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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety during the repair.
• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, exhaust temperature probe.

2. Inspect and Replace Oxygen Sensors

• Locate the upstream and downstream oxygen sensors.
• Use a socket wrench to remove the old sensors.
• Inspect the connectors for corrosion and clean if necessary.
• Install new oxygen sensors, ensuring they are tightened to the manufacturer’s torque specifications (typically around 30 lb-ft).
• Reconnect the battery.

3. Replace the Catalytic Converter

• Raise the vehicle securely on jack stands.
• Use a socket set to remove the exhaust pipes connected to the catalytic converter.
• Unbolt the catalytic converter from its mounting brackets and remove it from the exhaust system.
• Install the new catalytic converter, ensuring proper alignment with the exhaust pipes and secure it with bolts.
• Reattach exhaust pipes and tighten all connections to manufacturer specifications.

4. Clear Codes and Test

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code.
• Start the engine and let it idle for a few minutes to ensure proper operation.
• Take the vehicle for a test drive to check for any reoccurrence of the check engine light.