Toyota Firmware 89663-04B25: Engine Control Calibration

Toyota firmware 89663-04B25, identified in service records by the full calibration ID 8966304B2500, belongs to the engine control module calibration family. The engine control module manages engine operation and monitors emissions-related systems. Its software helps coordinate functions such as fuel delivery and ignition, while checking for faults that can illuminate the malfunction indicator light, commonly called the check-engine light.

Check-engine light and P261093

Toyota service bulletin T-SB-0013-19 lists 8966304B2500 as an updated calibration in connection with a malfunction indicator light and diagnostic trouble code P261093. That code concerns the engine control module’s internal engine-off timer performance. The bulletin associates this calibration with a software revision for the reported warning-light condition. It does not mean that every vehicle showing the code has the same cause.

T-TCI-5191 also lists the calibration as updated for the P261093 warning-light topic. The timer is part of the controller’s monitoring logic rather than a driver-operated feature. A fault detected in that logic can bring on the check-engine light even though the driver may not notice a change in how the vehicle runs.

Service-record context

Toyota also lists 8966304B2500 as an updated calibration in T-SB-0119-18, a bulletin covering 2016–2018 Tacoma models. The available record does not identify that bulletin’s service topic, so it should not be assumed to describe the same condition as P261093.

The P261093 bulletins cover several Toyota models, including Tacoma, Prius, Prius Prime, Sienna and Camry. Those are the scope of the bulletins, not a confirmed fitment list for this individual calibration. The complete calibration ID is the useful identifier when distinguishing this record from other engine-control software.