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

Solution

1. Preparation

• Gather necessary tools and parts.
• Make sure the vehicle is parked on a flat surface and the parking brake is engaged.
• Disconnect the battery to ensure safety.

2. Inspect and Replace Oxygen Sensors

1. Remove the upstream oxygen sensor:

   • Use an O2 sensor socket to unscrew the sensor from the exhaust manifold.
   • Disconnect the electrical connector.

2. Install the new upstream oxygen sensor:

   • Apply anti-seize compound to the threads (if recommended).
   • Screw in the new sensor and tighten to manufacturer specifications (usually around 30-40 lb-ft).
   • Reconnect the electrical connector.

3. Repeat for the downstream oxygen sensor if it is also faulty:

   • Follow the same steps as above for removal and installation.

3. Inspect and Replace the Catalytic Converter (if necessary)

1. Remove exhaust components:

   • Loosen and remove the bolts securing the catalytic converter to the exhaust pipe and manifold using a socket set.
   • Carefully detach the converter from the exhaust system.

2. Install the new catalytic converter:

   • Position the new catalytic converter in place.
   • Reattach and tighten all bolts to the manufacturer's torque specifications (usually around 30-40 lb-ft).

3. Reconnect any sensors or components removed during the process.

4. Final Checks

1. Reconnect the battery.
2. Clear the error codes using the OBD-II scanner.