Airbag control unit with part number 77960-TWB-H230-M4

What does the airbag control unit 77960-TWB-H230-M4 do?

The airbag control unit 77960-TWB-H230-M4 forms the control centre of the restraint system (SRS) in Honda. It evaluates the crash sensors, decides on triggering airbags and seatbelt pretensioners within milliseconds in an emergency, and monitors the system continuously. After an accident, it stores crash data and locks itself.

While driving, the unit continuously checks its connections and the sensor signals. If it detects a deviation, it indicates this via the airbag warning light.

The lock affects only the control unit. Anyone reading the part number 77960-TWB-H230-M4 on the unit has in hand the unit that decides on triggering and warning.

Why does the control unit 77960-TWB-H230-M4 fail?

Most common cause: crash data stored after an accident, even without an airbag triggering, which a conventional diagnostic tool cannot remove. Other triggers are ageing electronics, dry solder joints, moisture and corrosion on plug connections, and voltage spikes. Airbag24 deletes the crash data during the repair.

Crash data arises as soon as the unit classifies an event as an accident. Whether an airbag triggers is irrelevant to the storage, so the problem can also occur after an apparently harmless incident.

A further group of causes concerns the hardware: ageing electronic components and dry solder joints can cause contact problems over time.

Another group concerns the environment and the power supply. Moisture and corrosion on plug connections, as well as voltage spikes, for example from a weak battery or a jump start, belong to this group.

How can you tell that the 77960-TWB-H230-M4 is defective?

A defect shows up as an airbag warning light that lights up permanently or intermittently, as fault messages in the instrument cluster, as a diagnostic tool that receives no contact from the control unit, and as a fault memory that cannot be cleared. Airbags and seatbelt pretensioners may then fail to trigger in an emergency.

The individual signs at a glance:

• airbag warning light lights up permanently or intermittently
• fault message in the instrument cluster
• diagnostic tool receives no connection to the control unit
• fault memory cannot be cleared

Anyone who notices one of these has the system checked promptly and notes the display in the instrument cluster.

Which vehicles is the 77960-TWB-H230-M4 fitted in?

The 77960-TWB-H230-M4 is fitted in these vehicles: Honda Accord 10th generation (2017-2024). The part number on the unit is unambiguous, not the vehicle designation.

Here follows the list of vehicles we have for this part number.

• Honda Accord 10th generation (2017-2024)

A couple of checks make sense before removal. First compare the number on the label of the unit with this page; that only confirms that you have the right part. Then have the fault memory read, because 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-T3L-A012-M1, 77960-T3L-C012-M4, 77960-T3L-C020-M4, 77960-T3L-C030-M4, 77960-T3L-F012-M4, 77960-T3L-F020-M4.

How does the repair of the 77960-TWB-H230-M4 work?

Start by having the fault memory read out and attaching the log. Then disconnect the battery and remove the control unit. Create a repair order online and send the unit in, well packed. Processing at Airbag24 usually takes 3–4 working days.

The sequence is prescribed for safety reasons when working on the vehicle.

At Airbag24, the unit first goes onto the test bench. Defective components are repaired, stored crash data is deleted and a function test is carried out before your own unit begins its return journey.

The 3–4 working days apply only to checking, repairing and testing at Airbag24, not to your steps or to shipping.

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-TWB-H230-M4 get to Airbag24?

The route to Airbag24 is by parcel: either you ship it yourself or you arrange a UPS collection for an extra charge. The return also goes by UPS, once the repair is complete.

Pack the printed repair order into the parcel and make sure the packaging is shock-resistant.