how to fix P0420 code on Toyota Camry Eighth Generation (2018-present)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shock.

2. Inspect and Replace Oxygen Sensors

1. Remove Upstream Oxygen Sensor:

   • Use an oxygen sensor socket to carefully unscrew the upstream sensor.
   • Disconnect the wiring harness from the sensor.

2. Install New Upstream Oxygen Sensor:

   • Apply anti-seize compound to the threads of the new sensor.
   • Screw in the new sensor and reconnect the wiring harness.
   • Torque to the manufacturer’s specifications (typically 30-40 Nm).

3. Repeat for Downstream Oxygen Sensor (if needed):

   • Follow the same steps to inspect and replace the downstream oxygen sensor if it is faulty.

3. Inspect and Replace Catalytic Converter

1. Remove Exhaust Components:

   • Unbolt any exhaust hangers and remove the exhaust pipe connected to the catalytic converter using a socket set.
   • Remove bolts securing the catalytic converter to the exhaust manifold.

2. Install New Catalytic Converter:

   • Position the new catalytic converter and secure it to the exhaust manifold and exhaust pipe using new gaskets and bolts.
   • Torque all bolts to the manufacturer’s specifications.

3. Reattach Exhaust Components:

   • Reinstall any exhaust hangers and ensure that all connections are tight.

4. Reset Engine Control Unit (ECU)

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

Tools Required:

• OBD-II scanner
• Oxygen sensor socket
• Socket set
• Torque wrench
• Anti-seize compound

Parts Required:

• New upstream oxygen sensor
• New downstream oxygen sensor (if necessary)
• New catalytic converter (if necessary)
• Exhaust gaskets

Estimated Repair Time: 2-4 hours

Safety Warnings:

• Allow the exhaust system to cool before working on it to avoid burns.
• Ensure proper ventilation when working under the vehicle.