Airbag control unit with part number 89170-02491

What does the airbag control unit 89170-02491 do?

The airbag control unit 89170-02491 is the central control unit of the restraint system (SRS) for Toyota. It evaluates the signals from the crash sensors, decides in an accident within milliseconds which airbags and seatbelt pretensioners are triggered, and monitors the system continuously. Faults are shown via the airbag warning light.

The sensors supply the readings from which the control unit derives whether an accident has occurred and which restraint devices must be activated. Even during normal driving it checks the components involved continuously, so that a fault is noticed as early as possible.

After an accident the control unit stores crash data and locks itself.

Why does the control unit 89170-02491 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 to consider are aged electronic components, cold solder joints, moisture and corrosion on plug connections, and voltage spikes.

The crash data remains stored in the control unit until it is specifically removed, and this is exactly what makes the finding so stubborn. Which of the other causes applies can hardly be narrowed down without testing.

The other causes at a glance:

• aged electronic components
• cold solder joints on the circuit board
• moisture and corrosion on plug connections
• voltage spikes, for example from a weak battery or a jump start

How can you tell that the 89170-02491 is defective?

A defect shows itself through the airbag warning light in the instrument cluster, which stays on constantly or intermittently, through a fault message in the instrument cluster, through a diagnostic tool without a connection to the control unit, and through a fault memory that cannot be cleared.

The signs at a glance:

• airbag warning light that stays on constantly or intermittently
• fault message in the instrument cluster
• diagnostic tool that cannot connect to the control unit
• fault memory that cannot be cleared

In such a case, airbags and seatbelt pretensioners of the vehicle may possibly fail to deploy in an emergency. The warning light is therefore the direct sign that something is wrong with the restraint system.

Which vehicles is the 89170-02491 fitted in?

The airbag control unit 89170-02491 is fitted in these vehicles: Toyota Corolla E120 (2001-2004) and E120 Facelift (2004-2007). You can check whether your car is among them on the label of the unit.

In detail, the following vehicles are concerned:

• Toyota Corolla E120 (2001-2004)
• Toyota Corolla E120 Facelift (2004-2007)

Compare the part number on the label of the removed unit with this page; this only ensures that you have the correct unit in front of you. Also have the fault memory read beforehand, because only the log 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 89170-02180, 89170-02240, 89170-02390, 89170-02411, 89170-02G60, 89170-12160.

How does the repair of the 89170-02491 work?

First have the fault memory read and attach the log. Only then disconnect the battery and remove the 89170-02491. Next, create a repair order online and send the unit in well packed.

At Airbag24 the unit is checked on the test bench, defective components are replaced, the stored crash data is deleted, and a function test follows. 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 89170-02491 get to Airbag24?

You send the control unit 89170-02491 as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 returns it to you by UPS.

Put the printed repair order in the parcel and pack the unit securely against shocks.