Airbag control unit with part number 77960-TM8-J411-M2

What does the airbag control unit 77960-TM8-J411-M2 do?

The control unit 77960-TM8-J411-M2 is the central control unit of the restraint system (SRS) in vehicles from Honda. It evaluates the signals from the crash sensors and, in a crash, decides within milliseconds which airbags and seatbelt pretensioners are triggered. After a crash it stores crash data and locks itself.

During operation the unit monitors the entire system. If it detects a fault, it shows this via the airbag warning light in the instrument cluster.

Because the control must react quickly in an emergency, it counts as a safety-relevant component of the vehicle. A fault therefore affects not just a display but the protective effect of the entire system.

Why does the control unit 77960-TM8-J411-M2 fail?

The most common cause is crash data stored after an accident, even if no airbag has deployed; it cannot be erased with a normal diagnostic tool. Other possible causes are aged electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes.

Crash data arises in an accident, even if no airbags are triggered. It therefore also appears in vehicles whose airbags did not deploy.

The other causes lie in the electronics themselves or in their surroundings. Components age, solder joints can go cold, and moisture attacks the contacts. Voltage spikes arise, for example, with a weak battery or when starting with external power.

How can you tell that the 77960-TM8-J411-M2 is defective?

The airbag warning light lights up permanently or intermittently, and an error message appears in the instrument cluster. The diagnostic tool finds no connection to the control unit, or the fault memory cannot be cleared. In an emergency, the airbags and seatbelt pretensioners may then fail to deploy.

The warning light is the most important sign because it reports the fault directly. A brief illumination when the ignition is switched on is part of the normal self-test; if the light stays on afterwards, a fault has been reported.

If the warning light stays on permanently, have the fault memory read out promptly. Even without a visible error message, a fault memory that cannot be emptied may indicate a problem.

Which vehicles is the 77960-TM8-J411-M2 fitted in?

The control unit 77960-TM8-J411-M2 is fitted in these vehicles: Honda Insight 2nd generation (2009-2014).

The overview lists individually the vehicles to which this part number belongs.

• Honda Insight 2nd generation (2009-2014)

Compare the part number on the label of the removed unit with this page; this only ensures that it is the correct unit. The comparison does not clarify the cause. Therefore have the fault memory read out beforehand, because only the report shows whether the control unit is defective or a connector or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 77960-TM8-A01, 77960-TM8-A020-M2, 77960-TM8-A03.

How does the repair of the 77960-TM8-J411-M2 work?

Have the fault memory read out first and attach the report; then disconnect the battery and only then remove the control unit. Next create the repair order online and send in the well-packed unit. At Airbag24, inspection, repair and function test usually take 3–4 working days.

Airbag24 checks the unit on the test bench, replaces defective components and erases stored crash data. A function test follows, and then your own repaired unit is returned to you.

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-TM8-J411-M2 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 protect the control unit with shockproof packaging.