Airbag control unit with part number 77960-TVA-Y321-M4

What does the airbag control unit 77960-TVA-Y321-M4 do?

The airbag control unit 77960-TVA-Y321-M4 is the central control unit of the restraint system (SRS) for Honda. It evaluates the signals from the crash sensors, decides within milliseconds in a crash which airbags and seatbelt pretensioners are triggered, and monitors the system continuously. After a crash it stores crash data and locks itself; the lock is only lifted by the repair.

Faults become visible via the airbag warning light in the instrument cluster. This display is the starting point of every check.

Why does the control unit 77960-TVA-Y321-M4 fail?

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

The crash data remains stored until Airbag24 deletes it during the repair. After that the unit works normally again, provided no other cause is present.

The other causes take effect over a longer period. Solder joints and plug contacts age, moisture attacks connections, and voltage peaks can strain circuits when the battery is weak.

How can you tell that the 77960-TVA-Y321-M4 is defective?

The airbag warning light in the instrument cluster stays on permanently or intermittently, a fault message appears in the instrument cluster, the diagnostic tool finds no connection to the control unit, or the fault memory cannot be cleared. In a real crash, airbags and seatbelt pretensioners may then fail to deploy.

The light therefore means that the system has detected a fault, and it does not go out merely because the vehicle is driven normally. A lit light calls for a prompt check.

Which vehicles is the 77960-TVA-Y321-M4 fitted in?

The control unit 77960-TVA-Y321-M4 is fitted in these vehicles: Honda Accord 10th generation (2017-2024).

The following overview shows which vehicles this unit is intended for.

• Honda Accord 10th generation (2017-2024)

Compare the part number on the label with this page before removal. That only ensures that you have the right unit. Also have the fault memory read out, because only that 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-T3L-A012-M1, 77960-T3L-C012-M4, 77960-T3L-C020-M4, 77960-T3L-C030-M4, 77960-T3L-F012-M4, 77960-T3L-F020-M4.

How does the repair of the 77960-TVA-Y321-M4 work?

Read out the fault memory first and enclose the log. Then disconnect the battery and only then remove the control unit 77960-TVA-Y321-M4. Next, create a repair order online and pack the unit well for shipping; Airbag24 needs 3–4 working days as a rule for the check, repair and function test.

Airbag24 examines the unit on the test bench, repairs defective components, deletes stored crash data and carries out a function test. Only then is your own unit sent back 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-TVA-Y321-M4 get to Airbag24?

You send the control unit 77960-TVA-Y321-M4 as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 sends the unit back to you by UPS.

Put the printed repair order into the parcel and pack the unit shockproof.