To get to the ECU.....
First, get out your camera and take lots of photos as you go along for reference to put it back together.
You will need a fuel line removal tool and torx bits in addition to the normal tool... Plus lots of patience.
Remove the Fuel lines and electrical connection for the pump at the tank...
See this link
http://www.snowest.com/forum/showthread.php?t=80055
http://www.snowest.com/forum/showthread.php?t=139705
Then you need to remove the console... then the seat, rear storage box and the fuel tank... You do not need to drain the fuel tank
The ECU is on a bracket in front of the fuel tank.
No other way to remove it...
When handling the wiring harness and connectors... Do NOT yank on the wires. Also, When re installing everything, DO NOT zip tie the wires too tightly. The wiring harness on these sleds is a bit fragile and wires have been known to break inside the insulation without any indication from the outside.
When re istalling the fuel tank
When you put it back together, Install a new fuel filter... you can get it from
www.hiperf.com. About $25.
Good luck.