how to fix the P0420 code on my Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical issues during the repair.

Tools Required:

• OBD-II scanner
• Multimeter
• Socket set
• Torque wrench
• Jack and jack stands

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
2. Disconnect the electrical connectors from both sensors.
3. Use a socket wrench to remove the sensors from their respective locations.
4. Install new oxygen sensors by threading them into place, and tighten to manufacturer's torque specifications.
5. Reconnect the electrical connectors.

3. Assess and Replace Catalytic Converter

1. Inspect the catalytic converter for any visible damage; if necessary, proceed with removal.
2. Disconnect the exhaust pipes from the catalytic converter using a socket set.
3. Remove any mounting bolts or brackets holding the catalytic converter in place.
4. Install the new catalytic converter, ensuring proper alignment with the exhaust system.
5. Secure it with mounting bolts and reconnect the exhaust pipes, tightening to the specified torque.

4. Reset the Engine Control Module (ECM)

1. Reconnect the battery.
2. Use an OBD-II scanner to clear the P0420 code from the ECM.
3. Start the engine and allow it to reach operating temperature.