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

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the battery to prevent electrical issues.
• Ensure the vehicle is on a flat surface and securely raised if working underneath.

Tools Required:

• OBD-II scanner
• Torque wrench
• Socket set
• IR thermometer
• Multimeter
• Safety glasses and gloves

2. Inspect and Replace Oxygen Sensors

1. Remove the upstream oxygen sensor:
   • Locate the sensor on the exhaust manifold or downpipe.
   • Unplug the electrical connector.
   • Use a socket wrench to unscrew the sensor.
2. Install the new upstream oxygen sensor:
   • Apply anti-seize compound to the threads of the new sensor.
   • Screw it into place and tighten it to the manufacturer's specified torque.
   • Reconnect the electrical connector.
3. Repeat the process for the downstream oxygen sensor.

3. Inspect and Replace Catalytic Converter

1. Remove the old catalytic converter:
   • Disconnect the exhaust pipes at both the inlet and outlet of the catalytic converter.
   • Remove any mounting bolts using a socket wrench.
   • Carefully take out the catalytic converter.
2. Install the new catalytic converter:
   • Position the new catalytic converter in place.
   • Secure it with the mounting bolts and tighten to the specified torque.
   • Reconnect the exhaust pipes, ensuring a tight fit to avoid leaks.

4. Reset the Engine Control Module (ECM)

1. Reconnect the battery:
   • Reconnect the negative terminal of the battery.
2. Clear the diagnostic trouble codes:
   • Use the OBD-II scanner to clear the P0420 code from the ECM.