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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Inspect Oxygen Sensors

• Tools Required: OBD-II scanner, multimeter
• Use the OBD-II scanner to monitor live data from the oxygen sensors.
• Check voltage readings: the upstream sensor should fluctuate between 0.1 to 0.9 volts, while the downstream sensor should be more stable.
• If the readings are out of range, replace the faulty oxygen sensors.

3. Check and Repair Exhaust Leaks

• Tools Required: Socket set, exhaust sealant or clamps
• Inspect the exhaust system for any leaks, particularly around joints and the catalytic converter.
• If leaks are found, repair them using exhaust sealant or replace any damaged clamps or gaskets.

4. Replace the Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench
• Remove the exhaust bolts securing the catalytic converter.
• Carefully remove the old catalytic converter from the exhaust system.
• Install the new catalytic converter, ensuring it is properly aligned.
• Torque the exhaust bolts to the manufacturer's specifications (typically around 30-40 ft-lbs).

5. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code.
• Start the engine and allow it to reach operating temperature.