how to fix P0420 code in Toyota RAV4 Fourth Generation (2013-2018)

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, wrench set, multimeter, temperature probe, jack and jack stands, safety glasses, gloves.
• Allow the engine to cool before starting work. Disconnect the battery to prevent electrical shorts.

2. Inspect and Test Oxygen Sensors

• Sub-steps:
  • Locate the upstream and downstream oxygen sensors near the catalytic converter.
  • Using a multimeter, check the voltage output of both sensors (upstream should fluctuate between 0.1V and 0.9V; downstream should be more stable).
  • If either sensor is faulty, replace it with a new unit.

3. Check and Replace Catalytic Converter (if necessary)

• Sub-steps:
  • If the catalytic converter is suspected to be faulty, first check for any physical damage or clogging.
  • Remove the exhaust components using a socket set to gain access to the catalytic converter.
  • Unbolt the catalytic converter from the exhaust system (note the layout for reinstallation) and remove it.
  • Install the new catalytic converter and secure it with bolts to the exhaust system, following the manufacturer's torque specifications (usually around 25-30 lb-ft, but confirm with service manual).
  • Reconnect any oxygen sensors that were removed during the process.

4. Reassemble and Test

• Sub-steps:
  • Reconnect the battery.
  • Start the engine and allow it to reach operating temperature.
  • Use an OBD-II scanner to clear the P0420 code and monitor for any pending codes.
  • Perform a test drive to ensure the check engine light does not reappear.