how to fix P0420 code on my Toyota RAV4 Fifth Generation (2019-present)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is turned off.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench, multimeter

• Remove the upstream (pre-catalytic) oxygen sensor:

  1. Locate the upstream O2 sensor on the exhaust manifold.
  2. Use the O2 sensor socket to carefully unscrew and remove the sensor.
  3. Inspect the sensor for damage or contamination.
  4. Replace with a new O2 sensor if necessary. Torque the new sensor to the manufacturer’s specifications (typically around 30 ft-lbs).

• Remove the downstream (post-catalytic) oxygen sensor:

  1. Locate the downstream O2 sensor after the catalytic converter.
  2. Repeat the same removal and inspection process as with the upstream sensor.
  3. Replace if required and torque to specifications.

3. Check and Replace Catalytic Converter (if needed)

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool
• Inspect the catalytic converter for physical damage or blockage:
  1. If damaged, remove the catalytic converter from the vehicle.
  2. Use the socket set to remove bolts securing the catalytic converter to the exhaust system.
  3. Install the new catalytic converter and torque bolts to the manufacturer's specifications (typically 30-35 ft-lbs).

4. Reconnect Battery and Clear Codes

• Reconnect the battery terminals securely.
• Use the OBD-II scanner to clear any trouble codes.
• Start the vehicle and confirm that the check engine light is off.