Check engine light

Hi guys, a few weeks ago I replaced my leaking injector oil seals. I removed the inlet manifold and had it cleaned etc. After putting everything back together, my engine check light came on. I got my local Nissan dealer to put their scan tool on it and it came up with EGR code found. They said I need a new egr and all gaskets and wiring harness to be checked as well. I bought a second hand egr from the wreckers and new gaskets and engine light still comes on. What should I be looking for apart from broken/melted wires etc. I’ve also replaced fuel, oil and air filters new oil, maf sensor cleaned.

G'day mate and welcome to the forum.

@AB @Doggy @mudrunntd @Growler someone want to shift this to the mechanical section so he gets a bit more help[

Is the egr blocked off at all? My engine light on my commonrail zd30 comes on a fair bit then goes comes back etc since blocking the egr, scan tool says it's egr but iv been told its normal once doing the block for a crd