how to fix P0420 code on Toyota Camry XV70 (2018-2024)

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, jack stands, safety glasses, gloves.
• Ensure the vehicle is parked on a flat surface, and the engine is cool. Disconnect the battery to avoid electrical shocks.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream and downstream oxygen sensors (usually found before and after the catalytic converter).
2. Use the OBD-II scanner to check the operation of the sensors; compare the voltage readings.
3. If readings are out of spec, proceed to replace the affected oxygen sensor(s):
   • Unplug the electrical connector.
   • Use a socket to remove the sensor.
   • Apply anti-seize compound on the threads of the new sensor.
   • Install the new sensor and torque it to the manufacturer’s specifications (usually around 30 ft-lbs).
   • Reconnect the electrical connector.

3. Inspect and Replace Catalytic Converter (if needed)

1. If the oxygen sensors are functioning properly, proceed to examine the catalytic converter.
2. If physical damage or clogging is evident:
   • Remove the exhaust pipes connected to the catalytic converter using a socket set.
   • Remove the catalytic converter by unbolting it from its mounts. Note the orientation for reinstallation.
   • Install the new catalytic converter, ensuring proper alignment.
   • Torque the bolts to manufacturer specifications (typically around 40-50 ft-lbs).
   • Reconnect the exhaust pipes and check for leaks.

4. Clear Codes and Test Drive

1. Reconnect the battery.
2. Use the OBD-II scanner to clear the P0420 code.
3. Perform a test drive to ensure the check engine light does not reappear and monitor performance.