Airbag control unit with part number 89170-78080

What does the airbag control unit 89170-78080 do?

The airbag control unit 89170-78080 controls the restraint system (SRS) on Lexus. It reads the crash sensors, determines in the event of an accident within milliseconds which airbags and seatbelt pretensioners to trigger, and monitors the system continuously. It shows faults via the airbag warning light.

Monitoring covers the connections to all involved components. Irregularities are stored in the fault memory, where they can be read out.

After an accident the unit stores crash data and locks itself. Evaluation and diagnosis therefore run through this one control unit.

Why does the control unit 89170-78080 fail?

The most common cause is crash data from an accident, even if no airbag was triggered; a normal diagnostic tool cannot delete it. Other causes include aged components, cold solder joints, moisture and corrosion at plug connectors, and voltage spikes.

Crash data remains in the unit after an accident, even if no airbag fired. A normal diagnostic tool does not remove these entries, so the fault stays visible.

Aged electronics, cold solder joints and moisture at the plug connections also count among the causes. Voltage spikes from a weak battery or jump-starting put additional strain on the circuits.

How can you tell that the 89170-78080 is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently, a fault message appears in the instrument cluster, and the diagnostic tool has no connection to the control unit. A fault memory that cannot be cleared also indicates a defect. In a real emergency, airbags and seatbelt pretensioners may then fail to trigger.

The warning light is the most important sign, because it shows the fault as soon as the system detects it. Whether it lights permanently or only intermittently does not matter for the decision on testing.

Have the finding checked promptly before you continue driving the car.

Which vehicles is the 89170-78080 fitted in?

The airbag control unit 89170-78080 is fitted in these vehicles: Lexus NX AZ10 (2014-2017) and AZ10 Facelift (2017-2021). This information lets you match the unit to the car.

The following vehicles are on record for this part number:

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

Before removal there are two steps. First, compare the part number on the label of the unit with this page; this ensures you have the right unit. Second, have the fault memory read out, because only this result shows whether the control unit is defective or a plug or a 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 89170-78080 work?

First have the fault memory read out and enclose the log. Then disconnect the battery and only then remove the control unit. Next, create a repair order online and send the unit in well packed. At Airbag24, testing, repair and functional testing usually take 3–4 working days.

Airbag24 checks the unit on the test bench and repairs defective components. Stored crash data is deleted during this process, followed by a functional test.

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 89170-78080 get to Airbag24?

You send the control unit 89170-78080 as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 sends the unit back to you by UPS.

Put the printed repair order in the parcel and pack the unit shock-resistant.