how to fix the P0420 code on my Toyota RAV4 Fifth Generation (2019-present)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Raise the vehicle securely using jack stands if access to the underside is needed.

2. Inspect and Replace Oxygen Sensors

• Remove the upstream (pre-catalytic converter) oxygen sensor:

  • Use an oxygen sensor socket and ratchet to unscrew the sensor.
  • Disconnect the electrical connector from the sensor.

• Install the new upstream oxygen sensor:

  • Apply anti-seize compound to the threads if required.
  • Hand-tighten the sensor and then use the ratchet to secure it (typically to 30 ft-lb).
  • Reconnect the electrical connector.

• Repeat the process for the downstream (post-catalytic converter) oxygen sensor if necessary.

3. Inspect and Replace Catalytic Converter (if required)

• Locate the catalytic converter and inspect for damage or clogging.
• If replacement is needed:
  • Remove the bolts securing the catalytic converter to the exhaust pipes using a socket set.
  • Disconnect any heat shields or brackets as necessary.
  • Remove the old catalytic converter.
• Install the new catalytic converter:
  • Position the new unit and secure it with the bolts.
  • Torque the bolts to manufacturer's specifications (typically around 30-40 ft-lb).
  • Reinstall any heat shields or brackets.

4. Clear Codes and Verify

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code.
• Test drive the vehicle to ensure the check engine light does not reappear.