Vauxhall Zafira fault code

I had the codes done on my car and the code came up egr valve i have had the egr valve off and i have had the intake manifold off and cleaned all the black carbon out as it had alot in it i have got it all back togever it runs ok till it gets hot and then it go's in to safe mode again its the same as it was befor i done anything the egr system valves are making a buzzing nose it dose not make any diffrance if you pull the pipes off or do i have to have the codes cleared befor it will run ok can anyone help thanks