I wonder if fundamental ethical values are mostly absorbed in childhood or through genetic instinct. At some point it seems most people would just use greater knowledge of law, ethics, etc to either become better at arguing why what they did was right or wrong or use the details to get better at not getting caught. Teaching a grown adult to internalize a new value system would appear quite difficult from my observation.
I have not met many people who wouldn't compromise their ethics for some benefit. This is especially true if they think nobody will find out. So I am not sure there are fundamental ethical values.