how to fix P0420 code on my Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, jack and jack stands.
• Clear the P0420 code from the vehicle's computer using the OBD-II scanner before starting repairs.
• Ensure the vehicle is parked on a flat surface and the engine is cool.

2. Inspect and Replace Oxygen Sensors

• Step 1: Disconnect the battery to prevent electrical shorts.
• Step 2: Locate the upstream and downstream oxygen sensors (usually found before and after the catalytic converter).
• Step 3: Use a socket wrench to remove the sensors from their respective positions.
• Step 4: Install the new oxygen sensors and torque to manufacturer's specifications (typically around 30-35 ft-lbs).
• Step 5: Reconnect the battery.

3. Inspect Catalytic Converter

• Step 1: Raise the vehicle using a jack and secure it with jack stands.
• Step 2: Visually examine the catalytic converter for any signs of damage, such as dents or holes.
• Step 3: If the catalytic converter appears damaged or carbon-fouled, remove it using a socket wrench.
• Step 4: Install a new catalytic converter, ensuring proper alignment with exhaust pipes.
• Step 5: Torque the bolts to the specified value (usually around 25-30 ft-lbs).

4. Final Checks

• Step 1: Reconnect any connectors and sensors removed during the process.
• Step 2: Start the engine and let it idle for a few minutes to check for leaks or irregular sounds.
• Step 3: Take the vehicle for a test drive to ensure the engine runs smoothly and the check engine light remains off.