Airbag control unit with part number 77960-SFM-J420-M3

What does the airbag control unit 77960-SFM-J420-M3 do?

The airbag control unit 77960-SFM-J420-M3 coordinates the airbags and seatbelt pretensioners of Honda. It evaluates the crash sensors, decides on triggering in an accident and continuously monitors the system.

If there is a fault, the unit reports it via the airbag warning light. After an accident it also stores crash data and locks itself.

Why does the control unit 77960-SFM-J420-M3 fail?

The most common cause is stored crash data, even without an airbag deployment. A normal diagnostic tool cannot erase it; Airbag24 erases it during the repair. Other causes include aged components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes, for example from a weak battery.

The crash data stays in the control unit's memory until the repair erases it.

The remaining causes are wear of the electronics and environmental influences at the connections. Components age, solder joints can become brittle, and moisture attacks contacts.

Voltage spikes arise when starting with a jump start or with a weak battery. Such spikes can stress components.

How can you tell that the 77960-SFM-J420-M3 is defective?

The airbag warning light in the instrument cluster stays on permanently or intermittently as soon as there is a defect on the 77960-SFM-J420-M3. Fault messages, a missing connection to the diagnostic tool and a fault memory that cannot be cleared may also occur. In an emergency, airbags and seatbelt pretensioners may then not trigger.

The light gives you a clear signal that the system has found a fault. So do not postpone an inspection; act promptly.

Which vehicles is the 77960-SFM-J420-M3 fitted in?

The 77960-SFM-J420-M3 is fitted in these vehicles: Honda Freed 1st generation (2008-2016). The label on the removed unit tells you whether your vehicle is among them.

The list of vehicles:

• Honda Freed 1st generation (2008-2016)

A comparison of the part number on the label with this page only shows whether you have the right unit, nothing more. Have the fault memory read out before removal, because only that result shows whether the control unit is defective or whether a plug or cable is the cause.

How does the repair of the 77960-SFM-J420-M3 work?

You have the fault memory read out and enclose the log. Then you disconnect the battery and only afterwards remove the control unit. Online you create the repair order and pack the 77960-SFM-J420-M3 well before sending it in. In general, you should allow 3–4 working days at Airbag24 for inspection and repair.

Airbag24 checks the unit on the test bench, repairs defective components, erases stored crash data and carries out a function test. The team then returns your own unit.

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 77960-SFM-J420-M3 get to Airbag24?

You send the 77960-SFM-J420-M3 either as a parcel or have it collected by UPS for an extra charge. Airbag24 then sends the repaired unit back by UPS.

Put the printed repair order in the parcel. The unit should be packed shock-proof.