how to fix P0420 code in Toyota Corolla E210 (2019-2024)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface with the parking brake engaged.
• Wear safety gloves and goggles.

2. Inspect Exhaust System

• Sub-steps:
  • Raise the vehicle using jack stands.
  • Inspect the exhaust manifold, pipes, and catalytic converter for visible cracks or holes.
  • Repair or replace any damaged components as necessary.

3. Test Oxygen Sensors

• Tools Required: Multimeter
• Sub-steps:
  • Locate the upstream and downstream oxygen sensors.
  • Disconnect the sensors and test their resistance with a multimeter.
  • Compare readings to manufacturer specifications; replace any sensors that are out of range.

4. Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust gasket
• Sub-steps:
  • Remove the oxygen sensors from the catalytic converter.
  • Unbolt the catalytic converter from the exhaust system.
  • Install the new catalytic converter, ensuring to use a new exhaust gasket.
  • Torque the bolts to manufacturer specifications.

5. Reinstall Oxygen Sensors

• Sub-steps:
  • Reconnect the upstream and downstream oxygen sensors.
  • Ensure that the sensors are securely fitted and not cross-threaded.