Airbag control unit with part number 77960-T1G-R920-M4

What does the airbag control unit 77960-T1G-R920-M4 do?

The airbag control unit 77960-T1G-R920-M4 is the central control unit of the restraint system (SRS) of Honda. It evaluates the signals from the crash sensors, decides in a collision within fractions of a second which airbags and seatbelt pretensioners are triggered, and monitors the system continuously. It reports faults via the airbag warning light.

In normal driving, the unit works unobtrusively in the background and constantly checks whether all connected components respond. These include the sensors, the seatbelt pretensioners and the airbags themselves. If it detects a deviation, it stores it in the fault memory.

After an accident, the control unit stores crash data and locks itself. The lock is only lifted by the repair. The next section explains which data this is and why it can be the cause of a failure.

Why does the control unit 77960-T1G-R920-M4 fail?

The most common cause is crash data stored after an accident, even if no airbag has deployed; a normal diagnostic tool cannot erase it. Other causes include aged electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes, for example from a weak battery or a jump start.

Crash data is created as soon as the unit registers an impact. It remains in the memory even if no airbag has been triggered, and it cannot be removed with a normal diagnostic tool.

Independently of this, the electronic components age over time. Solder joints on the circuit board can go cold and lose contact, and moisture or corrosion at the plug connections disturbs signal transmission.

Voltage spikes also stress the unit, for example when the battery is weak or when a jump start is made from another vehicle.

How can you tell that the 77960-T1G-R920-M4 is defective?

Typical signs are the airbag warning light in the instrument cluster, which stays on permanently or intermittently, an error message in the instrument cluster, a diagnostic tool without connection to the control unit, and a fault memory that cannot be cleared. In this case, airbags and seatbelt pretensioners may not deploy in an emergency.

Pay particular attention to the warning light, because it reports every detected fault in the restraint system. The following points help you classify the situation:

• Airbag warning light stays on permanently or intermittently
• Error message in the instrument cluster
• Diagnostic tool cannot find the control unit
• Fault memory cannot be cleared

If such signs appear, have the system checked promptly.

Which vehicles is the 77960-T1G-R920-M4 fitted in?

The airbag control unit 77960-T1G-R920-M4 is fitted in these vehicles: Honda CR-V 4 RM (2012-2018).

You will find the vehicles to which this part number is assigned here:

• Honda CR-V 4 RM (2012-2018)

Compare the part number on the label of the removed unit with this page; this only confirms that it is the right unit. Whether the control unit itself is defective or a plug or cable is the cause only becomes clear from the fault memory, which must be read out beforehand. Have it read out before removal.

For the same vehicles, we also repair control units with the part numbers 5WK43782, 77960-SWA-G212-M4, 77960-SWA-G214-M4, 77960-T1G-G920-M4.

How does the repair of the 77960-T1G-R920-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 in the unit well packed. At Airbag24, processing usually takes 3–4 working days.

At Airbag24, the unit is first examined on the test bench. Defective components are repaired, stored crash data is erased, and a function test checks the result. Afterwards the unit goes back to you.

The order is important for safety: the control unit may only be removed after the battery has been disconnected, and the enclosed log belongs to the order.

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-T1G-R920-M4 get to Airbag24?

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

Place the printed repair order in the parcel and pack the unit shock-proof before handing it over.