Airbag control unit with part number 77960-TMM-F040-M4

What does the airbag control unit 77960-TMM-F040-M4 do?

The SRS control unit 77960-TMM-F040-M4 forms the central evaluation unit of the restraint system for Honda. Based on the crash sensors, it decides when airbags and seatbelt pretensioners are triggered and monitors the system continuously. After an accident it stores crash data and locks itself.

It shows irregularities via the airbag warning light in the instrument cluster, so that you are warned.

Why does the control unit 77960-TMM-F040-M4 fail?

The most common cause is stored crash data after an accident, even without a triggered airbag. Older components, cold solder joints, moisture on connectors and voltage spikes also contribute, for example from a weak battery or jump-starting.

Stored crash data remain as an entry in the unit. A normal diagnostic tool cannot remove them, which is why the fault continues to be displayed.

The other causes are closely linked to the electronics. Solder joints can go cold, and plug connections suffer from moisture and corrosion.

Voltage spikes also belong to this group, for example from a weak battery or a jump-start.

How can you tell that the 77960-TMM-F040-M4 is defective?

A defect in the 77960-TMM-F040-M4 can be recognised by the airbag warning light in the instrument cluster, which lights up permanently or intermittently. Typical signs also include a fault message in the instrument cluster, no connection to the diagnostic tool and a fault memory that cannot be cleared.

If there is a defect, airbags and seatbelt pretensioners may not deploy in an emergency. If the light comes on, please have the system checked promptly.

Which vehicles is the 77960-TMM-F040-M4 fitted in?

The control unit 77960-TMM-F040-M4 is found in the following model: Honda CR-V 5 (2018-2023).

The assignment to this part number is as follows:

• Honda CR-V 5 (2018-2023)

Comparing the label of the removed unit with this page ensures that it is the correct control unit. Whether it is defective itself or a connector or cable is behind the fault is shown only by the fault memory, which you have read out beforehand.

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-TMM-F040-M4 work?

You read out the fault memory beforehand, and the log goes into the package afterwards. Then you disconnect the battery and only then remove the control unit 77960-TMM-F040-M4. Afterwards you create a repair order online and send in the well-packed unit.

At the Airbag24 workshop the unit is examined on the test bench. Defective components are replaced, stored crash data erased and a functional test carried out. Then you receive your own unit back. Processing at Airbag24 usually takes 3–4 working days; this time covers examining, repairing and testing only.

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-TMM-F040-M4 get to Airbag24?

You send the control unit 77960-TMM-F040-M4 as a parcel, or have it collected by UPS for an extra charge. Airbag24 sends the repaired unit back by UPS as well.

The printed repair order goes in the package, and you pack the unit shock-proof.