Toyota Prius Firmware 34725200.cuw: Engine Control Calibration
Explore Toyota Prius calibration 34725200.cuw, its engine-control role and related service bulletins for starting, power and EGR faults.
Toyota firmware 34725200.cuw is an engine control calibration associated with Prius hybrid vehicles. The engine control module manages the gasoline engine’s operation, including fuel delivery and emissions-related functions, while working with the hybrid system as the engine starts and stops during driving.
The complete calibration ID 34725200 appears in Toyota service records as an updated calibration for certain engine-related warning-light conditions. It also appears as a previous calibration in later bulletins. Those roles describe the ID’s place in each bulletin, not a universal update path for every Prius.
Engine starting and power concerns
Toyota Service Bulletin T-SB-0041-15 and Canadian bulletin T-TCI-4315 list 34725200 as an updated calibration. They address a malfunction indicator light associated with diagnostic trouble codes P0171, P0A0F, P3190 and P3191. These codes can point to a lean air-fuel condition, an engine that failed to start, poor engine power or an engine that did not start.
In practical terms, the calibration belongs to the part of the vehicle’s software responsible for running the gasoline engine, rather than a navigation or multimedia system. The bulletins document the calibration’s relationship to these fault conditions, but the codes themselves do not establish the cause of a particular vehicle’s problem.
Later EGR-related service information
Toyota Canadian bulletin T-TCI-4467 lists 34725200 as a previous calibration in a malfunction indicator light bulletin involving P0401. That code indicates insufficient exhaust gas recirculation flow. The EGR system routes a controlled amount of exhaust gas back into the engine to help manage combustion temperatures and emissions.
Any improvement described by that bulletin belongs to its later revision, not automatically to 34725200. Toyota bulletin T-SB-0147-16 also lists this ID as a previous calibration.
The bulletins cover different groups of Prius, Prius PHV and Prius V model years. Their combined vehicle lists establish bulletin scope, not exact compatibility for every calibration ID. A vehicle’s existing calibration and the applicable service information are needed to identify the relevant record.