check the wiring connector on the passenger side where it plugs into the transmission, I've heard of pins of the connector getting bent/mushed and causing this code...also check for any burned, melted, or chaffed sections of the entire transmission wiring harness. just a thought, might not be electrical related, my next guess would be the lock-up solenoid, then depending on the transmission builder, my next guess would be related to a pump modification, and a spring change some of the builders make to help lock up pressure...I've heard of the spring causing issues. PI converters come with a spring to change in the pump...some builders use it, some don't. Good luck.