Airbag control unit with part number 89170-33A20

What does the airbag control unit 89170-33A20 do?

The airbag control unit 89170-33A20 controls the restraint system (SRS) of Lexus. It evaluates signals from the crash sensors, determines in an accident within fractions of a second which airbags and seatbelt pretensioners are triggered, and monitors the entire system during operation.

If the unit reports a fault, the message appears via the airbag warning light. After an accident it stores crash data and locks itself.

If this control unit fails, the system can no longer make a reliable selection in an emergency. Such failures should not be left open.

Why does the control unit 89170-33A20 fail?

The most common cause is crash data stored after an accident, even if no airbag has deployed; with a normal diagnostic tool it cannot be erased. In addition there are aged electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes.

Crash data results from sensor signals that the unit classifies as a relevant impact. Whether an airbag has deployed does not follow from this. With common diagnostic tools the data cannot be removed when the unit is installed.

Other causes arise independently of this. Aged components, cold solder joints, and moisture and corrosion at plug connections affect the electronics. Voltage spikes, for example from a weak battery or a jump start, can also cause damage.

How can you tell that the 89170-33A20 is defective?

An airbag warning light that stays on permanently or intermittently shows the defect reliably, as does an error message in the instrument cluster. Even if the diagnostic tool cannot connect to the control unit, or the fault memory cannot be cleared, there is a problem. In that case airbags and seatbelt pretensioners may not trigger in an emergency.

The airbag warning light in the instrument cluster is the most important sign. Whether it burns continuously or only lights up intermittently makes no difference to the assessment; in both cases the finding should be checked.

An error message in the instrument cluster is an additional sign. If the connection to the diagnostic tool fails, or the fault memory remains after an attempt to clear it, that is a further indication.

Please have the finding checked promptly, because airbags and seatbelt pretensioners may not trigger in an emergency.

Which vehicles is the 89170-33A20 fitted in?

The control unit 89170-33A20 is fitted in these vehicles: Lexus ES ASV60 (2012-2015). You can check whether your vehicle is among them by make and model.

These vehicles are known to us for this part number:

• Lexus ES ASV60 (2012-2015)

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

For the same vehicles, we also repair control units with the part numbers 89170-06880, 89170-33860.

How does the repair of the 89170-33A20 work?

First read out the fault memory and include the log, then disconnect the battery and only 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 order is fixed for safety reasons. The control unit may only be removed once the battery has been disconnected, and disconnecting follows the read-out.

At Airbag24 the unit is checked on the test bench, defective components are repaired or replaced, stored crash data is deleted, and a function test is carried out. Afterwards your own unit is returned 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 89170-33A20 get to Airbag24?

You send the control unit 89170-33A20 as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 sends it back to you by UPS.

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