Airbag control unit with part number 89170-42F20

What does the airbag control unit 89170-42F20 do?

The airbag control unit 89170-42F20 is the central control unit of the restraint system (SRS) for Toyota. It processes the crash sensor signals, selects the airbags and seatbelt pretensioners in an accident within milliseconds, and monitors the system continuously.

If the unit detects a fault, the airbag warning light in the instrument cluster lights up.

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

Why does the control unit 89170-42F20 fail?

Stored crash data is the most frequent cause of failure with 89170-42F20, after an accident and even if no airbag was triggered. Further causes are aged electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage peaks.

Stored crash data cannot be erased with an ordinary diagnostic tool. Airbag24 erases it during the repair.

Over time, electronic components age, solder joints go cold, and moisture or corrosion at plug connections disrupts the connection.

Voltage peaks, for example from a weak battery or a jump start, additionally strain the electronics.

How can you tell that the 89170-42F20 is defective?

A defect in the 89170-42F20 is recognisable from the airbag warning light in the instrument cluster, which stays on constantly or intermittently, from a fault message in the instrument cluster, from no connection to the diagnostic tool, or from a fault memory that cannot be cleared.

The warning light is the most important signal. It shows that the restraint system has detected a fault. A fault message in the instrument cluster and a diagnostic tool without connection also point to this.

In an emergency, airbags and seatbelt pretensioners may not trigger while the fault persists.

Which vehicles is the 89170-42F20 fitted in?

The control unit 89170-42F20 is fitted in the following vehicles: Toyota RAV4 XA50 (from 2018).

The list follows:

• Toyota RAV4 XA50 (from 2018)

Comparing the part number on the label of the removed unit with this page shows only whether it is the correct unit; that comparison says nothing more. Whether the control unit itself is defective, or whether a plug or cable is the cause, is decided only by a read-out fault memory.

For the same vehicles, we also repair control units with the part numbers 150800-4431, 152100-0262, 152100-4560, 89170-0R070, 89170-0R090, 89170-0R091.

How does the repair of the 89170-42F20 work?

First have the fault memory read out and enclose the log, then disconnect the battery and only then remove the control unit. Processing at Airbag24 usually takes 3–4 working days.

Then create a repair order online and pack the unit well before sending it in. Airbag24 checks the unit on the test bench, replaces defective components, erases stored crash data and runs a function test.

Finally 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 89170-42F20 get to Airbag24?

The control unit 89170-42F20 can be sent as a parcel, or you can book a UPS collection for an extra charge. The return to you after the repair is by UPS.

Put the printed repair order in the parcel and pack the unit shock-proof.