Airbag control unit with part number 77960-SNA-H821-M1

What does the airbag control unit 77960-SNA-H821-M1 do?

As the central control unit of the restraint system (SRS) of Honda, the airbag control unit 77960-SNA-H821-M1 evaluates the sensors. In an accident it decides within milliseconds which airbags and seatbelt pretensioners trigger. It monitors the system without interruption, and faults appear via the airbag warning light.

The sensors and trigger circuits report their values to this unit, which then acts. In this way the system reacts without delay in an emergency.

After an accident the unit stores crash data and locks itself.

Why does the control unit 77960-SNA-H821-M1 fail?

The most common cause is stored crash data after an accident, even if no airbag has deployed. A normal reading device cannot remove this data. Other causes are aged components, cold solder joints, moisture at plugs and voltage spikes.

The further causes in detail:

• Aged electronic components
• Cold solder joints
• Moisture and corrosion on plug connections
• Voltage spikes, for example from a jump start or a weak battery

The examination of the unit shows which of these points applies.

How can you tell that the 77960-SNA-H821-M1 is defective?

A defect on this control unit shows through the airbag warning light, which stays on permanently or intermittently. This is accompanied by a fault message in the instrument cluster, a diagnostic tool without a connection and a fault memory that cannot be cleared.

These signs are typical:

• Airbag warning light in the instrument cluster stays on
• Fault message in the instrument cluster
• No connection between diagnostic tool and control unit
• Fault memory persists

In an emergency, airbags and seatbelt pretensioners may not trigger. The light is therefore a clear reason to have the system checked.

Which vehicles is the 77960-SNA-H821-M1 fitted in?

The control unit 77960-SNA-H821-M1 is fitted in these vehicles: Honda Civic 8th generation (2005-2011). The part number on the unit remains decisive.

The overview shows the vehicles assigned to this part number:

• Honda Civic 8th generation (2005-2011)

Compare the part number on the label of the removed unit with this page; that confirms the match of the unit. Also have the fault memory read out beforehand. Only this result shows whether the control unit is defective or whether a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 77960-SMG-G014-M1, 77960-SMG-G021-M1, 77960-SMG-G120-M1, 77960-SNA-L220-M1, 77960-SNA-L230-M1, 77960-SNA-M410-M1.

How does the repair of the 77960-SNA-H821-M1 work?

Your first step is reading out the fault memory with the enclosed log, then disconnect the battery and remove the control unit 77960-SNA-H821-M1. Next, create the repair order online and pack the control unit before sending it in. Processing at Airbag24 usually takes 3–4 working days.

Airbag24 examines the unit on the test bench, repairs defective components and carries out a function test. Stored crash data is erased in the process. Your own unit then comes back to you.

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-SNA-H821-M1 get to Airbag24?

You either send the control unit 77960-SNA-H821-M1 yourself as a parcel, or you arrange a UPS collection for an extra charge. After the repair, Airbag24 sends it back to you by UPS.

Enclose the printed repair order and pack the unit shock-proof.