2006 Ski Doo REV Service Shop Manual, Page 288Get this manual
Section 06 ENGINE MANAGEMENT (SDI) Subsection 03 (COMPONENT INSPECTION, REPLACEMENT AND ADJUSTMENT)
Check piston conditionRemove exhaust system and reed valves on intake sideVerify piston condition through the intake and exhaust portsLook for scoring on piston skirtsScored piston skirts may result in RER working erratically making you think the problem is an electronic problemWhen it does not work at all, check wiring and STARTRER switch as explained aboveIf everything is normal, try another ECM
DESS POST VERIFICATION
If short beeps are not heard when starting the engine, refer to DIAGNOSTIC PROCEDURESThe following continuity tests can also be performed using an ohmmeterDisconnect DESS post wires