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

Solution

1. Preparation

• Gather necessary tools and parts.
• Park the vehicle on a level surface and engage the parking brake.
• Disconnect the negative terminal of the battery to prevent electrical shorts.

2. Inspect and Test Oxygen Sensors

• Tools Required: OBD-II scanner, multimeter.
• Remove the upstream oxygen sensor and the downstream oxygen sensor.
• Test both sensors with a multimeter for proper voltage readings (upstream should fluctuate, downstream should remain steady).
• Replace any faulty oxygen sensors.

3. Inspect Catalytic Converter

• Tools Required: Jack and jack stands, wrench set, infrared thermometer.
• Raise the vehicle securely using jack stands.
• Inspect the catalytic converter for physical damage or signs of blockage.
• Use an infrared thermometer to compare temperatures between the upstream and downstream sides of the converter—should be a 100-200°F difference.
• If the converter is clogged or damaged, proceed to replace it.

4. Replace Catalytic Converter (if necessary)

• Tools Required: Wrench set, new gasket, new catalytic converter.
• Remove the bolts securing the catalytic converter to the exhaust system.
• Remove the old catalytic converter and gasket.
• Install the new catalytic converter with a new gasket, ensuring a tight fit.
• Torque the bolts to the manufacturer's specifications.

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 idle for a few minutes to check for any returning codes.