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

Solution

1. Preparation

• Gather tools and parts required for repair.
• Disconnect the negative terminal of the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

1. Remove the upstream oxygen sensor:
   • Use an oxygen sensor socket to carefully unscrew the sensor from the exhaust manifold.
   • Inspect the sensor for any signs of damage or contamination.
2. Install the new upstream oxygen sensor:
   • Apply anti-seize compound on the threads (if applicable).
   • Install and torque to manufacturer's specifications (typically around 30 lb-ft).
3. Repeat for the downstream oxygen sensor if necessary.

3. Inspect and Replace the Catalytic Converter (if needed)

1. Remove the catalytic converter:
   • Unbolt the exhaust pipes connected to the catalytic converter using a socket set.
   • Remove any heat shields if present.
2. Inspect the old catalytic converter:
   • Check for any signs of physical damage, discoloration, or excessive carbon buildup.
3. Install a new catalytic converter:
   • Position the new catalytic converter and secure it with the bolts.
   • Ensure all gaskets are in place and seal properly.
   • Torque bolts to the specified value (typically around 30 lb-ft).

4. Clear Codes and Test Drive

1. Reconnect the battery:
   • Reattach the negative terminal.
2. Use the OBD-II scanner:
   • Clear the P0420 code from the vehicle's memory.
3. Test drive the vehicle:
   • Drive for at least 20-30 minutes to allow the vehicle to cycle through the readiness monitors.