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

Solution

1. Preparation

• Gather tools: OBD-II scanner, multimeter, socket set, jack and jack stands, safety glasses, and gloves.
• Ensure the vehicle is parked on a level surface and the engine is cool.

2. Inspect and Replace O2 Sensors (if necessary)

• 2.1. Disconnect Battery

  • Disconnect the negative battery terminal to prevent electrical shorts.

• 2.2. Remove O2 Sensor(s)

  • Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) O2 sensors.
  • Use a socket or O2 sensor wrench to carefully remove the sensors.

• 2.3. Test O2 Sensors

  • Use a multimeter to test the resistance and output voltage of the sensors according to specifications.

• 2.4. Install New O2 Sensors

  • If faulty, replace with new O2 sensors, ensuring they are tightened to manufacturer specifications (usually around 30 lb-ft).

3. Inspect and Replace Catalytic Converter (if necessary)

• 3.1. Inspect for Damage

  • Check for dents, holes, or other physical damage on the catalytic converter.

• 3.2. Remove Catalytic Converter

  • If damaged, use a socket set to remove the bolts securing the catalytic converter to the exhaust system.

• 3.3. Install New Catalytic Converter

  • Install the new catalytic converter, ensuring to follow torque specifications (usually around 30 lb-ft).

• 3.4. Reconnect Exhaust System

  • Reattach any exhaust hangers or brackets that may have been removed.

4. Clear Error Codes

• Use an OBD-II scanner to clear the P0420 code from the vehicle’s ECU.
• Reconnect the battery terminal.