how to fix P0420 code on Toyota RAV4 Fourth Generation (2013-2018)

Solution

1. Preparation

• Gather necessary tools and parts.
• Park the vehicle on a level surface and set the parking brake.
• Disconnect the battery's negative terminal to ensure safety.

2. Inspect Exhaust System

• Tools Required: Socket set, jack and jack stands
  • Raise the vehicle and secure it on jack stands.
  • Visually inspect the entire exhaust system for cracks, loose connections, or any signs of wear.
  • Tighten any loose bolts or connections.

3. Check Oxygen Sensors

• Tools Required: Multimeter
  • Locate the upstream and downstream oxygen sensors.
  • Disconnect the electrical connectors from the sensors.
  • Use a multimeter to test each sensor’s voltage output:
    • Upstream should fluctuate between 0.1V to 0.9V when the engine is running.
    • Downstream should be relatively stable, indicating it’s not faulty.

4. Replace Faulty Components

• Tools Required: Socket set, torque wrench
  • If an oxygen sensor is faulty, replace it by removing the old sensor and installing a new one.
    • Torque specifications for oxygen sensors typically range between 30-40 ft-lbs.
  • If the catalytic converter is damaged or clogged, replace it:
    • Remove the bolts connecting it to the exhaust system.
    • Install the new catalytic converter and tighten bolts to manufacturer specifications.

5. Reconnect and Test

• Reconnect the battery’s negative terminal.
• Start the engine and allow it to reach operating temperature.
• Clear the P0420 code using an OBD-II scanner and take the vehicle for a test drive to monitor for any reoccurrence of the code.