Airbag control unit with part number 77960-TMC-U030-M4

What does the airbag control unit 77960-TMC-U030-M4 do?

The airbag control unit 77960-TMC-U030-M4 acts as the central control unit for the restraint system (SRS) for Honda. It evaluates the crash sensors, decides in an emergency within milliseconds whether airbags and seatbelt pretensioners are triggered, and monitors the system continuously. Faults are indicated via the airbag warning light.

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

While driving, it continuously checks its connections and the connected components. Anomalies are logged in the fault memory and shown in the instrument cluster.

Why does the control unit 77960-TMC-U030-M4 fail?

The most common cause is stored crash data after an accident, even if no airbag has deployed, and a normal diagnostic tool cannot erase it. Other causes are aged electronic components, cold solder joints, moisture and corrosion at plug connectors, and voltage spikes.

Stored crash data are entries in the memory of the control unit that remain even when the vehicle looks undamaged on the outside. The other causes concern the electronics themselves or their environment in the vehicle. Moisture acts mainly on plug connectors; voltage spikes arise, for example, from a weak battery or a jump start.

How can you tell that the 77960-TMC-U030-M4 is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently as soon as the control unit detects a fault. In addition there may be a fault message in the instrument cluster, no connection between the diagnostic tool and the control unit, and a fault memory that cannot be erased.

The airbag warning light is the most important warning sign, because it is in view in everyday driving. If it lights up, do not wait for the problem to resolve itself.

As long as the fault exists, airbags and seatbelt pretensioners may not trigger in an emergency. A defect in the control unit should therefore be investigated promptly.

Which vehicles is the 77960-TMC-U030-M4 fitted in?

The control unit 77960-TMC-U030-M4 is fitted in these vehicles: Honda CR-V 5 (2018-2023).

The assignment to the individual models is shown in this overview.

• Honda CR-V 5 (2018-2023)

Compare the part number on the label of the removed unit with this page. This only confirms that it is the correct unit. Have the fault memory read out beforehand, because only that 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-TLA-A240-M4, 77960-TLA-A250-M4, 77960-TLA-A310-M4, 77960-TLA-A320-M4, 77960-TLA-A410-M4, 77960-TLA-A420-M4.

How does the repair of the 77960-TMC-U030-M4 work?

First have the fault memory read out and attach the log. Then disconnect the battery and only then remove the control unit. Next, create a repair order online and send the unit in well packed. Processing at Airbag24 usually takes 3–4 working days.

Airbag24 checks the unit on the test bench, repairs defective components, erases the stored crash data and carries out a function test. The unit then goes 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-TMC-U030-M4 get to Airbag24?

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

Put the printed repair order in the parcel and pack the control unit shock-proof.