Airbag control unit with part number 89170-02391

What does the airbag control unit 89170-02391 do?

The airbag control unit 89170-02391 is the central control unit of the restraint system (SRS) of Toyota. It evaluates the signals from the crash sensors, decides within milliseconds in an accident whether airbags and seatbelt pretensioners are triggered, and monitors the system continuously. It shows faults via the airbag warning light.

While driving, the unit checks sensors, wiring and output stages without interruption. Detected faults are stored in the fault memory, which a diagnostic tool can read out.

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

Why does the control unit 89170-02391 fail?

Stored crash data is the most common cause with the 89170-02391, even if no airbag was triggered; a standard diagnostic tool cannot erase it. Ageing electronic components, dry solder joints, moisture and corrosion at plug connections, and voltage spikes, for example from a weak battery or a jump start, can also be causes.

The crash data remains in the unit's memory after an accident, even if little damage can be seen on the car. Airbag24 erases it during the repair.

The other causes mainly affect the electronics themselves. Components age, dry solder joints can form, and moisture or rust weakens plug contacts. Voltage spikes additionally put strain on the circuitry.

How can you tell that the 89170-02391 is defective?

A defect in the 89170-02391 shows up as an airbag warning light in the instrument cluster that stays on permanently or intermittently, as a fault message in the instrument cluster, as a lack of connection to the diagnostic tool, or as a fault memory that cannot be cleared. In this state, the airbags and seatbelt pretensioners may not deploy in an emergency.

Typical signs are:

• The airbag warning light stays on permanently or keeps coming on.
• A fault message concerning the airbag system appears in the instrument cluster.
• The diagnostic tool does not establish a connection to the control unit.
• The fault memory cannot be cleared.

The warning light indicates the fault. If the light is on, have the vehicle checked promptly.

Which vehicles is the 89170-02391 fitted in?

The control unit 89170-02391 is fitted in these vehicles: Toyota Corolla E120 (2001-2004) and E120 Facelift (2004-2007). Before removal, compare the part number on the label of the unit with this page.

The following vehicles are recorded for this part number:

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

The label comparison only confirms that you have the right unit in front of you. Whether the control unit itself is defective, or whether a connector or cable is the cause, is shown only by the fault memory. Have it read out before any further steps.

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 89170-02391 work?

First read out the fault memory and enclose the log. Then disconnect the battery and only then remove the control unit 89170-02391. Create a repair order online and send the unit in well packed. Processing at Airbag24 usually takes 3–4 working days.

The sequence is binding for safety reasons: the control unit is removed only after the battery has been disconnected.

Airbag24 checks the unit on the test bench, replaces defective components, erases the stored crash data and carries out a functional test. The unit then goes back 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 89170-02391 get to Airbag24?

You choose the route to Airbag24 yourself: either you send the control unit 89170-02391 as a parcel, or you book a UPS collection for an extra charge. After the repair, Airbag24 returns the unit by UPS.

Enclose the printed repair order in the parcel and pack the unit shockproof.