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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to ensure safety during repairs.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench, multimeter.
• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Use the O2 sensor socket to remove the upstream sensor.
  3. Inspect the sensor for any signs of damage or contamination and replace if necessary.
  4. Repeat for the downstream sensor if testing indicates a fault.
  5. Install new sensors and torque them to the manufacturer’s specifications (typically around 30 ft-lbs).

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust gasket, penetrating oil.
• Sub-steps:
  1. Safely raise the vehicle using jack stands and remove the underbody cover if applicable.
  2. Unbolt the catalytic converter from the exhaust manifold and the exhaust pipe using the socket set.
  3. Inspect the catalytic converter for physical damage, clogging, or contamination (e.g., carbon build-up).
  4. If damaged, replace the catalytic converter with a new one, ensuring to use a compatible OEM or high-quality aftermarket part.
  5. Install with new gaskets and torque bolts to manufacturer specifications (refer to service manual for exact values).

4. Reset the Check Engine Light

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the battery if it was disconnected.
  2. Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.