2005 Ski-Doo Tundra, Skandic, Expedition Shop Manual, Page 352Get this manual

Section 06 ENGINE MANAGEMENT (4-TEC) Subsection 03 (COMPONENT INSPECTION AND ADJUSTMENT)
WARNING
Never make spark test with spark plug removedFlammable vapors may be present in the engine compartment and ignited which could cause an explosionR1004motr150B

If wiring harness is good, try new ECMRefer to ECM REPLACEMENT procedures elsewhere in this sectionOtherwise, repair the connector or replace the wiring harness between ECM connector and OPS
Voltage Test WARNING

• ATV
• Jet Ski
• Outboard Motors
• Personal Watercraft
• Snowmobiles
• Stern Drives