how to fix P0420 code on my Toyota Corolla E210 (2019-2024)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to prevent any electrical shorts during the repair process.

Tools Required:

• OBD-II scanner
• Multimeter
• Socket set
• Torque wrench
• Oxygen sensor socket
• Safety goggles
• Gloves

2. Inspect and Replace Oxygen Sensors

1. Remove the upstream oxygen sensor:
   • Locate the upstream oxygen sensor (before the catalytic converter).
   • Use an oxygen sensor socket to carefully unscrew the sensor.
2. Test the oxygen sensor:
   • Use a multimeter to check the voltage output; it should fluctuate between 0.1 to 0.9 volts. Replace the sensor if readings are outside this range.
3. Install a new oxygen sensor:
   • Apply anti-seize compound to the threads of the new oxygen sensor.
   • Install the new oxygen sensor and torque it to the manufacturer's specification (usually around 30-40 ft-lbs).

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

1. Remove the catalytic converter:
   • Loosen and remove any bolts or nuts securing the catalytic converter to the exhaust system using a socket set.
   • Carefully detach the catalytic converter from the exhaust system.
2. Inspect the catalytic converter:
   • Check for physical damage, excessive carbon buildup, or blockage. If damaged, proceed to replace.
3. Install a new catalytic converter:
   • Position the new catalytic converter in place and secure it with the original or new hardware.
   • Torque the bolts to the manufacturer’s specifications (usually around 25-35 ft-lbs).

4. Final Checks

• Reconnect the battery.
• Clear the codes using the OBD-II scanner.
• Start the engine and allow it to reach operating temperature.