Airbag control unit with part number 77960-TMC-Q040-M4

What does the airbag control unit 77960-TMC-Q040-M4 do?

The unit is the central control unit of the SRS system of Honda. It processes the readings from the crash sensors and decides within milliseconds in an accident which airbags and seatbelt pretensioners deploy. After an accident it stores crash data and locks itself.

In addition, the control unit checks the entire restraint system continuously, even during normal driving.

If a fault is detected, the control unit switches on the airbag warning light in the instrument cluster.

Why does the control unit 77960-TMC-Q040-M4 fail?

The most common cause is crash data stored after an accident, even if no airbag has deployed. Further causes include aged electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes. Airbag24 erases the crash data during the repair of control unit 77960-TMC-Q040-M4.

The other causes at a glance:

• Aged electronic components
• Cold solder joints on the circuit boards
• Moisture and corrosion at plug connections
• Voltage spikes, for example from a weak battery or a jump start

A normal diagnostic tool cannot erase crash data, and this applies regardless of the rest of the unit's condition.

How can you tell that the 77960-TMC-Q040-M4 is defective?

You recognise a defect in control unit 77960-TMC-Q040-M4 by the airbag warning light in the instrument cluster, which stays on permanently or intermittently. Error messages may accompany it, and the fault memory cannot be cleared.

The signs in detail:

• The airbag warning light stays on permanently.
• The light comes on only intermittently.
• An error message appears in the instrument cluster.
• The diagnostic tool finds no connection to the control unit.
• The fault memory cannot be cleared.

In these cases, airbags and seatbelt pretensioners may fail to deploy in an emergency. Do not rely on the vehicle driving normally.

Which vehicles is the 77960-TMC-Q040-M4 fitted in?

The 77960-TMC-Q040-M4 is fitted in these Honda vehicles: Honda CR-V 5 (2018-2023). The assignment is based on the data we hold for this part number.

Here are the vehicles on record for this part number:

• Honda CR-V 5 (2018-2023)

First check whether the part number on the label of your removed unit matches this page. That only clarifies whether it is the right unit. Whether the control unit is defective, or whether a plug or cable is the cause, is shown by the fault memory once it has been read out.

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-Q040-M4 work?

First have the fault memory read out and enclose the log with the unit. Then disconnect the battery and only afterwards remove the control unit. Processing at Airbag24 takes 3–4 working days, counted only for inspecting, repairing and testing.

Then create a repair order online and send the well-packed unit.

At Airbag24 the unit is inspected on the test bench, defective components are replaced, stored crash data is erased and a function test is run. Only then does your own unit go back.

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-Q040-M4 get to Airbag24?

Either you send the control unit 77960-TMC-Q040-M4 in as a parcel, or you book a UPS collection for an extra charge. After the repair, UPS brings the unit back to you.

A printed repair order belongs in the parcel, and the unit is packed shockproof.