Please need profesional advice here! Problem with Check Engine light! ;(

Hello and happy new year !
As the topic says, I was watching a topic in the “Step By Step section” and there is a topic about “How to Figure out your Check Engine Light code“ and inside it tells like a self diagnostics of the ECU “Turn the ignition switch to ON ( II ), Then turn it back to off three times. “ Then I went to my car and I notice that the Check Engine light doesn’t turn ON!!! I think that the last owner had a problem and he disconnected the light, so: What can I do to fix it? Where could it be disconnected? Any help I would really appreciate!

Thanks