Airbag control unit with part number 77960-3A2-A820-M2

What does the airbag control unit 77960-3A2-A820-M2 do?

The airbag control unit 77960-3A2-A820-M2 is the central control unit of the restraint system (SRS) for Honda. It evaluates the signals from the crash sensors, determines in an emergency within milliseconds the triggering of airbags and seatbelt pretensioners, and checks the system continuously.

It reports faults via the airbag warning light. After an accident it stores crash data and locks itself.

For these tasks the control unit works closely with sensors, wiring and triggering elements.

Why does the control unit 77960-3A2-A820-M2 fail?

For 77960-3A2-A820-M2 the most common cause is crash data stored after an accident, even if no airbag has triggered. In addition come aged components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes.

Crash data remains in memory until Airbag24 removes it during the repair; a normal diagnostic tool cannot do this.

The other causes concern the electronics and their connections: components age, solder joints become cold and moisture penetrates plug connections. Voltage spikes, for example from a weak battery or a jump start, can additionally weaken components.

How can you tell that the 77960-3A2-A820-M2 is defective?

A defect on the 77960-3A2-A820-M2 shows up as the airbag warning light in the instrument cluster, a fault message in the instrument cluster, no connection to the diagnostic tool, and a fault memory that cannot be cleared.

• Airbag warning light in the instrument cluster lights constantly or intermittently
• Fault message in the instrument cluster
• Diagnostic tool fails to establish a connection to the control unit
• Fault memory cannot be cleared

The airbag warning light may light constantly or only intermittently; in both cases a fault in the restraint system has been detected.

Airbags and seatbelt pretensioners may possibly not trigger in an emergency while the fault persists. Therefore have the system checked promptly.

Which vehicles is the 77960-3A2-A820-M2 fitted in?

The control unit 77960-3A2-A820-M2 matches the stored models of Honda. It is fitted in these vehicles: Honda Civic 10th generation (2015-2022).

This list shows the known vehicles.

• Honda Civic 10th generation (2015-2022)

Comparing the part number on the label of the removed unit with this page only confirms that it is the correct unit. Whether the control unit is defective or a plug or cable is the cause is clarified only by the fault memory read out beforehand.

For the same vehicles, we also repair control units with the part numbers 77960-SMG-G014-M1, 77960-TBA-A01, 77960-TBA-A02, 77960-TBA-A03, 77960-TBA-A04, 77960-TBA-A05.

How does the repair of the 77960-3A2-A820-M2 work?

First have the fault memory read out and enclose the log, then disconnect the battery and remove the control unit 77960-3A2-A820-M2. Then create the repair order online and send in the well-packed unit. At Airbag24, testing, repairing and function testing usually take 3–4 working days.

The sequence is mandatory for safety reasons. The control unit is therefore removed only after the battery has been disconnected.

At Airbag24 the unit is checked on the test bench, defective components are replaced, the crash data is deleted and a function test is carried out.

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 77960-3A2-A820-M2 get to Airbag24?

You send the control unit 77960-3A2-A820-M2 in as a parcel or book a UPS collection for an extra charge. After the repair Airbag24 sends the control unit back by UPS.

Print out the repair order and put it in the parcel; pad the unit shock-resistant.