Airbag control unit with part number 77960-SDN-A820-M1

What does the airbag control unit 77960-SDN-A820-M1 do?

The airbag control unit 77960-SDN-A820-M1 is the central control unit of the restraint system (SRS) for Honda. It processes the signals from the crash sensors and decides in an accident which airbags and seatbelt pretensioners are triggered.

This decision is made within fractions of a second. At the same time, the control unit continuously checks the entire system and reports faults via the airbag warning light in the instrument cluster.

After an accident, it stores crash data and locks itself.

Why does the control unit 77960-SDN-A820-M1 fail?

The most common cause is crash data stored after an accident, which is present even when no airbag has fired. Aged components, cold solder joints, moisture on plug connections and voltage spikes are added causes.

Crash data cannot be erased with a usual diagnostic tool, so the fault remains visible in the unit. Airbag24 deletes the data during the repair.

Aged electronic components and cold solder joints can lead to changing error messages.

Moisture and corrosion on plug connections disturb the contact. Voltage spikes, for example from a weak battery or a jump start, put additional strain on the electronics.

How can you tell that the 77960-SDN-A820-M1 is defective?

A defect in the 77960-SDN-A820-M1 becomes apparent through the airbag warning light in the instrument cluster, through error messages, or through a lack of connection to the diagnostic tool. A fault memory that cannot be cleared confirms the suspicion.

Typical signs are:

• airbag warning light that is on constantly or intermittently
• error message in the instrument cluster
• diagnostic tool without connection to the control unit
• fault memory that cannot be cleared

In an emergency, airbags and seatbelt pretensioners may then fail to deploy.

Which vehicles is the 77960-SDN-A820-M1 fitted in?

The list applies to this part number. The control unit 77960-SDN-A820-M1 is fitted in these vehicles: Honda Accord 7th generation (2002-2008).

The selection in detail:

• Honda Accord 7th generation (2002-2008)

If the part number on the label of the removed unit matches this page, you have found the right unit. The comparison confirms nothing more. Have the fault memory read out beforehand, because only the log shows whether the control unit is defective or whether a connector or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 77960-SDA-306, 77960-SDN-C211-M1, 77960-SDR-A021-M4.

How does the repair of the 77960-SDN-A820-M1 work?

First have the fault memory read out and enclose the log. Then disconnect the battery, remove the 77960-SDN-A820-M1, create the repair order online and send the unit in well packed.

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

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-SDN-A820-M1 get to Airbag24?

You send the control unit 77960-SDN-A820-M1 to Airbag24 as a parcel, or you book a UPS collection for an extra charge. The return after the repair is made by UPS.

Enclose the printed repair order in the parcel. Pack the unit shockproof, so that it arrives undamaged.