how to fix P0420 code in my Toyota Corolla E140 (2006-2013)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to prevent electrical issues.
• Allow the engine to cool down if it has been running.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, torque wrench.
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors (before and after the catalytic converter).
  2. Unplug the electrical connectors from both sensors.
  3. Use an O2 sensor socket to remove the sensors from the exhaust system.
  4. Install new oxygen sensors, ensuring they are tightened to the manufacturer’s torque specifications (usually around 30 lb-ft).
  5. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, cutting tool (if necessary), gaskets.
• Sub-steps:
  1. Inspect the catalytic converter for any signs of damage or blockage.
  2. If replacement is needed, unbolt the catalytic converter from the exhaust system.
  3. If welded, use a cutting tool to carefully remove the converter.
  4. Install the new catalytic converter using new gaskets and bolts, torquing them to manufacturer specifications.

4. Clear Error Codes

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0420 code from the engine control module.