Rear hatch operation

[elmitchell57]

I have a 2016 Nissan Rogue SL. At 64000km, (warranty ended at 60000), the rear hatch went up as normal when activated, and I stepped under it, only to be hit on the back of the head by the hatch coming back down, fast. So that happens every time now, hatch goes all the way up, and immediately comes down fast to the halfway point. I have tried a reset, no resolution. I took the vehicle to the dealership, and they say it is both shocks, and the estimate for repair was $2000. I told them to forget it. To me, it appears to be an electronics control fault, and not both shocks failing at the same time. If I push it back up manually and let it go, it forcefully comes back down to the halfway point. A couple of times I have reset (by holding the close switch for 10 seconds) while holding it at full open, and it still comes down hard, but when the close switch was pushed, instead of closing, it went full open and back down to halfway point, and I had to close it manually. Next time opening, it is back to original fault. So how can the shocks themselves be faulty? How do I go about checking the control system, where is it, etc. Anyone with any ideas, any help is appreciated.

[VStar650CL]

The shocks aren't shocks, they're planetary-drive gearmotors with encoders built-in. The planetaries are what allow them to be moved manually like a gas strut. It sounds like one of the encoders is shot, but which one will be hard to determine without a scanner that can read the encoders in realtime. The gen2's have been out long enough that there are tons of them in JY's, I'd get a used set. They're not too tricky to install but the wires do run underneath the headliner, so the back half of the liner needs to drop a few inches. That isn't so easy because of the way the rear trim is assembled. The factory installation puts the lower trim in last, which means to do it by the book you need to remove the lower first. In practice the lower doesn't need to be completely removed, but it does need to be pulled back at the seam between the lower and upper to allow the upper C-D Pillar trim to come loose.