99 Lexus RX300 scanner shows po500 code but no check engine light on

Question

I switched sensors no difference I checked all the wiring to the ECM and speedometer I have 3 volts going through the system all reset the light I'll reset the light driver short distance go to park it before I shut off check engine light appears on Holly Woodlawn get back in it dryvit and the light goes off by itself but the code is still showing understanding I drove 70 miles last night after resetting the light checked it at the 70 mile marker no codes showed up and no check engine light Park then drove down to the store went to shut it off check engine light was on

Answer 1

Trans n engine works fine