Airbag control unit with part number 77960-TY3-J320-M4

What does the airbag control unit 77960-TY3-J320-M4 do?

The airbag control unit 77960-TY3-J320-M4 coordinates the restraint system (SRS) in Honda. It processes the crash sensor data, selects the airbags and seatbelt pretensioners that should trigger in an emergency, and checks the system continuously. After an accident it stores crash data and locks itself.

If the unit detects a fault, it indicates this via the airbag warning light in the instrument cluster.

Why does the control unit 77960-TY3-J320-M4 fail?

The most common cause is crash data from an accident, which is found in the unit even if no airbag has deployed; a normal diagnostic tool cannot erase it. Further causes in the 77960-TY3-J320-M4 are ageing electronic components, cold solder joints, moisture at plug connectors and voltage spikes.

• Ageing of the electronic components over their service life
• Cold solder joints that can interrupt connections
• Moisture and corrosion at plug connectors
• Voltage spikes, for example from a weak battery or a jump start

The list is general, because the individual case cannot be narrowed down without testing. The crash data remains in the memory even if the system then appears to behave normally.

How can you tell that the 77960-TY3-J320-M4 is defective?

The airbag warning light in the instrument cluster lights up constantly or intermittently. A defect in the 77960-TY3-J320-M4 is also indicated by a fault message, a diagnostic tool without a connection, or a fault memory that cannot be cleared. This means there is a possibility that airbags and seatbelt pretensioners will not deploy in an emergency.

The warning light is not merely a small lamp; it indicates a fault that the system itself has detected.

A missing connection to the diagnostic tool may be due to the control unit, but equally to a wire or a connector.

Which vehicles is the 77960-TY3-J320-M4 fitted in?

The control unit 77960-TY3-J320-M4 is fitted in the following vehicles: Honda Legend 5th generation (2014-2021).

The vehicle list below shows the vehicles for this number:

• Honda Legend 5th generation (2014-2021)

Compare the part number on the label of the removed unit with this page. This only confirms that it is the correct unit. Beforehand the fault memory should have been read out, because only this log shows whether the control unit is defective or whether a connector or cable is the cause.

How does the repair of the 77960-TY3-J320-M4 work?

On the 77960-TY3-J320-M4 have the fault memory read out first and attach the log to the unit. Then disconnect the battery, remove the control unit and create the repair order online. At Airbag24 processing usually takes 3–4 working days.

On the test bench Airbag24 examines the unit, rectifies defective components, removes the stored crash data and tests the function. The 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-TY3-J320-M4 get to Airbag24?

You can send the control unit 77960-TY3-J320-M4 as a parcel, or book a UPS collection for an extra charge. Airbag24 returns it to you by UPS after the repair.

The repair order goes into the parcel printed out, and the unit is packed shock-proof.