Airbag control unit with part number 77960-3D4-A820-M2

What does the airbag control unit 77960-3D4-A820-M2 do?

The airbag control unit 77960-3D4-A820-M2 controls the SRS restraint system at Honda. It determines from the crash sensors, in fractions of a second, which airbags and seatbelt pretensioners to trigger, and checks the system continuously.

It also detects faults and indicates them via the airbag warning light.

If it has registered an accident, the unit writes crash data to memory and then locks itself.

Why does the control unit 77960-3D4-A820-M2 fail?

Stored crash data from an earlier accident is the most common cause for control unit 77960-3D4-A820-M2, even when no airbag has deployed. Aged components, cold solder joints, moisture and corrosion on plugs, as well as voltage spikes are also possible.

A normal diagnostic tool cannot remove this data.

Voltage spikes, for example from a weak battery or jump start, stress the electronics just as moisture does.

How can you tell that the 77960-3D4-A820-M2 is defective?

A defect shows up as the airbag warning light staying on permanently or flickering intermittently, as a fault message in the instrument cluster, as a lack of connection to the diagnostic tool and as a fault memory that cannot be cleared. In an emergency, airbags and seatbelt pretensioners may then not deploy.

• The airbag warning light in the instrument cluster stays on permanently or flickers intermittently.
• A fault message appears in the instrument cluster.
• The diagnostic tool cannot establish a connection to the control unit.
• The fault memory cannot be cleared.

The warning light and the fault message are the two signs drivers are most likely to see in everyday driving.

Which vehicles is the 77960-3D4-A820-M2 fitted in?

Vehicles of Honda in which the control unit 77960-3D4-A820-M2 is fitted are: Honda CR-V 6 (from 2022).

An overview of the affected vehicles is shown here:

• Honda CR-V 6 (from 2022)

Compare the label on the removed unit with this page; then you know that it is the right unit. Have the fault memory read out before you send the unit in, because the result shows whether the control unit is defective or whether a plug or cable is the cause.

How does the repair of the 77960-3D4-A820-M2 work?

First have the fault memory read out and attach the log. Then disconnect the battery, remove the control unit and create a repair order online, with which you send it in.

Airbag24 checks the unit on the test bench, replaces defective components, deletes stored crash data and carries out a function test. The own unit goes back to you afterwards.

Processing at Airbag24 usually takes 3–4 working days. 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 77960-3D4-A820-M2 get to Airbag24?

You send in the unit as a parcel, or book a UPS collection for an extra charge. Airbag24 sends the control unit 77960-3D4-A820-M2 back to you by UPS after the repair.

The printed repair order belongs in the parcel, and the unit must be packed shock-proof.