Airbag control unit with part number 77960-TF0-J420-M3

What does the airbag control unit 77960-TF0-J420-M3 do?

The airbag control unit 77960-TF0-J420-M3 controls the SRS restraint system of the Honda vehicle. It processes the readings of the crash sensors and, in an impact, triggers the appropriate airbags and seatbelt pretensioners within milliseconds.

Between accidents the unit monitors the wiring, the sensors and its own electronics. A fault it detects is stored in the fault memory and shown via the airbag warning light in the instrument cluster.

After an accident it stores crash data and locks itself.

Why does the control unit 77960-TF0-J420-M3 fail?

The most common cause is crash data stored after an accident, even if no airbag was deployed. In addition, aged electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes from a weak battery or a jump start can cause the failure.

An ordinary diagnostic tool cannot remove this crash data. It therefore stays in memory, and Airbag24 erases it during the repair.

The other causes relate to the technology itself. Components age, solder joints become brittle over time, and moisture attacks the contacts. Voltage spikes arise, for example, when a jump start is needed.

How can you tell that the 77960-TF0-J420-M3 is defective?

A defect in the 77960-TF0-J420-M3 can be recognised by the airbag warning light in the instrument cluster, which stays on permanently or intermittently. In addition there is a fault message in the instrument cluster and problems when reading out the control unit.

• Airbag warning light stays on permanently
• Airbag warning light comes on intermittently
• Fault message in the instrument cluster
• Diagnostic tool cannot establish a connection
• Fault memory cannot be cleared

In that case airbags and seatbelt pretensioners may fail to trigger in an emergency. Take the warning seriously and arrange a check promptly.

Which vehicles is the 77960-TF0-J420-M3 fitted in?

The 77960-TF0-J420-M3 is fitted in these vehicles: Honda Jazz GE (2008-2015).

The assignment to models and years of construction is shown below.

• Honda Jazz GE (2008-2015)

Compare the part number on the label of the removed unit with this page. This only confirms that you have the right unit. The cause only becomes apparent in the fault memory, which you should have read out before removal, because only this log shows whether the control unit is defective or whether a plug or a cable is affected.

For the same vehicles, we also repair control units with the part numbers 5WK43461, 77960-SAA-G821-M1, 77960-SEG-G821-M1, 77960-TF0-G820-M3, 77960-TF0-G821.

How does the repair of the 77960-TF0-J420-M3 work?

First have the fault memory read out and enclose the log. Then disconnect the battery and only then remove the control unit. Finally, create a repair order online and pack the unit well before sending it in.

Airbag24 first checks the unit on the test bench, then repairs defective components and erases the stored crash data. A function test completes the work, after which the unit is returned to you.

The processing takes 3–4 working days, and this time covers only checking, repairing and testing. 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-TF0-J420-M3 get to Airbag24?

You send the control unit 77960-TF0-J420-M3 to Airbag24 as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 returns it to you by UPS.

Pack the printed repair order into the parcel and cushion the unit shockproof.