Airbag control unit with part number 89170-76340

What does the airbag control unit 89170-76340 do?

The airbag control unit 89170-76340 coordinates the restraint system (SRS) of Lexus and controls which airbags and seatbelt pretensioners fire in an accident. To do this, it evaluates the signals from the crash sensors.

The unit monitors the system continuously and shows faults via the airbag warning light.

After an accident, it stores crash data and locks itself. This behaviour is important for understanding a defect.

Why does the control unit 89170-76340 fail?

The most common cause is crash data stored after an accident, even if no airbag has deployed. In addition come ageing electronics, cold solder joints, moisture and corrosion on plug connections, and voltage spikes.

Crash data cannot be erased with a normal diagnostic tool.

Electronic components can lose reliability over time, solder joints become cold, and moisture in the plugs causes corrosion. Voltage spikes, for example from a weak battery or a jump start, put additional strain on the unit.

How can you tell that the 89170-76340 is defective?

The airbag warning light in the instrument cluster stays on permanently or intermittently. This comes with a fault message in the instrument cluster, a lack of connection to the diagnostic tool and a fault memory that cannot be cleared.

The signs at a glance:

• Airbag warning light on permanently or intermittently
• Fault message in the instrument cluster
• Diagnostic tool gets no connection to the control unit
• Fault memory cannot be cleared

Airbags and seatbelt pretensioners may then not deploy in an emergency. This has to be taken seriously.

Which vehicles is the 89170-76340 fitted in?

The control unit 89170-76340 is fitted in these vehicles: Lexus UX MZAA10 (from 2018). The information relates to the make Lexus and this part number.

Here is the vehicle list:

• Lexus UX MZAA10 (from 2018)

Comparing the part number on the label with this page confirms that you have the correct unit, nothing more. Having the fault memory read out beforehand gives clarity: only this result shows whether the control unit is defective or whether a plug or cable is the cause.

How does the repair of the 89170-76340 work?

First read out the fault memory and attach the log, then disconnect the battery and remove the control unit. Create the repair order online, then send the unit off well packed. Airbag24 checks it on the test bench, replaces defective components, erases crash data and carries out a function test; processing takes 3–4 working days.

The unit is returned to you after the function test. The order in which work is done on the vehicle serves safety.

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 89170-76340 get to Airbag24?

You have the choice: the unit goes to Airbag24 as a parcel, or you book a UPS collection for an extra charge. Airbag24 sends the control unit back by UPS after the repair.

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