Airbag control unit with part number 89170-53540

What does the airbag control unit 89170-53540 do?

The airbag control unit 89170-53540 is the central control unit of the restraint system (SRS) for Lexus. It checks the signals from the crash sensors and decides within milliseconds in an accident whether airbags and seatbelt pretensioners are triggered.

It monitors the entire system without interruption. It shows faults via the airbag warning light and a message in the instrument cluster.

After an accident it stores crash data and locks itself.

Why does the control unit 89170-53540 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 include aged electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes.

The crash data remains stored after the accident, even if no airbag has deployed. That is precisely why it comes first when looking for the fault.

The other causes develop over time: the electronics age, moisture and corrosion attack plug connections, and cold solder joints disrupt the contact.

Voltage spikes, for example from a weak battery or a jump start, put additional strain on the electronics.

How can you tell that the 89170-53540 is defective?

A defect shows itself through an airbag warning light that stays on permanently or intermittently, a fault message in the instrument cluster, no connection to the diagnostic tool, or a fault memory that cannot be cleared. In that case airbags and seatbelt pretensioners may not deploy in an emergency.

These signs are:

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

The warning light is the system's direct notice and should be clarified promptly.

Which vehicles is the 89170-53540 fitted in?

The 89170-53540 is fitted in these vehicles: Lexus IS XE20 (2005-2009) and XE20 Facelift (2010-2013).

The vehicles for this part number are shown in the following overview.

• Lexus IS XE20 (2005-2009)
• Lexus IS XE20 Facelift (2010-2013)

Compare the part number on the label of the removed unit with this page, so that you can be sure it is the right unit. Also have the fault memory read out beforehand. This result alone shows whether the control unit itself is defective or whether a plug or a cable is the cause.

For the same vehicles, we also repair control units with the part numbers 89170-53110.

How does the repair of the 89170-53540 work?

First have the fault memory read out and attach the log. Then disconnect the battery and only afterwards remove the control unit. Then create a repair order online and send the unit in well packed.

Airbag24 checks the unit on the test bench, replaces defective components, erases the crash data and carries out a function test. The order of the steps is for safety reasons.

Processing at Airbag24 usually takes 3–4 working days.

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 89170-53540 get to Airbag24?

You send the unit in 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 in the parcel and pack the unit shockproof.