Be cautious of the Mazda3/6 videos. Most are hack jobs by guys who really don't know what they are doing...ms2000, here's a link to a few YouTube videos:
Given that the Mazda 5 is based on the Mazda 3, the procedure should be the same. I should change mine at some point - our '09 is at 159K km. If you get to this before I do, please post details of your experience. (We're still in a deep freeze here; I doubt I'll do mine before April or May.)
Any system running too lean can be an indication of failed pcv (if pcv stuck closed)Dealer tells me if PCV fails, it caused OBD II error - but I can not trust him!
Do you guys have a master list of all the codes - does it show a code for PCV?
I did not see a code for PCV itself. But another m/c said that OBD will give a code say misfire etc. He thinks PCV is pretty much for life unless it fails.