The L-shaped graphene nanoribbon (GNR) interconnect is very significant for nanoelectronic and nanocircuits. There are some perturbations like defect treatment and the addition of suitable dopants in GNR to manipulate its transport properties. Here, we have investigated the conductance and transmission probability of L-shaped GNR interconnect by introducing defects in different regions using an open source Python-based simulation tool Kwant. The L-shaped defect-free GNRs produce nonzero conductance at Fermi energy. However, introducing a single or multiple single atom defect within the body, or a multi-atom defect at the corner decreases the conductance gradually resulting in a small conductance gap near zero Fermi energy. This is an indication of a transition from metallic to semiconductive nature. In addition, we have also introduced defects inside the corner region of L-shaped GNR. It is observed that the confinement of quasi-bound state in the defect region produces less conductance and simultaneously the number of conductance peaks increases at the same energy gap. It shows resonant tunneling behavior by introducing defects at the corner. Further, this study can add values in generating preferred conductance for different applications like switching /logic gates, CMOS architecture, embedded systems, etc., by introducing defects in the suitable regions of L-shaped GNR interconnect.