how to fix P0420 code on Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, exhaust backpressure gauge, safety goggles, gloves.
• Disconnect the battery to ensure safety while working on the vehicle.

2. Inspect and Replace Oxygen Sensors

1. Locate the oxygen sensors: Identify the upstream and downstream oxygen sensors connected to the exhaust manifold and catalytic converter.
2. Remove the oxygen sensors:
   • Use the appropriate socket to unscrew the sensors from their mounting locations.
   • Disconnect the electrical connectors carefully.
3. Install new sensors:
   • Apply anti-seize compound to the threads of the new sensors.
   • Screw in the new sensors and tighten them to the manufacturer's specifications (typically 30 Nm / 22 lb-ft).
   • Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter (if necessary)

1. Remove the exhaust components:
   • Unbolt the catalytic converter from its mounting points using a socket set.
   • If necessary, remove any heat shields or additional exhaust components obstructing access.
2. Install the new catalytic converter:
   • Position the new catalytic converter in place.
   • Torque the bolts to the manufacturer's specifications (typically 40 Nm / 30 lb-ft).
3. Reinstall any removed components:
   • Attach heat shields and other exhaust parts that were removed, ensuring all bolts are tightened securely.

4. Reconnect Battery and Clear Codes

1. Reconnect the battery terminals.
2. Use the OBD-II scanner to clear the P0420 code from the vehicle's memory.