Airbag control unit with part number 89170-78040

What does the airbag control unit 89170-78040 do?

For Lexus, the airbag control unit 89170-78040 takes over control of the restraint system (SRS). From the signals of the crash sensors, it calculates within milliseconds which airbags and seatbelt pretensioners fire. It also checks the system constantly and shows faults via the airbag warning light.

After an accident, it creates crash data and locks itself.

In everyday use this function goes unnoticed. Only a fault makes it visible.

Why does the control unit 89170-78040 fail?

The most common cause with the 89170-78040 is crash data from an accident that cannot be erased with a normal diagnostic tool, even if no airbag fired. Further causes are aged components, solder joints, moisture and voltage spikes.

Airbag24 removes the crash data during the repair. The other causes arise from ageing, moisture and the voltage in the vehicle electrical system.

• ageing of electronic components
• cold solder joints
• corrosion at plug connections caused by moisture
• voltage spikes, for example with a weak battery or jump-starting

The exact cause can only be found on the unit itself.

How can you tell that the 89170-78040 is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently, and an error message appears in the instrument cluster at the same time. If no connection to the diagnostic tool is established, or the fault memory stays unchanged, this points to a fault in the 89170-78040.

A fault memory that cannot be cleared also counts among the signs. In an emergency, airbags and seatbelt pretensioners may then not be able to deploy.

If the display shows a problem, have it checked promptly.

Which vehicles is the 89170-78040 fitted in?

The 89170-78040 is fitted in these vehicles: Lexus NX AZ10 (2014-2017) and AZ10 Facelift (2017-2021).

Below you will find the list of vehicles for this part number.

• Lexus NX AZ10 (2014-2017)
• Lexus NX AZ10 Facelift (2017-2021)

Comparing the part number on the label of the removed unit with this page is a safeguard that you have the right unit. Whether the control unit itself is defective, or whether a plug or cable is the problem, is shown only by the fault memory read out. Have this read out before removal.

For the same vehicles, we also repair control units with the part numbers 89170-78010.

How does the repair of the 89170-78040 work?

The fault memory is read out first, and you attach the log. After disconnecting the battery, the control unit 89170-78040 is removed; then you create the repair order online and send the unit in well packed. Airbag24 needs 3–4 working days for inspecting, repairing and testing.

There, the defective components are repaired, the crash data is erased and a function test is carried out. Afterwards your own unit goes back 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 89170-78040 get to Airbag24?

You send the unit as a parcel, or have it collected by UPS for an extra charge. After the repair, Airbag24 sends your own unit back by UPS. The printed repair order for the 89170-78040 belongs in the parcel, as does shock-proof packaging.

Make sure the unit sits firmly in the box and nothing shifts.