Airbag control unit with part number 89170-0C640

What does the airbag control unit 89170-0C640 do?

The airbag control unit 89170-0C640 is the central control unit of the restraint system (SRS) for Toyota. It evaluates the signals from the crash sensors and, in the event of an accident, decides within milliseconds which airbags and seatbelt pretensioners are triggered. After an accident it stores crash data and locks itself.

During operation the unit monitors the entire restraint system continuously. If it detects a fault, it shows it via the airbag warning light in the instrument cluster.

Because the triggering decision has to be made so quickly, the control unit depends on a stable power supply and clean sensor signals.

Why does the control unit 89170-0C640 fail?

The most common cause is crash data stored after an accident, even if no airbag was triggered. Other causes are aged electronic components, cold solder joints, moisture and corrosion at plug connectors, and voltage spikes, for example from a weak battery or a jump start. Airbag24 erases the crash data when repairing the 89170-0C640.

A normal diagnostic tool cannot erase this crash data, so it stays in the memory until the unit is worked on in the workshop.

Aged components and cold solder joints develop gradually, while voltage spikes from the vehicle electrics can suddenly load the unit.

How can you tell that the 89170-0C640 is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently, and an error message appears in the instrument cluster. The diagnostic tool cannot connect to the 89170-0C640, and the fault memory cannot be cleared. In an emergency, airbags and seatbelt pretensioners may then fail to trigger.

A light that comes on only occasionally and then goes out again should also be checked.

An error message alone does not show whether the control unit itself is affected or only a wire. Please have the system read out at a workshop promptly.

Which vehicles is the 89170-0C640 fitted in?

The 89170-0C640 is fitted in these vehicles: Toyota Tundra K30 (2007-2021).

The list below shows the vehicles in which this control unit was installed.

• Toyota Tundra K30 (2007-2021)

Please check two things before removal. Compare the part number on the label of the removed unit with this page so that you can be sure it is the correct unit. Also have the fault memory read out beforehand, because only the log 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 89170-0C440, 89170-0C450, 89170-0C451, 89170-0C452, 89170-0C490, 89170-0C581.

How does the repair of the 89170-0C640 work?

First have the fault memory read out and attach the log, then disconnect the battery and only then remove the 89170-0C640. Then create a repair order online and send the unit in well packed. Processing at Airbag24, i.e. checking, repairing and testing, usually takes 3–4 working days.

Airbag24 checks the unit on the test bench, replaces defective components, erases stored crash data and carries out a function test. The repaired unit, which is your own, is then returned to you.

For safety reasons the order of removal is fixed: first the read-out, then the battery, and only after that the removal.

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 89170-0C640 get to Airbag24?

You send the 89170-0C640 as a parcel or book a UPS collection for an extra charge. After the repair Airbag24 sends the unit back to you by UPS.

Put the printed repair order into the parcel and pack the unit shock-resistant.