Airbag control unit with part number 89170-78070

What does the airbag control unit 89170-78070 do?

The airbag control unit 89170-78070 forms the central control unit of the restraint system (SRS) for Lexus. In an accident, it processes the signals from the crash sensors and determines within milliseconds which airbags and seatbelt pretensioners are triggered.

During operation, the unit monitors all components of the system. If it detects a fault, it reports it via the airbag warning light in the instrument cluster.

After an accident, the unit stores crash data and locks itself. The following section explains what lies behind this.

Why does the control unit 89170-78070 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 on plug connections, and voltage spikes.

Stored crash data does not indicate that an airbag has deployed. It stays in the unit until it is erased during repair.

The other causes affect the electronics in everyday use. Aged components and cold solder joints impair function, while moisture, corrosion and voltage spikes, for example from a weak battery or a jump start, load the connections and the electronics.

How can you tell that the 89170-78070 is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently, and a fault message appears in the instrument cluster. In addition, the control unit cannot be reached with the diagnostic tool, or the fault memory cannot be cleared.

The warning light is the most important warning sign. It reports a fault as soon as the system detects one, and whether it stays on permanently or only intermittently does not change the need for a check.

In an emergency, airbags and seatbelt pretensioners may then fail to deploy. Therefore have the system checked promptly.

Which vehicles is the 89170-78070 fitted in?

The control unit 89170-78070 is fitted in these vehicles: Lexus NX AZ10 (2014-2017) and AZ10 Facelift (2017-2021).

The list below shows the vehicles stored for this control unit. It serves for comparison with your own vehicle.

• 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 ensures that you have the right unit in front of you. The fault memory must be read out beforehand, because only this result shows whether the control unit or a connector or cable is the cause.

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

How does the repair of the 89170-78070 work?

First have the fault memory read out and attach the log. Then disconnect the battery and only afterwards remove the control unit. Next, create a repair order online and pack the unit well.

Airbag24 checks the unit on the test bench, repairs defective components, erases crash data and carries out a function test. Processing usually takes 3–4 working days, after which the 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 89170-78070 get to Airbag24?

You send the control unit 89170-78070 to Airbag24 as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 sends it back to you by UPS.

Put the printed repair order into the parcel and pack the unit shock-proof.