Then there most likely still an issue with the throttle control motor, any new scans may show the TCM is faulty. The voltage should be more towards 0.65 vdc, so the TCM may not be doing it's job(as indicated by the previous code). I would keep the TPS's voltage set lower, reset the ECU by battery disconnect, and re-scan to check for any new codes. I'm assuming you are testing VTA(white/red stripe wire) to the brown ground wire. When you reset the ECU, it sets all memory back to stock parameters. If it is still in limp mode, you'll have one or more DTC's. Chances are your TCM code may come back.
'02 IS300 MSM LSD