Airbag control unit with part number 89170-33B50

What does the airbag control unit 89170-33B50 do?

The airbag control unit 89170-33B50 is the superordinate control unit of the restraint system (SRS) of Lexus. It processes the signals from the crash sensors, decides within milliseconds in a crash whether to trigger the airbags and seatbelt pretensioners, and monitors the system continuously. Faults appear on the airbag warning light.

In an accident the decision has to be made in fractions of a second. To do so, the unit processes the sensor readings without interruption.

After an accident the control unit creates crash data and locks itself.

Why does the control unit 89170-33B50 fail?

The most common cause is crash data from an accident that remain in the unit, even if no airbag has deployed; a standard diagnostic tool cannot erase them. Other triggers are ageing electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes caused by weak batteries or jump starts.

This data is also created in accidents in which no airbags were deployed. Nothing can be seen from the outside.

The other causes develop over a longer period. Solder joints become brittle, moisture attacks contacts, and voltage spikes stress the circuits.

How can you tell that the 89170-33B50 is defective?

The airbag warning light in the instrument cluster lights up permanently or only intermittently, accompanied by a fault message. If no connection to the diagnostic tool can be made or the fault memory persists, this points to a defect. Airbags and seatbelt pretensioners may then not deploy in an emergency.

When the ignition is switched on, the light checks itself. If it does not go out afterwards, have the finding checked.

A fault message additionally confirms the fault, which makes the finding clearer.

Which vehicles is the 89170-33B50 fitted in?

In Lexus vehicles, the control unit 89170-33B50 is fitted in these vehicles: Lexus ES AXZH60 (from 2018). The part number on the label shows whether the removed unit matches this page.

Below you will find the compilation of the vehicles on record.

• Lexus ES AXZH60 (from 2018)

Have the fault memory read out first; the log shows whether the control unit is defective or whether a plug or cable is behind it. The label comparison is additionally recommended, but it does not clarify the cause.

For the same vehicles, we also repair control units with the part numbers 89170-06820, 89170-06850, 89170-06880, 89170-33B90, 89170-33C30, 89170-33C50.

How does the repair of the 89170-33B50 work?

First you have the fault memory read out and attach the log to the unit. Then you disconnect the battery and remove the control unit. Then create the repair order online and send the unit packed securely. Processing at Airbag24 usually takes 3–4 working days.

Airbag24 checks the control unit on the test bench, repairs defective components, erases the stored crash data and tests the function. After that you receive your own unit back.

The sequence in the vehicle is binding for safety reasons. 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 89170-33B50 get to Airbag24?

You send the control unit 89170-33B50 to Airbag24 as a parcel, or book UPS collection for an extra charge. The repaired control unit is sent back to you by UPS.

Pack the printed repair order with it and secure the unit so that it withstands shocks.