Airbag control unit with part number 89170-52J40

What does the airbag control unit 89170-52J40 do?

The airbag control unit 89170-52J40 is the central processing unit of the restraint system (SRS) for Toyota. In an accident it evaluates the sensor signals and decides within milliseconds which airbags and seatbelt pretensioners are triggered.

During operation the unit checks all components of the system. If a fault is detected, the airbag warning light in the instrument cluster lights up and shows the malfunction.

If an accident occurs, the control unit stores the crash data and locks itself afterwards. The lock is part of this control unit's function.

Why does the control unit 89170-52J40 fail?

The most common cause is crash data stored after an accident, even without a deployed airbag. A normal diagnostic tool cannot erase it. Added to this are aged electronic components, cold solder joints, moisture and corrosion at plug connectors, and voltage spikes, for example with a weak battery or a jump start.

After the event the crash data remains stored in the unit and cannot be removed with usual diagnostic technology. As a result the fault persists.

Electronic ageing and damp contacts cause faults that appear only gradually. A cold solder joint, for example, can remain unremarkable for a long time and then trigger a fault.

How can you tell that the 89170-52J40 is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently, and an error message appears in the instrument cluster. In addition, the diagnostic tool cannot establish a connection to the control unit, and the fault memory cannot be cleared.

The warning light is the sign to watch out for. As long as it is on, airbags and seatbelt pretensioners may possibly not deploy in an emergency.

If the connection to the diagnostic tool fails, it is likely that the control unit itself is affected. Only the fault memory, which you have read out before removal, gives a reliable answer.

Which vehicles is the 89170-52J40 fitted in?

The control unit 89170-52J40 is used in these vehicles: Toyota Aqua NHP10 (2011-2015), NHP10 1st Facelift (2015-2017) and NHP10 2nd Facelift (2017-2021).

The following vehicles are assigned to this part number:

• Toyota Aqua NHP10 (2011-2015)
• Toyota Aqua NHP10 1st Facelift (2015-2017)
• Toyota Aqua NHP10 2nd Facelift (2017-2021)

Compare the part number on the label of the removed unit with this page to confirm that it is the right unit. Also have the fault memory read out, because only this result shows whether the control unit or a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 152100-4560, 89170-42D50.

How does the repair of the 89170-52J40 work?

You read out the fault memory and attach the log before disconnecting the battery. Only then remove the control unit, and create the repair order online. Processing at Airbag24 usually takes 3–4 working days.

Pack the unit well and send it together with the repair order. The steps follow a fixed sequence that serves safety.

At Airbag24 the unit is checked on the test bench, defective components are repaired, and the crash data is erased. Finally a function test follows, and your own unit 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 89170-52J40 get to Airbag24?

You send the unit as a parcel, or book a UPS collection for an extra charge. Airbag24 sends the repaired unit back to you by UPS afterwards.

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