays on permanently or only intermittently, and as an error message in the instrument cluster. Also, the diagnostic tool cannot reach the control unit, and the fault memory remains occupied. In an emergency, airbags and seatbelt pretensioners may then fail to trigger.

• Airbag warning light stays on permanently
• Airbag warning light lights up intermittently
• Error message in the instrument cluster
• No access from the diagnostic tool to the control unit
• Fault memory cannot be cleared

If you notice one of these signs, make the check your next step. The light is a clear signal and not a hint that can be ignored.

Which vehicles is the LN15-14B321-BB fitted in?

The airbag control unit LN15-14B321-BB is fitted in these vehicles: Ford EcoSport 2 Facelift (2015-2022).

Here are the vehicles known to us for this control unit:

• Ford EcoSport 2 Facelift (2015-2022)

First compare the part number on the label of the removed unit with this page. This only confirms that you have the right unit in front of you. Then have the fault memory read out, because it shows whether the control unit or a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers DN1T-14B321-EC, GN15-14B321-AF, GN15-14B321-GJ, GN1Z-14B321-AE, GN1Z-14B321-AK.

How does the repair of the LN15-14B321-BB work?

Before removal, read out the fault memory and attach the log. Then disconnect the battery, remove the control unit and create a repair order online. Typically 3–4 working days are planned at Airbag24 for checking, repairing and testing.

The sequence protects you during dismantling. Follow it exactly.

At Airbag24 the control unit goes on the test bench. There, defective components are replaced, the crash data is erased and a function test is run. Afterwards your own unit is returned.

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 LN15-14B321-BB get to Airbag24?

You send the unit as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 returns it by UPS. Put the printed repair order in the parcel and pack the unit shockproof.

Shockproof means the control unit is firmly embedded and padded all round.