i recently bought a used 07 is350 with 127k miles. about a week after of it not being driven much due to it not being registered. my check engine and check vsc (trac light) is on. Codes: C1201 P0761(Shift Solenoid "C" Performance/Stuck Off) P0894(Transmission Component Slipping)P2174(Pressure Control Solenoid "D" Performance/Stuck Off)
UO121(Lost Communication With Anti-Lock Brake System (ABS) Control Module.Previous owner says he has no idea and that hes never had issues with the car. At first there was no noticeable performance issues but now my car most of the time will not shift above 3rd gear. Sometimes i can put the car into sport mode and use the paddle shifters to get it to shift into 4th and then it will run smoothly but more times it wont work then it will. i had a mechanic come check it out and he cleared my codes, drove it around , said my transmission felt fine and that it was most likely a faulty pcm but if not it would be my solenoids. Sometimes when my car is running "smoothly" in 2nd gear around 2-3k rpms my rpms start bouncing for a few seconds when accelerating. Im not too knowledgeable on cars as this is my first car but im a bit confused as why this only happens sometimes as ive tried to correlate it with something i could be doing but theres no pattern to it. ive cleared the codes a few times and most of the times my car will run without the issue for a few miles and eventually it will start acting up again and the light will come back on. However sometimes even with the light off it will continue to get stuck in 3rd and sometimes even with the light on it will shift smoothly out of 3rd into 4th, i wanted to see what you guys thought or if anyone has had this issue before .

 

When engine and transmission is cold especially during cold season often times it will not shift past 3rd gear until transmission fluid is warm. Try to warm up the car for few minutes before heading out.

 

i have tried this but it doesn't seem to make a difference

 

Can the transmission fluid history be established? Perhaps low fluid or may need to changed? Was the issue occurring in Normal mode, or while ECT was set to POWER?