how to fix P0420 code on my Toyota Camry Eighth Generation (2018-present)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool down.

2. Inspect and Replace Oxygen Sensors

1. Locate the oxygen sensors: Identify the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
2. Remove the upstream oxygen sensor:
   • Use an oxygen sensor socket or wrench.
   • Disconnect the electrical connector.
   • Unscrew the sensor from the exhaust manifold.
3. Install the new upstream oxygen sensor:
   • Apply anti-seize compound on the threads (if not pre-applied by the manufacturer).
   • Screw it in by hand and tighten to manufacturer specifications (typically 30 lb-ft).
   • Reconnect the electrical connector.
4. Repeat for the downstream oxygen sensor if required.

3. Inspect and Replace the Catalytic Converter

1. Remove the exhaust pipe:
   • Use a socket set to unbolt the exhaust pipe from the catalytic converter.
   • Carefully slide the exhaust pipe off.
2. Remove the catalytic converter:
   • Unbolt it from the exhaust manifold and any mounting brackets.
   • Remove any heat shields if present.
3. Install the new catalytic converter:
   • Position the new catalytic converter in place.
   • Bolt it securely to the exhaust manifold and the exhaust pipe.
   • Reattach any heat shields that were removed.
4. Reinstall the exhaust pipe: Secure it back to the catalytic converter.

4. Clear Codes and Test Drive

1. Reconnect the negative battery terminal.
2. Use the OBD-II scanner to clear the P0420 code.
3. Test drive the vehicle for at least 30 minutes under various driving conditions to ensure the repair is effective.