what does error code P0420 mean for my Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle's battery to ensure safety while working on the electrical components.

2. Inspect Oxygen Sensors

• Tools Required: OBD-II scanner, multimeter, socket set.
• Remove the upstream and downstream oxygen sensors.
• Check the resistance and voltage output of the sensors using the multimeter. Compare readings to manufacturer specifications.
• If any sensor is faulty, replace it with a new one.

3. Inspect Catalytic Converter

• Tools Required: Wrench or socket set, flashlight.
• Visually inspect the catalytic converter for signs of physical damage, such as dents or cracks.
• If the converter is damaged or blocked, it will need to be replaced.

4. Replace Catalytic Converter (if necessary)

• Tools Required: Wrench or socket set, exhaust gasket, possibly a torch for stubborn bolts.
• Remove the exhaust pipes connected to the catalytic converter.
• Remove the old catalytic converter from its mounting brackets.
• Install the new catalytic converter, ensuring proper alignment.
• Reconnect the exhaust pipes and tighten all bolts to manufacturer specifications.

5. Reset the ECU

• Reconnect the vehicle's battery.
• Use the OBD-II scanner to clear the P0420 error code and reset the vehicle’s ECU.