Airbag control unit with part number 77960-TLA-A420-M4

What does the airbag control unit 77960-TLA-A420-M4 do?

The control unit 77960-TLA-A420-M4 is the central control unit of the SRS in Honda. It processes the readings from the crash sensors and decides in a crash, in fractions of a second, which airbags and seatbelt pretensioners fire.

While driving, the system is monitored throughout in the background. Faults appear via the airbag warning light in the instrument cluster.

After an accident, the unit stores crash data and then locks itself. Only a repair lifts this lock again.

Why does the control unit 77960-TLA-A420-M4 fail?

The most common cause is stored crash data from an accident, even if no airbag has deployed. Standard diagnostic tools cannot remove this data.

Deleting the crash data is part of the repair at Airbag24 and is therefore included.

In addition, aged components play a role in the electronics, as do cold solder joints. Moisture and corrosion at plug connections disrupt the contact, and voltage spikes, such as from a weak battery or a jump start, stress the unit further.

How can you tell that the 77960-TLA-A420-M4 is defective?

A defect can show on the airbag warning light, a fault message in the instrument cluster, or fault memory entries that cannot be cleared.

The airbag warning light in the instrument cluster stays on permanently or flickers intermittently. Messages in the instrument cluster are added to this. If no connection to the diagnostic tool can be established, or the fault memory cannot be emptied, this also points to a defect in the unit.

Airbags and seatbelt pretensioners may then fail to trigger in an emergency. Therefore have the unit checked promptly.

Which vehicles is the 77960-TLA-A420-M4 fitted in?

The control unit 77960-TLA-A420-M4 was fitted in these vehicles: Honda CR-V 5 (2018-2023).

The vehicles listed for this part number in our assignment are shown here:

• Honda CR-V 5 (2018-2023)

Read out the fault memory before you remove the control unit. Only then is it clear whether the unit really is defective or whether a cable or a plug is the cause. Afterwards, compare the part number on the label with this page.

For the same vehicles, we also repair control units with the part numbers 5WK43782, 77960-SWA-G212-M4, 77960-SWA-G214-M4, 77960-SWAA-213-M1.

How does the repair of the 77960-TLA-A420-M4 work?

At Airbag24, checking, repairing and testing the control unit 77960-TLA-A420-M4 usually take 3–4 working days. Before that, you read out the fault memory, remove the control unit and create a repair order online.

Disconnect the battery before removal and enclose the read-out log with the parcel. Then send the packed unit in.

Airbag24 checks the unit on the test bench, replaces defective components, deletes the crash data and carries out a function test. 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-TLA-A420-M4 get to Airbag24?

You send the control unit 77960-TLA-A420-M4 as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 returns it by UPS.

Put the printed repair order into the parcel. Pack the control unit shockproof, so that it arrives undamaged.