Airbag control unit with part number 89170-53570

What does the airbag control unit 89170-53570 do?

The airbag control unit 89170-53570 is the central control unit of the restraint system (SRS) for Lexus. It evaluates the signals from the crash sensors, decides within milliseconds in a crash on airbags and seatbelt pretensioners, and monitors the system continuously. Faults are reported via the airbag warning light; after a crash the unit stores crash data and locks itself.

During operation the unit continuously checks its connections to sensors and output stages.

When a genuine impact is detected, it evaluates the measured values and initiates the appropriate deployment. The electronics are designed for this.

Why does the control unit 89170-53570 fail?

The most common cause is stored crash data, even when no airbag has deployed, and a standard diagnostic tool cannot erase it. Other causes are aged electronic components, cold solder joints, moisture and corrosion on plug connections, and voltage spikes, which also affect the control unit 89170-53570 as they do other units.

Crash data records what the sensors measured in an impact. It remains stored until it is deliberately erased.

Aged electronic components and cold solder joints may not show up straight away.

Moisture and corrosion attack plug connections, and voltage spikes add further strain to the circuitry. A weak battery or jump-starting can cause such spikes.

How can you tell that the 89170-53570 is defective?

The airbag warning light in the instrument cluster stays on permanently or intermittently, and a fault message appears in the instrument cluster. The diagnostic tool gets no connection to the control unit 89170-53570, or the fault memory cannot be cleared. Airbags and seatbelt pretensioners may then fail to deploy in an emergency.

These features are clear reasons to have the fault memory read out:

• Instrument cluster warning light on permanently or intermittently
• Fault message in the instrument cluster
• Missing connection to the diagnostic tool
• Fault memory cannot be cleared

A warning that goes out after a restart is no reliable proof that the fault has been fixed.

Which vehicles is the 89170-53570 fitted in?

The airbag control unit 89170-53570 is fitted in these vehicles: Lexus IS XE20 (2005-2009) and XE20 Facelift (2010-2013).

The following vehicles are on record for this control unit.

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

Comparing the part number on the label with this page only confirms that you have the correct unit. Whether the control unit is defective or a plug or cable is the cause is shown only by the fault memory, which you should have read out beforehand.

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

How does the repair of the 89170-53570 work?

First have the fault memory read out and attach the log, then disconnect the battery. Only then remove the control unit 89170-53570, create a repair order online and send the unit off well packed. Processing at Airbag24 normally takes 3–4 working days.

The sequence serves your safety. You only send the unit once the repair order is in place.

Airbag24 tests the unit on the test bench, repairs defective components, erases crash data and carries out a function test. Afterwards the 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 89170-53570 get to Airbag24?

You send the control unit 89170-53570 as a parcel or book a UPS collection for an extra charge. After the repair Airbag24 returns it to you by UPS. Enclose the printed repair order in the parcel and pack the unit shock-resistant.

Filling material in the carton prevents the unit from shifting during transport.