CODE P042 Tollota Corolla CE 2003

Hello I have a problem with this P0420 code (Effectiveness of the Catalizer by Lower of the threshold refers to Bank 1) is a Toyota Corolla CE Motor 1ZZ VVT-I of 16 Valbules.
What sensor produces this faya where I place it and what to do? From beforehand thank you for the contribution.

If you refer to the Catalizer of seeing to be the problem of the oxygen sensor of bench 1, in my opinion.

Hello, this description will help you understand the problem. First of all you must make sure you have no escape on the escape system.


DTC: P0420 Catalizer Effectiveness below the threshold (Bank 1)
DESCRIPTION
This vehicle has two heated oxygen probes. One is located in front of the three -way catalytic converter (TWC) and the other behind. Signs emitted by probes become waveforms within the ECM. The frontal heated oxygen probe allows the ECM to supervise the air/fuel ratio and the signal of this probe asks ECM to control the feedback of the air/fuel ratio. As a result, the air/fuel ratio is balanced, and the wave shape of the front tube of heated oxygen oscillates regularly between rich and poor. To determine whether the TWC performance has deteriorated or not, the ECM compares the waveforms of the front and rear of heated oxygen. While the TWC works normally, the waveform of the rear tube of heated oxygen fluctuates between rich and poor more slowly than in the waveform of the front tube of heated oxygen. When the waveform of the heated oxygen rear tube fluctuates frequently, it indicates that the performance of the TWC has deteriorated.