Rep Power: 0

Hello - first post for me so if this is the wrong area to post this issue please let me know.

I have a, new to me, 2009 Civic LX w/35K miles. It is throwing P2647 P0523 and P1077 trouble codes.
While inspecting the VTEC Solenoid, I noticed rodent damage on the cable run/harness that enters the top of the engine (passenger side. see photo).
One wire (white with black stripe?) appears to be severed completely. However, I cannot figure out how to remove that cable harness from the back of the engine so that I may work on it. Releasing the tab on the end where it terminates doesn't appear to do anything. The harness feels as if it's glued or taped in at its point of termination.
I'd like to try to fix this myself, but I will need to figure out how to extract that harness from its point of termination.
Any hints tips or videos on the subject are appreciated.

Passenger Side. Facing Firewall. Cable bundle enters near oil cap.

 
Rep Power: 222

Think that part is snapped down onto a stud. You may have to disconnect more to get enough slack in the harness