Airbag control unit with part number 77960-T70-H220-M4

What does the airbag control unit 77960-T70-H220-M4 do?

The airbag control unit 77960-T70-H220-M4 is the control unit of the restraint system (SRS) for Honda. It processes the data from the crash sensors, decides within milliseconds in an accident on the triggering of airbags and seatbelt pretensioners, and monitors the system at all times.

The warning light in the instrument cluster reports faults that the unit detects. The sensors supply only measured values; everything is processed and assessed in the control unit.

After an accident, the unit stores crash data and locks itself. The following sections describe causes and signs of a failure.

Why does the control unit 77960-T70-H220-M4 fail?

On the 77960-T70-H220-M4, stored crash data after an accident most often leads to failure, even without an airbag having fired. Other causes lie in ageing electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes.

Crash data cannot be erased with a normal diagnostic tool. The unit therefore keeps it, and that is precisely the problem the repair resolves.

Electronic components age, and solder joints can go cold over time. Moisture attacks plug connections, so the contact suffers.

Voltage spikes, for example when starting with an external power source or with a weak battery, additionally strain the unit.

How can you tell that the 77960-T70-H220-M4 is defective?

A defect in the 77960-T70-H220-M4 shows up through the airbag warning light, an error message in the instrument cluster, a missing connection to the diagnostic tool and a fault memory that cannot be cleared.

If the airbag warning light stays on permanently or intermittently, the system has detected a fault. The error message in the instrument cluster confirms this.

As long as the fault exists, airbags and seatbelt pretensioners may possibly not deploy in an emergency. A diagnostic tool without a connection and a fault memory that cannot be emptied are further indications of the condition.

Which vehicles is the 77960-T70-H220-M4 fitted in?

The control unit 77960-T70-H220-M4 is fitted in these vehicles: Honda HR-V 2nd generation (2015-2022).

These vehicles are recorded in the data for this part number:

• Honda HR-V 2nd generation (2015-2022)

Comparing the part number on the label of the removed unit with this page only ensures that it is the right unit. Also have the fault memory read out beforehand, because only that shows whether the control unit is faulty or whether a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 77960-3V0-A81, 77960-T7S-A21, 77960-T7S-A212-M2, 77960T7SK410M2.

How does the repair of the 77960-T70-H220-M4 work?

You first read out the fault memory of the 77960-T70-H220-M4 and enclose the log, then disconnect the battery. Afterwards remove the control unit, create the repair order online and send the unit in well packed.

The sequence must be followed for safety reasons, exactly as it is described.

Airbag24 examines the unit sent in on the test bench, replaces defective components, erases the crash data and carries out a function test. Processing usually takes 3–4 working days. Your own unit is then sent back.

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-T70-H220-M4 get to Airbag24?

You send the control unit 77960-T70-H220-M4 as a parcel, or you book a UPS collection for an extra charge. Airbag24 returns it by UPS after the repair.

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