Help diagnose Misfires, P2152 Supply Voltage for Fuel Injector Group C


I’m stuck diagnosing a misfire on my RS4. I have major misfires in cylinders 5 & 6, and have fault code P2152 Supply Voltage for Fuel Injector Group C. I’ve been searching for threads with similar issues and all I can find our people having misfires due to a failing 614/644 relay. I’m fairly certain (but not positive) that is not my issue since my misfires are very specific to a particular circuit and not happening in any other cylinders. Also car starts up just fine. There are really no other symptoms. Only other problem I have ever had was the car going into limp mode after going through a car wash, and research suggested that was because water got into the ECU box.

Most of what I have found in search of an answer says I likely have a bad wire connection but I don’t know where to look. I can’t find a diagram or better yet just pictures of the fuel injectors circuit and those running the Group C injectors. Could someone point me to something that could direct me exactly where I should look? Is there a fuse for the different injector groups? I was hoping it would be an easy fix like a fuse. Do I have to take the manifold off to look at all places there might be a short?

Any help is much appreciated. Thanks