What does a p0173 fuel trim bank 2 mean for 2000 Mazda millenia?

Answer 1

Mine is Millenia 2001 2.3L turbo.

One of the bad design of Mazda millenia was they used plastic T connector easily perishable by high engine heat. It is ok for several years but after several years the T's will get eroded and break and exhause air sensor malfunction will occur.

There are three white plastic T's under the engine cover on top of the engine.

Two of them can be easily located, but one is under the turbo system fixture set, so it is not possible to replace this hard to reach one without disassembling the whole turbo system.

It is tons and tons of work to remove the turbo sucks. It is really bad design.

I had P0173 and I found that all three T's got broken. I could replace two of them easily but the last one under the turbo system was impossible. I still have P0173.