I am an owner of 2010 Ralliart. I just reflashed EVO x TCU program and tuned the car . And I also changed the fluid and filter. Now I am suffering strange behaviors of my SST transmission. I have cleaned maf sensor but noting.

1. CEL on -- P187A Gear block 5th. The CEL will disappear in a few days (seems like it fixed by itself) but sometime it will be on again with Transmission service required message popping out. At that time, it will skip 5th gear. The message will stay on dashboard for 1 min, then the transmission service required message will disappear and all things will be normal.
2. Auto shift from 2nd gear to 3rd and to 4th gear in MANUAL mode sometime, not always.
3. shift very slowly between gears(NORMAL/SPORT AUTO/MANUAL) , especially 1st to 2nd, and rev will bounce during shifting interval when car is cold. (I think it's a tuning issue because after s-sport flashing and ecu tuing, I began to have this problem. and even worse since then) is that called rev hang issue?

The car now is drivable. I am out of warranty and I can't afford a new 13k sst. Do I need to rebuild or change an used one? Any advice is great for me.

 

Did all this happen after the TCU Flash & tune?


Who tuned it?


Go back to stock and see if it fixes it.

 

Try to teach-in shift forks.

 

Had the EXACT same issue in my SE. I got the same code and it would be as intermittent as you're describing. Luckily my extended warranty paid out because you'll have to get a new trans or rebuild yours at the very least. I suggest calling Kozmic if you're out of warranty.

NO you can't fix it, NO the teach in won't work, and NO it can't be saved. You're looking at a new trans or rebuild. Don't bother wasting money on a fluid change. It didn't slow the issue and definitely didn't fix it.