Infiniti i30 01 ECM problem

[smart2010]

Does anyone knows the couse of the problem when the MIL light of the infiniti I30 2001 does not light up when i removed any sensor cable like engine cam shaft sensor ...etc and also the ECM does not communicate with OBDII scan tool to know exactly the problem.I had before an Air bag alarm when i did a maintenace of AC without removing the batt terminal then i reseted manually through ignition switch ON,OFF procedures.I really do not know wheather this way will disable the MIL light and couse not to light up. Please help