The conflict between the formal law enforcement code of ethics and the police subculture or "COP CODE" is that all police officers are also human beings first. They are fathers or mothers, husbands and wives, daughters and sons and just people who have chosen mostly to help and protect and, in a round a bout way make society better.
The conflict is not that of a "group" but better defined on an individual basis. When a person decides to become a police officer they are deciding to lose their circle of friends, be treated differently and become a very small minority. Even if they don't plan on changing or becoming "someone else" they will... eventually.
Soon after becoming a police officer your circle of friends becomes other officers because they are the only ones who actually know what the hell you are talking about and they will listen and understand and have had the same experiences.
Police officers see things that aren't meant to be seen and never have time to process the seedy nasty disgusting things that they see on a daily basis. They turn to other officers and "vent" to relieve stress or tension or to just plain feel better.
So this is why the public percieves police culture as so closed and secret. It's not really. It is just the way police conduct their affairs. But the public goes on thinking that everything is a "scam" or "cover up" or hidden under the "thin blue line." It's amusing to me because I always felt the same way. Now with 7 years on the job I know it is the farthest thing from the truth. I've been to job related trainings miles and miles from home with other officers from all over the United States and even though I may not know anyone at the training I can sit down with an officer from New Mexico, California, and Florida and we all can talk like we grew up together because we all have Cop Experience that is similar and have all been in similar situations.
I think the ethical problems you are hinting to may be tied to this "buddy bond" or "blue brotherhood" or whatever you wish to call it. I'm sure there was a time where it played an important role in how police conducted business on a daily basis. At that time police organizations were there for "enforcement" and recieved terrible pay and terrible benefits, if any. Listening to stories from cops who served the public in the 60's and 70's it was a different time and unfortunate that police officers were seen as the "enemy" to the public.
With increase in pay, strict hiring requirements, and a more business like approach to daily activities there are not many organizations that can conduct business now as was once done 3 decades ago. Not to say a bad apple can't slip through the cracks every now and then because we all know they do but most officers are not going to jeopardize their income, family, reputation, retirement, and job for one of these bad apples and most officers have probably never felt pressure to "do the wrong thing" or "cover up a brother." If you mess up you mess up. Cops are people and the organizations they work for know this. Accept the mistake, be honest about it, deal with it, and move on.
The other conflict you may be talking about is the "life experience" one. Cops with much life experience may experience conflict during their daily routine.
Example.
I pull over a vehicle with dad, mom, and 3 crying kids coming from walmart. Dad and mom are barely making ends meat and it's obvious. They were mildly speeding. Everything checks out... am I going to write a ticket to these people?
Probably not... been there done that and I can sympathize with what is going on.
Take the new hire who is 22, fresh out of the academy, still living with mom and dad. He will probably write them because it was an obvious violation of traffic law in his jurisdiction and a statistic to boot.... is he helping that family?
No.
The important thing to remember is cops are people and any "Cop Code" that the public sees or imagines isn't really there. The only "Cop Code" that exists is that we all took an oath to protect and serve. We all are in it to help and nothing more and that makes us all brothers and sisters.
Hope this helps.