how to fix P0420 code on my Toyota Camry Eighth Generation (2018-present)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Ensure the vehicle is parked on a level surface and use jack stands if needed.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream (pre-catalytic) oxygen sensor:
  1. Locate the upstream oxygen sensor near the engine.
  2. Use the O2 sensor socket to unscrew the sensor.
  3. Install the new oxygen sensor and torque it to manufacturer specifications (typically around 30 ft-lbs).
• Repeat for the downstream (post-catalytic) oxygen sensor if necessary.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust gasket.
• Locate the catalytic converter:
  1. Remove the exhaust heat shield if applicable.
  2. Unbolt the catalytic converter from the exhaust manifold and exhaust pipe.
  3. Inspect the old catalytic converter for blockages or damage.
  4. Install the new catalytic converter with new gaskets, tightening the bolts to manufacturer specifications (typically around 30 ft-lbs).

4. Reset the Engine Control Module

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code from the ECM.