my Toyota Highlander XU70 (2020-Present) shows a P0420 code what does it mean

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent any electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench, multimeter
• Remove the upstream oxygen sensor using the O2 sensor socket.
• Test the sensor with a multimeter to check its voltage and resistance as per specifications.
• If faulty, replace it with a new sensor, ensuring it is torqued to the manufacturer's specifications (typically around 30 ft-lbs).

3. Examine and Replace Catalytic Converter

• Tools Required: Socket set, jack and jack stands, exhaust pipe sealant
• Safely lift the vehicle using jack stands.
• Remove the exhaust pipes connected to the catalytic converter, noting the orientation for reassembly.
• Inspect the catalytic converter for any signs of physical damage or clogging.
• If damaged, remove the old catalytic converter and install a new one, ensuring to use exhaust pipe sealant on joints and torque the bolts to specification.

4. Reset the Engine Control Unit (ECU)

• Tools Required: OBD-II scanner
• After repairs, use the OBD-II scanner to clear the P0420 code from the ECU.
• Reconnect the battery.