So I have a few codes that come up on Civic

So I have a few codes that come up on civic. One is p1259- Vtech system malfunction.

Currently, the car does not go past 23 MPH and if I try to its at 4,000 to 5,000 rpms with no change in speed or power.

I was told that most likely it was a clogged vtech solenoid, so I took it off and cleaned it and it didn't change the way the car drives.

I'm having trouble figuring this out and I'm not sure what else to do.