P0420
DTC P0420: Catalyst System Efficiency Below Threshold (Bank-1)System and Wiring Diagram
System And Wiring Diagram:
System Description
ECM monitors oxygen concentration in the exhaust gas which has passed the warm up three way catalytic converter by HO2S. When the catalyst is functioning properly, the variation cycle of HO2S output voltage (oxygen concentration) is slower than that of A/F sensor output signal because the amount of oxygen in the exhaust gas is stored in warm up three way catalytic converter.
A/F Sensor Description
Refer to A/F Sensor Description.
DTC Detecting Condition and Trouble Area
DTC Detecting Condition And Trouble Area:
DTC Confirmation Procedure
WARNING:
^ When performing a road test, select a place where there is no traffic or possibility of a traffic accident and very careful during testing to avoid occurrence of an accident.
^ Road test should be carried out with 2 persons, a driver and a tester, on a level road.
NOTE: Check to make sure that the following conditions are satisfied when using this "DTC Confirmation Procedure".
EVAP leak check model:
^ Engine coolant temperature: 70 °C (158 °F) to 150 °C (302 °F)
^ The following DTCs are not detected: DTCs related to A/F sensor and HO2S
Non-EVAP-leak-check model:
^ Intake air temperature at engine start: -10 °C (14 °F) to 80 °C (176 °F)
^ Intake air temperature: -10 °C (14 °F) to 70 °C (158 °F)
^ Engine coolant temperature: 70 °C (158 °F) to 150 °C (302 °F)
^ Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)
^ The following DTCs are not detected: DTCs related to ECT sensor, IAT sensor, MAF sensor, barometric pressure sensor, A/F sensor and VSS
1. Connect scan tool to DLC with ignition switch turned OFF.
2. Turn ON ignition switch and clear DTC using scan tool.
3. Start engine and warm up to normal operating temperature.
4. Increase vehicle speed to 50 - 60 mph (80 - 100 km/h).
5. Keep above vehicle speed for 10 min. or more.
6. Stop vehicle.
7. Check whether catalyst readiness/monitoring test has completed or not by using scan tool. If catalyst readiness/monitoring test has not completed, check vehicle conditions (environmental) and repeat Steps 4) through 6).
8. Check DTC and pending DTC.
DTC Troubleshooting
