Airbag control unit with part number 77960-T2A-Z921-M1

What does the airbag control unit 77960-T2A-Z921-M1 do?

In vehicles from Honda, the airbag control unit 77960-T2A-Z921-M1 directs the restraint system (SRS). It checks the messages from the crash sensors, decides on triggering in an accident and monitors the system constantly. It shows faults via the airbag warning light.

The monitoring ensures that faults become visible. Without a functioning control, the entire system would have no reliable basis.

After an accident it stores crash data and locks itself.

Why does the control unit 77960-T2A-Z921-M1 fail?

Crash data from an earlier accident is the most common cause, even if no airbag has triggered. It cannot be deleted with a standard diagnostic tool. Other causes are aged components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes.

The crash data is held in the unit's memory. Aged components, cold solder joints and moisture at plug connections can, however, affect the unit regardless of an accident.

Voltage spikes arise, for example, from a weak battery or jump-starting. Which of these causes is actually present only the inspection will show.

How can you tell that the 77960-T2A-Z921-M1 is defective?

A defect in the 77960-T2A-Z921-M1 shows up mainly on the airbag warning light in the instrument cluster and in error messages. A missing connection to the diagnostic tool or a fault memory that cannot be cleared also points to a problem.

The signs in detail:

• airbag warning light, permanently or intermittently lit
• error message in the instrument cluster
• no connection between diagnostic tool and control unit
• fault memory that cannot be cleared

In an emergency, airbags and seatbelt pretensioners may then possibly not deploy. Such a finding therefore requires a prompt inspection.

Which vehicles is the 77960-T2A-Z921-M1 fitted in?

The control unit 77960-T2A-Z921-M1 is fitted in vehicles from Honda: Honda CR-V 4 RM (2012-2018).

The list shows the vehicles at a glance:

• Honda CR-V 4 RM (2012-2018)

There are two steps to consider beforehand. First compare the part number on the label of the removed unit with this page, as this confirms that you have the correct unit. Then have the fault memory read out, because only that shows whether the control unit is defective or whether a plug or a cable is the cause.

For the same vehicles, we also repair control units with the part numbers 77960-T0A-3070-M4, 77960-T0A-A012-M1, 77960-T0A-A013-M1, 77960-T0A-A210-M1, 77960-T0A-A212-M1, 77960-T0A-A230-M1.

How does the repair of the 77960-T2A-Z921-M1 work?

First have the fault memory read out and enclose the log. Then disconnect the battery and only then remove the control unit. Create the repair order online, and send the well-packed unit in.

Airbag24 tests the unit on the test bench, replaces defective components, deletes stored crash data and carries out a functional test. Your own unit is then returned to you.

Processing at Airbag24 usually takes 3–4 working days. This time applies solely to testing, repairing and checking in the business. 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-T2A-Z921-M1 get to Airbag24?

You send the control unit 77960-T2A-Z921-M1 as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 sends it back to you by UPS.

Enclose the printed repair order, and pack the unit shockproof so that it survives transport.