Airbag control unit with part number 89170-42D70

What does the airbag control unit 89170-42D70 do?

The airbag control unit 89170-42D70 is the switching centre of the restraint system (SRS) of Toyota. It evaluates the crash sensors, determines in an accident which airbags and seatbelt pretensioners are triggered, and monitors the system continuously.

The calculation takes place within a few fractions of a second; only that way can triggering be initiated in time. Outside an accident the unit constantly checks whether all components of the system work properly.

It stores detected faults in its memory and displays them via the airbag warning light. After an accident the control unit secures crash data and locks itself. Only the repair lifts the lock.

Why does the control unit 89170-42D70 fail?

The most frequent cause is crash data after an accident, even when no airbag has fired. Ordinary diagnostic tools cannot erase this data. In addition, ageing components, corrosion at plug connectors and voltage spikes come into consideration.

The crash data remain in the memory even if the airbag did not fire. The diagnostic tool cannot access them, which is why they can be noticed again at every later check.

Another area concerns the electronics themselves. Components age, and solder joints can develop cracks that become visible only in a test.

Furthermore, influences from the vehicle electrical system have an effect. Voltage spikes, for example from a weak battery or jump-starting, stress the circuits and can leave damage behind.

How can you tell that the 89170-42D70 is defective?

A defect shows up as the airbag warning light in the instrument cluster, which lights up permanently or intermittently. In addition fault messages appear in the instrument cluster, and the diagnostic tool does not find the control unit.

These signals are clear enough to have the system checked. Typical signs are:

• Airbag warning light permanently or intermittently on
• Fault message in the instrument cluster
• Missing connection between diagnostic tool and control unit
• Fault memory cannot be cleared

With such a finding, airbags and seatbelt pretensioners may possibly not fire in an emergency. Therefore have the system checked in good time.

Which vehicles is the 89170-42D70 fitted in?

According to our assignment, the control unit 89170-42D70 is listed in these models: Toyota RAV4 XA50 (from 2018).

These vehicles are listed with us:

• Toyota RAV4 XA50 (from 2018)

For one, compare the part number on the label of the removed unit with this page, which only confirms the identity of the unit. For another, have the fault memory read out beforehand. Only the log shows whether the control unit is defective or whether a plug or cable causes the fault.

For the same vehicles, we also repair control units with the part numbers 150800-4431, 152100-0262, 152100-4560, 89170-42400, 89170-42870, 89170-42A60.

How does the repair of the 89170-42D70 work?

Processing at Airbag24 generally takes 3–4 working days. Airbag24 checks the unit on the test bench, repairs defective components, erases the crash data and carries out a function test.

Beforehand you read out the fault memory, disconnect the battery and remove the control unit. Then you create the repair order online.

The time allowance refers exclusively to the work at Airbag24.

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 89170-42D70 get to Airbag24?

You send the unit as a parcel or book a UPS collection for an extra charge. After the repair it comes back to you by UPS.

Enclose the printed repair order in the parcel. Pack the unit shock-proof.