Your dealing with:
A vehicle with 204,000 miles.
Had extremely dirty ATF
After 2 flushes it still throwing a code.
One of the most common reasons for this code is debris obstructing the flow of transmission fluid throughout the transmission valve body.
It may also be that the internal pump might be going bad.
Being this is not occurring at first drive would lead me to discount a wiring issue.
But could still be a solenoid or torque converter issue
Futher diagnotics would be required before part swapping begins.
- This reply was modified 6 months, 3 weeks ago by Richard Kirshy.