1993 Lexus LS 400 check engine light

I have a 1994 l_s 400 and the check engine in overdrive light was thinking it's my first mark so I take it to the shop and he said he reset the mass air flow sensor and 2 other Sensors the light is still flashing he also told me that after cooling and heating the car at least 7 times it should go off I just want to know is that true