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

Solution

1. Preparation

• Gather all tools and parts required for the repair.
• Disconnect the vehicle's battery to prevent electrical shorts.

Tools Required:

• OBD-II scanner
• Socket set
• Torque wrench
• Multimeter
• Jack and jack stands

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
2. Use a socket to carefully remove the upstream oxygen sensor.
3. Inspect the sensor for damage and replace if necessary.
4. Repeat the removal and inspection for the downstream oxygen sensor.
5. Reinstall both sensors, ensuring they are properly torqued to manufacturer specifications (typically around 30 ft-lbs).

3. Inspect and Replace the Catalytic Converter

1. Raise the vehicle using a jack and secure it with jack stands.
2. Locate the catalytic converter in the exhaust system.
3. Inspect for any physical damage, rust, or blockage.
4. If necessary, remove the bolts securing the catalytic converter to the exhaust system using a socket.
5. Carefully detach the converter and replace it with a new unit.
6. Reinstall the bolts and tighten them to the manufacturer's torque specifications.
7. Reconnect any exhaust components that were removed.

4. Reconnect the Battery and Clear Codes

1. Reconnect the vehicle’s battery terminals.
2. Use the OBD-II scanner to clear the P0420 code from the system.
3. Start the engine and allow it to reach operating temperature.