how do I fix the P0420 code on my Toyota Camry XV70 (2018-2024)

Solution

1. Preparation

• Gather tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream oxygen sensor (pre-catalytic converter) by:
  1. Locating the sensor on the exhaust manifold or downpipe.
  2. Using the O2 sensor socket, unscrew the sensor.
  3. Install the new sensor by threading it into place and tightening to the manufacturer’s specified torque (usually around 30-35 lb-ft).
• Repeat the process for the downstream oxygen sensor (post-catalytic converter) if necessary.

3. Check and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust gasket, penetrating oil.
• If the catalytic converter is faulty:
  1. Loosen the exhaust bolts connecting the catalytic converter to the exhaust system.
  2. Use penetrating oil if bolts are rusted.
  3. Remove the catalytic converter and inspect for internal damage (e.g., rattling or melted substrate).
  4. Install the new catalytic converter, ensuring a proper fit and alignment.
  5. Use new exhaust gaskets and torque bolts to the manufacturer’s specifications.

4. Reconnect Battery and Clear Codes

• Reconnect the battery terminals.
• Use the OBD-II scanner to clear the P0420 code and any other stored codes in the system.