this code said "catalyst system efficiency below threshold (Bank 1) what does this mean? wht could be bad?

 

your number 1 cat is bad .... or has something to do with that 02 sensor in your cat

this is how you fix it .... pull your cat out!

 

This is how you go about geting it fix. If you haven't yet, take the car a shop that you trust. Please stay away from your local lexus dealership as they will not be of any help to you. You want to have o2 sensors tested to insure proper function, and the cats. I had the same problem on my
sc but P0430 wich is (bank2) took it to lexus and they told me that the o2 sensor need to be replace. $200 later I still had the same problem. Took the car back in and the cat on bank 2 is bad. The moral of the storry is the dealer is not your friend they are there to make you spend as much as posible. Have the car properly diagnose and then you can work on geting it fix. I you have any ? you can PM me.