Airbag control unit with part number 89170-50L53

What does the airbag control unit 89170-50L53 do?

The airbag control unit 89170-50L53 is the central control unit of the restraint system (SRS) for Lexus. It evaluates the signals from the crash sensors, decides within milliseconds in an accident which airbags and seatbelt pretensioners are triggered, and monitors the system continuously. After an accident it stores crash data and locks itself; the lock is lifted only by the repair.

The unit reports faults via the airbag warning light in the instrument cluster. While driving, it continuously checks sensors, output stages and the connections to the triggers, so that a fault becomes visible as early as possible.

Why does the control unit 89170-50L53 fail?

The most common cause is stored crash data after an accident, even if no airbag was triggered; a normal diagnostic tool cannot delete it. Other causes are ageing electronic components, dry solder joints, moisture and corrosion on plug connections, and voltage spikes, for example from a weak battery or a jump start.

The unit itself creates the crash data and keeps it until it is deliberately removed. Airbag24 clears it during the repair, so the unit comes back without it.

The other causes develop over time. Solder joints and plug contacts age, moisture attacks contacts, and voltage spikes when starting can strain circuits. If recurring warnings occur, have the power supply and the plugs checked first, which rules out one cause before the unit goes in for testing.

How can you tell that the 89170-50L53 is defective?

A defect shows itself through the airbag warning light in the instrument cluster, which lights up permanently or intermittently, through a fault message in the instrument cluster, through a missing connection to the diagnostic tool, or through a fault memory that cannot be cleared. Then airbags and seatbelt pretensioners may fail to deploy in an emergency.

A lit warning light is therefore a clear reason to have the system checked promptly. The light indicates a detected fault, even if the vehicle behaves inconspicuously in everyday use.

If there is no connection to the diagnostic tool, the stored fault cannot be read out, and you do not learn what the unit has reported. In that case, a check of the system is the next step.

Which vehicles is the 89170-50L53 fitted in?

The control unit 89170-50L53 is fitted in these vehicles: Lexus LS XF50 (from 2018).

You will find the vehicles for which this control unit is intended in the overview below.

• Lexus LS XF50 (from 2018)

Before removal, compare the part number on the label of the unit with this page. This only confirms that you have the correct unit in front of you. Also have the fault memory read out, because only the result shows whether the control unit itself is defective or whether a connector or cable is the cause.

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 89170-50L53 work?

First have the fault memory read out and place the log in the parcel, disconnect the battery and only then remove the control unit 89170-50L53. Then create a repair order online and send the unit in well packed. Airbag24 needs 3–4 working days as a rule for testing, repair and the function test.

At Airbag24 the unit is first examined on the test bench, defective components are repaired and stored crash data is deleted. A function test follows, after which 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 89170-50L53 get to Airbag24?

You send the control unit 89170-50L53 to Airbag24 as a parcel, or you book a UPS collection for an extra charge. After the repair, Airbag24 returns the unit to you by UPS.

Insert the printed repair order into the parcel and pack the unit shock-proof so that it arrives undamaged.