Toyota 89665-02031 Firmware Catalog Reference
Catalog details for Toyota firmware identifier 89665-02031 and its tentative engine-control module association.
89665-02031 is a Toyota firmware identifier associated tentatively with the 89665 engine-control computer part-number family. An engine control module manages engine operation by processing sensor signals and controlling functions such as fuel injection and ignition timing.
The complete identifier does not establish the exact vehicle application or a specific software change. The general role of the controller family should not be taken as evidence that this particular calibration modifies any named engine-control behavior.