I think the main difficulty lies in capturing the correct mood of the verb. This text seems to be talking about tattooing in a rather mystical sense. "Possess" just seemed a little awkward here, as often English uses a more basic verb than the French. I also think that codes should be clarified, possibly as "codes of practice".

Another suggestion - basically some different verbs from those already suggested, and a different way of dealing with the codes.

I agree with the "art of tatooing" suggestion.

Hello,

Traditional knowledge is imparted by tattooing and basic codes are indicated by them.

porte des savoirs traditionnels = carries with itself traditional knowledge

I hope this helps.

... carries traditional knowledge/beliefs (note the plural in savoirs) ...

From reading your whole passage I get the idea that the overall issue is how to deal with traditional values and meaning in a postmodern world, with the imminent danger that the practice of tattooing and the motifs themselves (as cultural artefacts and carriers of meaning and certain beliefs) are deprived of their (spi)ritual meaning and absorbed by a “debased trivial culture”.

In this context, below article might be of interest (although it does not mention tattooing):
http://www.theage.com.au/opinion/triumph-of-the-trivial-life...
Some critics did predict the triumph of the trivial. In his 1957 essay, A Theory of Mass Culture, Dwight MacDonald foresaw our "debased trivial culture that voids both the deep realities and also the simple spontaneous pleasures", adding that "the masses, debauched by several generations of this sort of thing, in turn come to demand trivial cultural products".