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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle's battery to ensure safety while working on electrical components.
• Raise the vehicle using a jack and secure it with jack stands.

2. Inspect Oxygen Sensors

• Tools Required: OBD-II scanner, multimeter
  • Remove the upstream (pre-catalytic) oxygen sensor using a socket.
  • Test the voltage output of the upstream sensor while the engine is running. It should fluctuate between 0.1 and 0.9 volts.
  • If the output is not within this range, replace the upstream oxygen sensor.

3. Inspect Catalytic Converter

• Tools Required: Socket set, torque wrench
  • Remove the bolts securing the catalytic converter to the exhaust system.
  • Visually inspect the catalytic converter for signs of physical damage, such as dents or rust.
  • If the converter is damaged or blocked, replace it with a new catalytic converter.

4. Replace Downstream Oxygen Sensor (if needed)

• Tools Required: Socket set
  • Remove the downstream (post-catalytic) oxygen sensor.
  • Install a new downstream oxygen sensor, ensuring it is properly torqued according to manufacturer specifications.

5. Reassemble and Clear Codes

• Reattach the catalytic converter and any exhaust components removed.
• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code and perform a test drive to ensure the code does not return.