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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety during the repair.
• Raise the vehicle securely on jack stands.

2. Inspect and Replace Oxygen Sensors

1. Remove the upstream oxygen sensor:

   • Locate the upstream O2 sensor (before the catalytic converter).
   • Use an O2 sensor socket to remove it.
   • Disconnect the electrical connector.

2. Replace the upstream O2 sensor (if necessary):

   • Install the new O2 sensor and torque it to the manufacturer's specifications (typically around 30-40 ft-lbs).
   • Reconnect the electrical connector.

3. Remove the downstream oxygen sensor:

   • Locate the downstream O2 sensor (after the catalytic converter).
   • Use an O2 sensor socket to remove it.
   • Disconnect the electrical connector.

4. Replace the downstream O2 sensor (if necessary):

   • Install the new O2 sensor and torque it to the manufacturer's specifications.
   • Reconnect the electrical connector.

3. Inspect and Replace the Catalytic Converter

1. Inspect the catalytic converter:

   • Check for physical damage, rattling, or exhaust leaks.

2. Remove the catalytic converter:

   • Loosen the bolts or clamps securing the catalytic converter to the exhaust system.
   • Remove the catalytic converter from the exhaust system.

3. Install the new catalytic converter:

   • Position the new catalytic converter and secure it with bolts or clamps.
   • Torque bolts to the manufacturer's specifications.

4. Reset the ECU

1. Reconnect the battery:

   • Reconnect the negative terminal of the battery.

2. Clear the error codes:

   • Use an OBD-II scanner to clear the P0420 code from the ECM.