100% no.
DTC P0420
DESCRIPTION
A three-way catalytic converter (TWC) controls emissions of hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx). The
catalyst within the converter promotes a chemical reaction which oxidizes the HC and CO that are present in the exhaust gas. This process
converts these chemicals into water vapor and carbon dioxide (CO2), and will reduce the NOx, converting the NOx into nitrogen.
The catalytic converter stores oxygen. The efficiency of the TWC is determined by the measurement of the oxygen storage capacity (OSC). The
engine control module (ECM) measures the catalyst OSC by monitoring the heated oxygen sensor (HO2S) bank 1 sensor 2 and HO2S bank 2
sensor 2, during a steady state cruise. The ECM commands the air-to-fuel ratio lean and then rich for a calibrated number of cycles while
monitoring the response time of the HO2S 2. The ECM then establishes an average response time from subsequent air-to-fuel ratio cycles. The
difference of the average response time determines the OSC of the catalyst. If the ECM detects that this time difference is less than a calibrated
value, DTC P0420 or DTC P0430 sets.