Airbag control unit with part number 89170-33P90

What does the airbag control unit 89170-33P90 do?

The airbag control unit 89170-33P90 is the central control unit of the SRS restraint system for Lexus. In an impact it evaluates the crash sensors and determines within milliseconds which airbags and seatbelt pretensioners are triggered.

The unit checks the function of the system continuously. If it detects a fault, it is shown via the airbag warning light in the instrument cluster.

After an accident the control unit secures the crash data and locks itself. The lock is lifted only by a repair.

Why does the control unit 89170-33P90 fail?

On the 89170-33P90, the most common cause is stored crash data from an accident, even when no airbag has triggered. A normal diagnostic tool cannot remove this data. Other causes are aged electronics, cold solder joints, moisture and corrosion on connectors, and voltage spikes.

The crash data remains until it is erased during the repair. Until then, it does not prevent any other check.

The other causes concern the electronics themselves. Components age over time, solder joints can become defective, and moisture with corrosion impairs the contacts. Voltage spikes, for example from a weak battery or when connecting a jump-start, put additional strain on the circuit.

How can you tell that the 89170-33P90 is defective?

A defect on the 89170-33P90 shows itself through the airbag warning light, which lights up permanently or intermittently, through a fault message in the instrument cluster, through a missing connection to the diagnostic tool, and through a fault memory that cannot be cleared. In an emergency, airbags and seatbelt pretensioners may then possibly not trigger.

The warning light is the most important warning sign, because it tells the driver without any further action that the system has detected a fault. If it stays lit permanently, a check is advisable.

A missing connection to the diagnostic tool can also be due to lines or plugs. Only the fault memory shows where the cause lies.

Which vehicles is the 89170-33P90 fitted in?

The 89170-33P90 is fitted in these vehicles: Lexus ES AXZH60 (from 2018).

The following list shows the vehicles recorded for this part number.

• Lexus ES AXZH60 (from 2018)

Compare the part number on the label of the removed unit with this page. This only establishes that it is the right unit. Before you remove the control unit, have the fault memory read out as well, because only this result shows whether the unit is defective or a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 89170-06590, 89170-06880.

How does the repair of the 89170-33P90 work?

Processing at Airbag24 takes 3–4 working days as a rule, during which the 89170-33P90 is tested, repaired and checked. Before that, you have the fault memory read out, disconnect the battery and remove the unit, before you create a repair order online and send it in.

The order of the steps serves safety, because the restraint system must not be activated unintentionally during the work.

In-house, the unit is first examined, defective components are repaired or replaced, the stored crash data is erased, and finally a function test is carried out.

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 89170-33P90 get to Airbag24?

You send the 89170-33P90 as a parcel or book a UPS collection for an extra charge. Returns after the repair are made by UPS.

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