How many catalytic converter has a 2000 Montero Sport 3.5L? Had one service/replace in 2012 with P0421 warm up cat at bank 1. Just today I had another issue - P0431 warm up cat at bank 2. Tech said another cat converter needs to be service/replace. Just need opinion from anyone that knows Montero Sport.

 

V6 engines have catalytic converter on each bank - thus Bank 1 and Bank 2 errors. It also has one or two catalytic converters further down the line after all the O2 sensors. Those are fed from both banks at the same time. These downstream catalytic converters do not play any role in setting the Warm up Catalytic Efficiency codes. They do play a role if you have to pass emissions, but the vehicle's computer has no way of checking those by itself.