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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Tools Required: OBD-II scanner, socket set, multimeter, torque wrench, exhaust gas temperature probe.
• Parts Required: Oxygen sensor (if needed), catalytic converter (if replacement is necessary).
• Safety Warnings: Disconnect the battery before starting work on electrical components.

2. Inspect and Replace Oxygen Sensors

1. Locate the oxygen sensors: Identify the upstream (pre-catalytic converter) and downstream (post-catalytic converter) sensors.
2. Disconnect the battery: Ensure safety while working with electrical components.
3. Remove the oxygen sensors:
   • Use a socket wrench to unscrew the sensors from their respective ports.
   • Carefully pull the connectors off the sensors.
4. Test the sensors with a multimeter to check for proper voltage and resistance according to specifications.
5. Replace faulty sensors: If any oxygen sensor is malfunctioning, install a new sensor by reversing the removal steps.

3. Inspect and Replace Catalytic Converter

1. Visual inspection: Check the catalytic converter for any signs of damage or clogging.
2. Check temperature: Use an exhaust gas temperature probe to measure inlet and outlet temperatures.
   • A significant difference may indicate a failing catalytic converter.
3. Remove the catalytic converter:
   • Loosen the bolts securing it to the exhaust system using a socket set.
   • Carefully lower the converter from its position.
4. Install a new catalytic converter:
   • Position the new converter and secure it with the appropriate bolts, ensuring a proper fit.
   • Follow the manufacturer's torque specifications for bolts.
5. Reconnect all sensors and battery: Ensure everything is in place and securely connected.