Airbag control unit with part number 77960-TWD-Z020-M4

What does the airbag control unit 77960-TWD-Z020-M4 do?

The control unit 77960-TWD-Z020-M4 is the switching centre of the SRS restraint system of Honda. It evaluates the crash sensors, determines in an accident which airbags and seatbelt pretensioners fire, and monitors the system continuously. After an accident it stores crash data and locks itself.

It indicates detected faults via the airbag warning light, so that the driver notices the fault.

Why does the control unit 77960-TWD-Z020-M4 fail?

An important reason is the storing of crash data after an accident, even if no airbag has triggered. An ordinary diagnostic tool cannot delete it; Airbag24 deletes it during the repair. Ageing components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes from a weak battery or a jump start are further causes.

Voltage spikes are surges of current that stress the electronics when the on-board voltage briefly drops.

Without testing, it is not possible to say which of these causes actually applies.

How can you tell that the 77960-TWD-Z020-M4 is defective?

The airbag warning light in the instrument cluster shows the defect by lighting constantly or intermittently. In addition, an error message may appear in the instrument cluster, the diagnostic tool may lose contact with the control unit, or the fault memory cannot be cleared. Airbags and seatbelt pretensioners may then possibly fail to deploy in an emergency.

This warning must be taken seriously and calls for a prompt check.

Which vehicles is the 77960-TWD-Z020-M4 fitted in?

The 77960-TWD-Z020-M4 is fitted in the following vehicles: Honda Accord 10th generation (2017-2024).

The vehicle overview follows here:

• Honda Accord 10th generation (2017-2024)

Compare the number on the label of the removed unit with this page; this only confirms that it is the right unit. Have the fault memory read out beforehand, because only it shows whether the control unit 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-TWD-Z020-M4 work?

The fault memory is read out first and the log is enclosed. Then you disconnect the battery and only then remove the control unit. The work at Airbag24, i.e. testing, repair and functional check, usually takes 3–4 working days.

Then create the repair order online and send the unit in well packed. There Airbag24 examines it, replaces defective parts, deletes stored crash data and tests the function. Afterwards the unit comes 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-TWD-Z020-M4 get to Airbag24?

A parcel or a UPS collection booked via UPS brings the unit to Airbag24; the collection is available for an extra charge. UPS takes care of the return after the repair.

The printed repair order goes into the parcel, and the control unit is packed shock-resistant.