(Copied from the old forum)
The check engine light started flashing. I could immediately tell that the fuel delivery went way rich and it seemed like the timing may have been retarded as well. At first I thought it may be hot, but the conditions didn't seem to make that very likely. I still pulled off into some softer snow just for the hell of it. No change. The light was still flashing and it was still in extra-rich mode.
I stopped the sled, shut the engine off and tried to find the source of the problem. I checked all the wires and connections that I could readily see. None appeared to have any issues. I verified by touching the head and cylinders that the engine wasn't really hot. Luckily we were already on our way back in anyway. I just rode it the last several miles on back to the truck with it in limp mode.
I noticed on the ride back that the check engine light wasn't just flashing steady. It was flashing a sequence: Six flashes, then a pause, six flashes, then a pause, repeat... Hmmm... The check engine light has apparently taken over the function of the red LED that the older EFI sleds had. The problem was that I didn't remember what a code 6 was.
I called the dealer today and asked if in fact the check engine light would flash a code. After a quick call to Cat he called back and said yes, the flashing sequence was a code 6. That indicates a problem in the APV servo motor circuit. Among the connections I had checked out on the trail, I had not-so-conveniently omitted a check of the APV servo motor wiring.
Sure enough, a quick check of the wiring to the servo motor revealed the trouble. The connector had popped out from behind the hose that runs to the left side running board cooler and had been rubbed-through by the secondary clutch when it shifted out and the movable sheave came closer to the middle of the sled.
I had thought I had gone over the sled fairly thoroughly when I first got it home, but I had missed that particular vulnerability. I had even added a bit of corrugated plastic wire loom to a couple areas that looked like they could use a bit more protection. This particular connector had just not caught my attention as an area that may give trouble.
The connector and the wires attached to it had been tucked reasonably neatly under the servo motor and to the inside of the hose. The jumping that I had done and rough sections that I had ridden earlier in the day was just enough to have it bounced the connector out of its formerly safe spot.
One zip tie securing the servo motor wiring to the hose could prevent this from causing you a problem. It's not a big issue, and may not effect that many of you. Just something that I figured other FireCat owners may want to take a look at.