Airbag control unit with part number 77960-TEA-B020-M4

What does the airbag control unit 77960-TEA-B020-M4 do?

The airbag control unit 77960-TEA-B020-M4 controls the restraint system (SRS) of Honda. From the signals of the crash sensors it determines within milliseconds whether an accident requires deployment, and then decides which airbags and seatbelt pretensioners fire.

During operation the unit continuously checks all connected components. If it detects a fault, the airbag warning light in the instrument cluster lights up, and the message stays visible until the fault has been rectified.

If the vehicle has been involved in an accident, the control unit stores crash data and then locks itself. This lock only ends with a repair in which the data is removed.

Why does the control unit 77960-TEA-B020-M4 fail?

The most common cause is crash data that remains in the memory after an accident, even if no airbag has deployed. A normal diagnostic tool cannot reach this data. In addition there are ageing components, corrosion on plugs, cold solder joints and voltage spikes, for example from a weak battery or from jump-starting.

Whether or not an airbag has deployed makes no difference to the stored data. The data stays in the unit until it is specifically removed, which is why a reset with an ordinary tool may have no effect.

The other causes mainly concern the electronics themselves. Ageing components, damp plug connections and voltage spikes in the vehicle electrical system can trigger faults that have nothing to do with the accident.

How can you tell that the 77960-TEA-B020-M4 is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently, an error message appears in the instrument cluster, the diagnostic tool gets no connection to the control unit, and the fault memory cannot be cleared. In an emergency, airbags and seatbelt pretensioners may possibly not deploy.

The warning light does not come on only for a major problem, but already for a minor fault in the wiring harness. Do not therefore wait until it can no longer be overlooked.

Look into the warning as soon as it stays on after the ignition is switched on. A check of the system will establish whether the control unit or the wiring is affected.

Which vehicles is the 77960-TEA-B020-M4 fitted in?

The control unit 77960-TEA-B020-M4 is fitted in this vehicle: Honda Civic 10th generation (2015-2022).

You can see the matching assignment to the models in this overview:

• Honda Civic 10th generation (2015-2022)

Check the label on the removed unit and compare the part number with this page. This only confirms that it is the right unit. Have the fault memory read out beforehand, because the log 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-TBA-A01, 77960-TBA-A02, 77960-TBA-A03, 77960-TBA-A04, 77960-TBA-A05.

How does the repair of the 77960-TEA-B020-M4 work?

First have the fault memory read out and attach the log to the unit. Then disconnect the battery, and only then remove the control unit. Next create a repair order online and send the unit in well packed.

Airbag24 takes the unit onto the test bench and examines it. Defective components are repaired or replaced, the stored crash data is removed, and a functional test completes the work.

The unit is then returned to you. Processing at Airbag24 usually takes 3–4 working days, and this time refers solely to checking, repair and functional 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-TEA-B020-M4 get to Airbag24?

You send the unit as a parcel or book a UPS collection for an extra charge. After the repair Airbag24 sends the unit back to you by UPS.

Put the printed repair order in the parcel. Pack the control unit shock-resistant so that it is protected in transit.