Scanned my car and got the following codes "P0796" and "P0771" What does it mean?

Question

I bought used car Toyota Sienna XLE Limited 2005 V6 3.3 before 3 months. Before 1 month, the car was automatically braking. After that VSC and Check Engine light appeared.Then I took it to a mechanic and changed engine oil. Nothing had changed. After 2 weeks I took it to another mechanic and I changed the transmission oil. The old one was burnt black with small crashed metal particles. The automatic braking problem disappeared after some days.
Then a new problem appeared. When I pressed the gear pedal the car, the RPM went high but the mileage was low. It didn't go higher than 60kph. And also when I put on reverse the car didn't go back at all.
Then I bought "Autel Maxiscan 509" OBDII tool. I scanned the car myself and it showed me two codes. "P0796" and "P0771".
What can I do? Please help me!

Answer 1

P0796 Pressure control solenoid "C" perfromance

P0771 Shift solenoid "E" perfromance

When the transmission fluid is burnt and there is no reverse gear, with the transmission slipping. The solution for this is to get a rebuilt or another transmission. This is more of a internal mechanical condition , there nothing wrong with the solenoid  its operating range is outside its capability