I have cleaned the Oxygen Sensor Electrical connection side with CRC-contact cleaner ! but its not the end again yesterday morning i found Check Engine Light ON ! When i checked for any leak in the Exhaust ,there was leak & welded & fixed it.
when i restarted it,warning still present! then switched off the engine ,removed the battery main terminal,again connected after 20 secs,then started the engine,Check Engine Light is Off now !!! I dont know when it will come again !!! If its happen again ,next time i will not hesitate to remove & replace the catalytic converter cost 200 dhs !!!! if that doesnt work ,finally i will have to change the oxygen sensor,that will be the culprit ! Also i am hearing that Check Engine Light On may be on because of Engine Electrical System too. But the code which i received is P0420-catalyst emission below threshold !!! i will keep you all updated if i can able to fix this problem once for all...cheers have a safe drive