Airbag control unit with part number 77960-SDN-A831-M1

What does the airbag control unit 77960-SDN-A831-M1 do?

The airbag control unit 77960-SDN-A831-M1 controls the restraint system (SRS) of Honda. It evaluates the signals from the crash sensors, selects in an accident, within a fraction of a second, the triggers for airbags and seatbelt pretensioners, and monitors the system continuously. After an accident it locks itself.

The evaluation is based on acceleration and the course of the impact, not on a single measured value. The unit reports faults in the system via the airbag warning light in the instrument cluster. After an accident it also stores crash data.

Why does the control unit 77960-SDN-A831-M1 fail?

The failure is most often caused by crash data stored after an accident, even if no airbag was triggered. A normal diagnostic tool cannot erase this data.

However, a failure can also have other causes. Typical are:

• electronic components that age over time
• cold solder joints inside the housing
• moisture and corrosion on the plug connections
• voltage spikes, for example with a weak battery or after a jump start

Which cause applies in the specific case is shown only by the examination of the removed unit. A suspicion alone is not enough for that.

How can you tell that the 77960-SDN-A831-M1 is defective?

A defect in the 77960-SDN-A831-M1 can show up through the airbag warning light in the instrument cluster, which stays on permanently or intermittently, through a fault message, or because the diagnostic tool gets no connection to the control unit. In an emergency, airbags and seatbelt pretensioners may then fail to trigger.

Typical signs include an airbag warning light that stays on permanently or only intermittently. Likewise, a fault message in the instrument cluster or a fault memory that cannot be cleared indicates a defect. A missing contact to the diagnostic tool is also a warning sign.

These symptoms are indications, but not yet proof. Therefore clarify with the fault memory beforehand whether the control unit itself is affected or a plug or cable.

Which vehicles is the 77960-SDN-A831-M1 fitted in?

The 77960-SDN-A831-M1 is fitted in these vehicles: Honda Accord 7th generation (2002-2008).

The following vehicles currently belong to this part number:

• Honda Accord 7th generation (2002-2008)

Compare the part number on the label of the removed unit with this information. Have the fault memory read out beforehand, so it is clear whether the control unit is really affected and not a plug or a cable.

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-A831-M1 work?

First read out the fault memory and prepare the log, then disconnect the battery and remove the 77960-SDN-A831-M1. Then create a repair order online and send the unit in well packed. Afterwards Airbag24 repairs it, and your own unit is sent back.

When removing the unit, take care not to damage it, and enclose the fault memory log with the parcel. Without this log an important point of reference is missing during the examination.

At Airbag24 the unit is examined on the test bench, defective components are replaced, stored crash data is erased and a functional test is carried out. Processing generally takes 3–4 working days and covers only this testing, repairing and testing.

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-A831-M1 get to Airbag24?

You send the control unit 77960-SDN-A831-M1 as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 sends the unit back by UPS.

Put the printed repair order into the parcel and pack the control unit shock-resistant.