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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, infrared thermometer, safety glasses, gloves.
• Ensure the vehicle is parked on a level surface and the engine is off.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

1. Locate the oxygen sensors. The upstream sensor is typically located before the catalytic converter, and the downstream sensor is after it.
2. Disconnect the wiring harness. Use a flathead screwdriver if necessary to release any clips.
3. Remove the oxygen sensors using a socket or wrench. Note the orientation for reinstallation.
4. Test the sensors with a multimeter to check for proper resistance and output voltage according to manufacturer specifications.
5. Replace any faulty sensors with new ones, ensuring they are compatible with the vehicle model.
6. Reconnect the wiring harness securely.

3. Inspect and Repair Exhaust System

1. Examine the exhaust for leaks or damage, focusing on the catalytic converter and joints.
2. Repair any leaks by using exhaust tape or replacing damaged sections.
3. If the catalytic converter is damaged, remove it using a socket set and replace it with a new, OEM-quality catalytic converter.
4. Torque all bolts to the manufacturer's specifications as indicated in the service manual.

4. Clear Codes and Test Drive

1. Reconnect the negative battery terminal after repairs are completed.
2. Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.
3. Test drive the vehicle for at least 20 minutes under various driving conditions to allow the system to monitor the catalytic converter’s performance.