CONSTRUCTION
The airbag ECU assembly consists of judgment circuits, a deceleration sensor, a ignition control circuit, a safing sensor, a backup power circuit, a diagnostic circuit and a memory circuit.
| Item | Outline |
|---|---|
| Judgment Circuit | Judgment circuits are built into the airbag ECU assembly to judge the severity of a collision using the acceleration/deceleration signals from the front airbag sensors, door side airbag sensors and No. 2 side airbag sensor assemblies. |
| Deceleration Sensor | A deceleration sensor is built into the airbag ECU assembly. This sensor distorts in the event of a collision. The amount of distortion is based on the deceleration rate of the vehicle during a frontal collision and is converted into an electric signal. |
| Ignition Control Circuit | The ignition control circuit performs calculations based on the signal output from the judgment circuit of the airbag ECU assembly, front airbag sensors, door side airbag sensor and side airbag sensor assemblies. If the calculated values are greater than the specified values, the airbags are deployed. |
| Safing Sensor | During a frontal, side or rear side collision, this sensor turns on and outputs an on signal to the airbag ECU assembly if the deceleration rate of the safing sensor is greater than a specified value. |
| Backup Power Circuit | The backup power circuit consists of a power supply capacitor and a DC-DC converter. When the power supply to the airbag ECU assembly is disrupted during a collision, the power supply capacitor is charges and supplies electric power to the system. The DC-DC converter operates as a boosting transformer when the battery voltage falls below a predetermined level. |
| Diagnostic Circuit | The diagnostic circuit constantly monitors for system malfunctions. When a malfunction is detected, it turns on the SRS warning light in the combination meter assembly to inform the driver. |
| Memory Circuit | When a malfunction is detected by the diagnostic circuit, a DTC is stored in memory. |