2004 Ski-Doo REV Series Factory Service Manual, Page 211Get this manual
Section 05 2TEC ENGINE MANAGEMENT Subsection 02 (COMPONENT INSPECTION AND ADJUSTMENT)
Unscrew all retaining screws and remove the engine ECM from its supportInstall the new ECM to the supportReconnect ECM connectors to ECM, and then battery cablesTransfer the data from the previous ECM to the new one using B.U.D.Sthen proceed with the required resets and reprogram tether cord cap(s), if you were unable to transfer the dataNOTE: If data cannot be transferred, manually enter information in Vehicle tabAfter performing the required resets, ensure to clear all faults from the newly replaced ECMStart the engine and increase engine speed above 5000 RPM to be sure no fault appears
Removal
Remove air intake silencerDisconnect the wiring harness from all sensors actuatorsDisconnect the connector from the ECMCut all locking tie which are holding the wiring harness in positionRemove complete wiring harness
Installation
First connect the connector to the ECM and the engine connector to the vehicle wiring harnessReconnect the wiring harness to all sensorsactuators and reinstall all locking tie that have been removedInstall all remaining parts, which have been removed