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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is on a flat surface and securely lifted.
• Disconnect the battery to prevent any electrical shorts.

2. Inspect and Replace Oxygen Sensors

1. Remove the upstream oxygen sensor:
   • Locate the upstream oxygen sensor near the exhaust manifold.
   • Use an oxygen sensor socket to carefully unscrew and remove the sensor.
2. Install the new upstream oxygen sensor:
   • Apply anti-seize compound to the threads of the new sensor (if not pre-coated).
   • Install the new sensor by hand first, then tighten with the sensor socket to the manufacturer’s specified torque (usually around 30 Nm or 22 ft-lbs).
3. Repeat for the downstream oxygen sensor:
   • Locate the downstream oxygen sensor, typically positioned after the catalytic converter.
   • Follow the same removal and installation process as for the upstream sensor.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Check for damage:
   • Inspect the catalytic converter for dents, cracks, or rust.
2. Remove the catalytic converter:
   • Loosen and remove the bolts connecting the catalytic converter to the exhaust system using a socket set.
   • Carefully remove any hangers or brackets holding the catalytic converter in place.
3. Install the new catalytic converter:
   • Position the new converter in place, ensuring proper alignment.
   • Reattach the exhaust bolts and tighten to the manufacturer’s specifications.
   • Reconnect any hangers or brackets.

4. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.