how to fix the P0420 code on my Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Ensure the engine is cool before starting work.
• Disconnect the negative terminal of the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Step 1: Locate the upstream and downstream oxygen sensors.
  • Tools Required: O2 sensor socket, ratchet, and extension.
• Step 2: Disconnect the electrical connectors from both oxygen sensors.
• Step 3: Remove the upstream oxygen sensor first using the O2 sensor socket.
• Step 4: Install the new upstream oxygen sensor and tighten it to the manufacturer's torque specification (typically around 30 lb-ft).
• Step 5: Repeat the process for the downstream oxygen sensor.

3. Inspect and Replace Catalytic Converter (if necessary)

• Step 1: Inspect the catalytic converter for any signs of damage or clogging.
• Step 2: If replacement is needed, remove the exhaust pipe bolts securing the catalytic converter.
  • Tools Required: Socket set and penetrating oil.
• Step 3: Carefully detach the catalytic converter from the exhaust system.
• Step 4: Install the new catalytic converter, ensuring all gaskets are replaced and securing bolts are tightened to the specified torque (typically around 40-50 lb-ft).

4. Reset OBD-II System

• Step 1: Reconnect the negative battery terminal.
• Step 2: Use an OBD-II scanner to clear the P0420 code from the system.

5. Test Drive

• Step 1: Start the vehicle and allow it to reach operating temperature.
• Step 2: Take the vehicle for a test drive, monitoring for any check engine light illumination or performance issues.