Airbag control unit with part number 89170-78380

What does the airbag control unit 89170-78380 do?

The airbag control unit 89170-78380 coordinates the restraint system (SRS) in Lexus vehicles. It evaluates the signals from the crash sensors and decides within milliseconds in a collision which airbags and seatbelt pretensioners are triggered. After an accident it stores crash data and locks itself.

The unit monitors the system continuously and reports faults via the airbag warning light in the instrument cluster.

The decision is made by the electronics without any action on your part, because in a crash there is no time for intervention.

Why does the control unit 89170-78380 fail?

The most common cause on the 89170-78380 is a fault pattern caused by stored crash data, even if no airbag has deployed. Other causes include aged components, cold solder joints, moisture at plug connectors, corrosion and voltage spikes.

A normal diagnostic tool cannot erase crash data. They therefore remain in the control unit until they are removed during a repair.

The other causes relate to age, environment and power supply. Components age, solder joints can go cold, moisture and corrosion damage plug connectors, and voltage spikes arise, for example, from a weak battery or a jump start.

How can you tell that the 89170-78380 is defective?

The airbag warning light in the instrument cluster lights up on the 89170-78380 permanently or intermittently. This indicates a fault, and further signs may appear:

• Fault message in the instrument cluster
• Diagnostic tool has no connection to the control unit
• Fault memory cannot be cleared

With these signs, airbags and seatbelt pretensioners may possibly not deploy in an emergency.

Precisely because the vehicle indicates the fault itself, it is worth clarifying it promptly.

Which vehicles is the 89170-78380 fitted in?

The 89170-78380 is fitted in these vehicles: Lexus NX AZ20 (from 2021). To check whether your car is among them, look at the list and the label on the removed unit.

The models at a glance:

• Lexus NX AZ20 (from 2021)

First, compare the number on the label with this page so that the correct unit is confirmed. Second, have the fault memory read out beforehand, because only this result separates a defective control unit from a plug or cable problem.

For the same vehicles, we also repair control units with the part numbers 89170-F6010.

How does the repair of the 89170-78380 work?

On the 89170-78380, first retrieve the fault memory and enclose the log. Then disconnect the battery and only then remove the control unit. Next, create the repair order online and send the unit in well packed.

At Airbag24 the unit is checked on the test bench, followed by the repair of defective components, the erasure of stored crash data and a function test.

Airbag24 usually allows 3–4 working days for checking, repairing and testing.

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 89170-78380 get to Airbag24?

You send the control unit 89170-78380 as a parcel to Airbag24 or book a UPS collection for an extra charge. Airbag24 sends the unit back by UPS after the repair.

Packed shock-proof, with the printed repair order in the parcel, the unit is on its way.