The cat needs to be very very hot to work on a Mazda.
Some testers will run all the electrics and rev the engine to get it really hot I have seen the emmisions drop as the temp goes up.
On one of my old Mazdas I used to rag it up a steep hill and it then went straight into the test bay for the emmisions test with the cat almost red hot.
Not many garages will let you do that.
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