2017 Cvt Won't rev up when warm.

[Fummins]

I towed a 2017 Mirage(227,000km/141,000miles) to the shop the other day, driver said car wouldn't move and wouldn't rev up. It was hard to tell wth was going on cause every question I asked I got a yes for an answer. There were no codes stored, fluid looked good, car drove fine when I picked it up and when I road tested it twice. Dropped cvt pan, it looked good. Pulled kick panel, lowest connector had a tiny trace of corrosion just starting. I didn't think it was the cause as car ran fine with no codes with that connector unplugged. Took for another road test, seemed fine, verified proper cvt fluid level...

They picked the car up today, drove it about 20km and the same problem pulling into a parking lot, car wouldn't reve up. I drove it onto the trailer, scanned for codes immediately and found none stored. Fluid looks good still. I took if for another longer drive got it nice and hot then it started acting up while in DS. Surging at a constant speed. I headed back to the shop, pull into parking lot and there was no throttle response. No engine lights, car just wouldn't rev up. It was still in drive. It seemed to clunk kinda harsh going from neutral to drive which isn't typically a good thing. Eventually if the throttle was held to the floor it'd rev up like normal.

But after taking down the street a second time it shifted like crap, would rev way too high(WHILE DRIVING IN DRIVE NOT DS OR B). Just didn't act right at all.

After fiddling with it in the parking lot I managed to get c1396 and u0401. Likely a canbus wiring problem? Hopefully...