Airbag control unit with part number 89170-0D300

What is the function of the airbag control unit 89170-0D300?

The airbag control unit 89170-0D300 is the central control module for the Supplemental Restraint System (SRS) in the Toyota Yaris GR from model year 2020 onwards. It processes data from crash sensors and is responsible for the timely deployment of airbags and seatbelt pretensioners, ensuring the safety of vehicle occupants in the event of a collision.

As an SRS ECU (Supplemental Restraint System Electronic Control Unit), this component serves as the brain of the passive safety system. It continuously receives information from acceleration and pressure sensors distributed throughout the vehicle.

In the event of a collision, the control unit analyzes sensor data within milliseconds to determine the severity and nature of the impact. Based on this analysis, it decides which restraint systems—such as front airbags, side airbags, or seatbelt pretensioners—should be activated to provide optimal protection for occupants. Following activation, it also stores non‑erasable crash data.

Why does the control unit 89170-0D300 fail?

The most common faults of the control unit 89170-0D300 include stored, non‑erasable crash data after a collision and internal hardware defects, often indicated by error codes such as B1100 or B1205. Other causes include communication failures via the OBD interface or a permanently illuminated SRS warning light, signaling defective components on the circuit board.

A key reason for repair is the storage of crash data. After airbags or seatbelt pretensioners deploy, the control unit locks itself and registers a permanent fault code. This cannot be cleared using standard diagnostic tools, rendering the unit unusable.

Even without a collision, internal hardware issues can arise. Defective components on the circuit board, problems with memory chips, or cold solder joints can lead to malfunctions. These often manifest as specific error codes like B1100 (ECU malfunction) or B1205, pointing to an internal defect.

Additional failure causes may include moisture ingress due to vehicle leaks, fluctuating onboard voltage, or defects in wiring and connectors, all of which can result in internal damage to the control unit.

Related part numbers and compatibility

The control unit 89170-0D300 belongs to a family of Toyota airbag control units. Numbers such as 89170-0D020, 89170-0D440, or 89170-0D730 are technically closely related and often exhibit identical fault patterns. The TRW equivalent, part number 205881-104, also falls into this category and can be repaired.

Although software and configuration may vary depending on the model, these control units typically share a similar hardware platform. As a result, comparable issues—such as stored crash data or internal errors—occur across the entire model range. Repair is generally possible for all variants.

How do you recognize a fault in the control unit 89170-0D300?

A typical symptom is a persistently illuminated airbag or SRS warning light on the instrument cluster, even without an accident. Additionally, the control unit may become inaccessible to diagnostic tools, preventing the reading of fault memory. In this state, the entire airbag system becomes inoperable.

The most obvious sign is the SRS warning light that remains on after the engine starts. This indicates a critical fault in the restraint system and inevitably results in failure during the main vehicle inspection (HU).

Another clear indication is the lack of communication with the control unit. When a workshop attempts to read fault memory via the OBD interface, no response is received, suggesting a severe internal defect.

Following a collision—even one involving low impact energy where crash data has been stored—the system is likewise disabled. The corresponding fault entry cannot be erased, and the warning light stays on permanently. Consequently, occupant safety is no longer guaranteed.

In which vehicles is the control unit 89170-0D300 installed?

At Airbag24, we professionally refurbish the airbag control unit with part number 89170-0D300 for the sporty fourth-generation Toyota Yaris GR compact car (from model year 2020 onward). Our repair service covers all variants of this model equipped with this specific control unit.

This control unit is exclusively used in the following models:

Toyota Yaris GR (from model year 2020)

How is the airbag control unit 89170-0D300 professionally repaired?

Professional repair at Airbag24 begins with precise diagnostics to identify the root cause of the fault at the component level. Defective parts are then replaced, and crucially, crash data locked after a collision is reliably erased. Following repair, the control unit is fully functional again and ready for installation, backed by 2 years' statutory liability for defects.

Upon receipt of the control unit at Airbag24, our technicians perform a comprehensive analysis. Using specialized equipment, they read out the fault memory and internal data to pinpoint the exact cause of the defect—even if communication via OBD is no longer possible.

The actual repair is carried out at the electronic level. Defective components such as processors, memory chips, or sensor inputs are professionally replaced. Stored crash data is completely and irreversibly erased at the hardware level, ensuring the control unit functions like new again.

Following repair, the control unit is tested on a test bench to verify the flawless operation of all system components. After return shipping, it is ready for immediate installation (plug-and-play). Only the vehicle’s fault memory needs to be cleared once after installation.