Airbag control unit with part number 89170-76640

What does the airbag control unit 89170-76640 do?

The airbag control unit 89170-76640 is the switching centre of the restraint system (SRS) of Lexus. It evaluates the crash sensors, decides in an accident whether airbags and seatbelt pretensioners deploy, and monitors the system continuously.

It shows faults via the airbag warning light in the instrument cluster. After an accident it stores crash data and locks itself.

If this unit fails, the restraint system can no longer work as intended in an emergency.

Why does the control unit 89170-76640 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 are aged components, cold solder joints, moisture and corrosion on plug connections, and voltage spikes.

The unit creates crash data when the sensors classify an impact as relevant. Whether an airbag has deployed cannot be read from this. A diagnostic tool does not remove the data, so the erasure takes place as part of the repair.

Regardless of an accident, aged electronic components, cold solder joints, and moisture and corrosion on plug connections can cause a fault. Voltage spikes from a weak battery or a jump start are also considered as a cause.

How can you tell that the 89170-76640 is defective?

A defect shows itself through an airbag warning light that lights up constantly or intermittently, through a fault message in the instrument cluster, or through a diagnostic tool that finds no contact with the control unit. A fault memory that cannot be cleared also indicates it. In that case, airbags and seatbelt pretensioners may not deploy in an emergency.

The airbag warning light in the instrument cluster is the most important sign. Whether it lights up constantly or only now and then makes no difference to the check.

A fault message in the instrument cluster is also part of the picture. If the connection to the diagnostic tool fails, or the fault memory remains after erasing, the finding is unambiguous.

Have it checked promptly, before the restraint system fails in an emergency.

Which vehicles is the 89170-76640 fitted in?

The control unit 89170-76640 is fitted in these vehicles: Lexus UX MZAA10 (from 2018). Establish whether your vehicle is affected by make and model.

These vehicles are known to us with this part number:

• Lexus UX MZAA10 (from 2018)

Compare the part number on the label of the removed unit with this page. That only confirms that it is the right unit. Then have the fault memory read out, because only this result shows whether the control unit is defective or whether a plug or a cable is the cause.

How does the repair of the 89170-76640 work?

First read out the fault memory and enclose the log, then disconnect the battery and then remove the control unit. Afterwards create a repair order online and send the well-packed unit in. Processing at Airbag24 usually takes 3–4 working days.

The sequence is set for safety reasons. The control unit is removed only after the battery has been disconnected.

Airbag24 examines the unit on the test bench, repairs or replaces defective components, erases stored crash data and carries out a function 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 89170-76640 get to Airbag24?

You send the control unit 89170-76640 as a parcel, or book a UPS collection for an extra charge. After the repair, Airbag24 returns it to you by UPS.

Put the printed repair order into the parcel and pack the unit shockproof.