Airbag control unit with part number 89170-50L70

What does the airbag control unit 89170-50L70 do?

The airbag control unit 89170-50L70 coordinates the SRS restraint system of Lexus. It checks the signals from the crash sensors, decides within fractions of a second in a crash whether airbags and seatbelt pretensioners are triggered, and reports faults to the airbag warning light.

The control unit runs throughout the entire drive and checks the connected components continuously. After a crash, it stores crash data and locks itself.

Why does the control unit 89170-50L70 fail?

Stored crash data is the most common cause: after a crash the unit retains it even if no airbag has deployed, and a normal diagnostic tool cannot remove it. Aged components, cold solder joints, moisture on the plugs and voltage spikes from a weak battery or a jump start are also possible causes.

Airbag24 removes the crash data during the repair. The other causes concern the electronics and their connections.

Whether one of these is present is determined by testing on the test bench, not by looking from outside.

How can you tell that the 89170-50L70 is defective?

Signs of a defect are an airbag warning light that lights up permanently or intermittently, an error message in the instrument cluster, a diagnostic tool with no connection, and a fault memory that cannot be cleared.

Typical signs at a glance:

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

In an emergency, the airbags and seatbelt pretensioners may then fail to deploy. Therefore have the system checked promptly.

Which vehicles is the 89170-50L70 fitted in?

The control unit 89170-50L70 is fitted in these vehicles: Lexus LS XF50 (from 2018). The part number determines the assignment, the model name alone does not.

Here is the list of vehicles in which this control unit has been recorded so far.

• Lexus LS XF50 (from 2018)

Comparing the label with this page only confirms that you have the right unit. Whether the control unit itself is defective or a plug or cable is the cause is shown only by the fault memory. Have it read out before removal.

For the same vehicles, we also repair control units with the part numbers 89170-50K81, 89170-50K83, 89170-50L00, 89170-50L03, 89170-53790, 89170-53820.

How does the repair of the 89170-50L70 work?

First read out the fault memory and enclose the log. Then disconnect the battery, remove the control unit, create a repair order online and pack the unit well for shipping.

Airbag24 checks the unit sent in on the test bench and replaces defective components. The team erases the stored crash data, followed by a function test.

Checking, repairing and testing at Airbag24 usually takes 3–4 working days. 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 89170-50L70 get to Airbag24?

You send the control unit as a parcel or book a UPS collection for an extra charge. After repair, Airbag24 returns it by UPS.

Pack the control unit shock-resistant so that it survives transport undamaged.