how to fix P0420 code on my Toyota Camry XV70 (2018-2024)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to ensure safety while working on the electrical system.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream and downstream oxygen sensors:
  1. Locate the upstream O2 sensor (usually before the catalytic converter) and the downstream O2 sensor (after the catalytic converter).
  2. Use the O2 sensor socket to carefully unscrew both sensors.
  3. Inspect the connectors for corrosion or damage; clean or replace if necessary.
• Install new oxygen sensors:
  1. Apply anti-seize compound on the threads of the new sensors (if required).
  2. Torque to manufacturer specifications (typically around 30-40 ft-lbs).

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, jack stands, exhaust pipe cutter (if needed).
• Remove the old catalytic converter:
  1. Raise the vehicle securely using jack stands.
  2. Disconnect the exhaust pipe from the catalytic converter using a socket set or exhaust pipe cutter.
  3. Unbolt the catalytic converter from the exhaust manifold and remove it.
• Install the new catalytic converter:
  1. Position the new catalytic converter and bolt it to the exhaust manifold.
  2. Reconnect the exhaust pipe and ensure all connections are secure.
  3. Torque the bolts to manufacturer specifications.

4. Reset the Check Engine Light

• Reconnect the battery and clear the fault codes using an OBD-II scanner.
• Start the vehicle and let it idle for a few minutes.