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

Solution

1. Preparation

• Gather the necessary tools and parts.
• Disconnect the battery to prevent any electrical shorts.
• Ensure the vehicle is on a level surface and raise it safely using jack stands.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream (pre-catalytic converter) oxygen sensor.
  • Sub-step: Use the O2 sensor socket; turn counterclockwise to remove.
• Install the new oxygen sensor.
  • Sub-step: Torque the sensor to the manufacturer’s specifications (usually around 30 ft-lbs).
• Repeat the process for the downstream (post-catalytic converter) oxygen sensor if necessary.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, wrench set, torque wrench, exhaust gasket.
• Remove the exhaust pipes connected to the catalytic converter.
  • Sub-step: Unbolt the flanges and remove any hangers.
• Inspect the catalytic converter for internal damage or clogging.
• If needed, replace the catalytic converter.
  • Sub-step: Install the new converter using new gaskets and torque bolts to the manufacturer’s specifications (generally 25-30 ft-lbs).

4. Reconnect Battery and Clear Codes

• Reconnect the battery terminals.
• Use the OBD-II scanner to clear the P0420 code from memory.