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

Solution

1. Preparation

• Gather necessary tools and parts.
• Park the vehicle on a flat surface and engage the parking brake.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, socket set, torque wrench.
• Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
• Use the O2 sensor socket to remove the upstream oxygen sensor; inspect the wiring and connector for damage.
• If damaged, replace the sensor with a new one.
• Repeat the process for the downstream oxygen sensor if necessary.
• Torque the new sensors to the manufacturer's specifications (typically around 30-40 Nm).

3. Inspect and Replace Catalytic Converter (if needed)

• Tools Required: Socket set, wrench set, jack and jack stands.
• Raise the vehicle using a jack and secure with jack stands.
• Inspect the catalytic converter for any signs of damage or blockage.
• If replacement is necessary, remove the bolts securing the catalytic converter, and disconnect any exhaust hangers.
• Install the new catalytic converter, ensuring a tight fit and proper alignment.
• Torque the bolts to the manufacturer’s specifications.

4. Clear Codes and Test Drive

• Reconnect the battery and use the OBD-II scanner to clear the P0420 code.
• Test drive the vehicle for at least 20-30 minutes to allow the ECM to monitor the catalytic converter's performance.