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

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

The airbag control unit 77960-SYY-J420-M3 is the central control unit of the restraint system (SRS) for Honda. It evaluates the signals from the crash sensors and, in a crash, decides within milliseconds which airbags and seatbelt pretensioners are triggered.

While driving, the unit monitors the entire system without interruption. If it detects a fault, it reports it via the airbag warning light in the instrument cluster.

After an accident the control unit stores crash data and locks itself. Only the repair lifts this lock.

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

Stored crash data is the most common cause on the 77960-SYY-J420-M3, even if no airbag was triggered, and a normal diagnostic tool cannot erase it. Other causes include aged components, dry solder joints, moisture and corrosion at plug connections, and voltage spikes. Airbag24 clears the crash data during the repair.

The data remains stored in the unit until it is cleared during the repair. This applies regardless of whether an airbag was triggered.

Voltage spikes arise, for example, from a weak battery or a jump start, and strain the electronics.

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

A defect in the 77960-SYY-J420-M3 shows as the airbag warning light in the instrument cluster staying on permanently or intermittently, as an error message in the instrument cluster, and as the diagnostic tool being unable to connect to the control unit. A fault memory that cannot be cleared is also a sign.

The light therefore indicates the defect directly. As soon as it comes on, reading the fault memory is the right next step.

While the fault persists, airbags and seatbelt pretensioners may fail to trigger in an emergency. It is therefore sensible to have the warning checked promptly.

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

The airbag control unit 77960-SYY-J420-M3 is fitted in these vehicles: Honda Freed 1st generation (2008-2016).

The following overview shows the vehicle data associated with this part number.

• Honda Freed 1st generation (2008-2016)

Before sending, compare the part number on the label of the removed unit with this page; this only confirms that it is the correct unit. Also have the fault memory read out in advance, because only this record 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 77960-SFM-J412-M3, 77960-SFM-J420-M3.

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

First have the fault memory read out and enclose the record with the parcel. Then disconnect the battery and only afterwards remove the control unit. Next create a repair order online and send the unit off securely packed.

Airbag24 checks the 77960-SYY-J420-M3 on the test bench, replaces defective components, clears the stored crash data and carries out a function test. Processing at Airbag24 usually takes 3–4 working days.

After that your own, repaired unit is returned to you. 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-SYY-J420-M3 get to Airbag24?

You send the control unit 77960-SYY-J420-M3 as a parcel to Airbag24 or book a UPS collection for an extra charge. After the repair, Airbag24 returns the unit to you by UPS.

Print the repair order and put it in the parcel. Pack the unit shock-proof before handing it over.