In case anyone runs into this problem: another undocumented (?) fail-safe scenario is that in case of a knock-sensor code, the transmission will not shift into higher gears. Just experienced this on a 2005 LS430 with P0328 knock sensor code (bank 1). Transmission would not go higher than 4th gear. Not a single ATM code. It was also impossible to shift up manually or use switch to 5th or 6th gear using bi-directional Techstream active tests. After temporarily fixing the knock sensor code by a sensor 1 -> sensor 2 bypass, the transmission started shifting normally.