how to fix P0420 on Toyota Highlander XU70 (2020-Present) for catalytic converter?

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the vehicle's negative battery terminal to ensure safety.

2. Inspect and Replace O2 Sensors

1. Remove the O2 Sensors:

   • Locate the upstream and downstream O2 sensors.
   • Use an O2 sensor socket to remove both sensors.

2. Install New O2 Sensors:

   • Apply anti-seize compound to the threads of the new O2 sensors.
   • Install the new upstream and downstream O2 sensors, tightening to the manufacturer's specifications (typically around 30 lb-ft).

3. Inspect and Replace Catalytic Converter (if needed)

1. Remove Exhaust Components:

   • Remove any brackets or hangers securing the exhaust system.
   • Use a socket set to unbolt the catalytic converter from the exhaust manifold and the exhaust pipe.

2. Install New Catalytic Converter:

   • Position the new catalytic converter in place.
   • Secure it with new gaskets and tighten the bolts to the specified torque (generally 40 lb-ft).

4. Reconnect Battery and Clear Codes

1. Reconnect the negative battery terminal.
2. Use the OBD-II scanner to clear the P0420 code from the ECU.