how to fix the P0420 code on my Toyota RAV4 XA50 (2019-2024)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety during work on electrical components.
• Raise the vehicle securely using jack stands.

2. Inspect Oxygen Sensors

• Tools Required: OBD-II scanner, multimeter
• Remove the upstream (pre-catalytic) oxygen sensor from the exhaust manifold.
• Test the sensor's operation by measuring the voltage output while the engine is running; it should fluctuate between 0.1V and 0.9V.
• If faulty, replace the oxygen sensor with a compatible part.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if necessary)
• Remove the downstream (post-catalytic) oxygen sensor if applicable.
• Unbolt the catalytic converter from the exhaust system; if it’s welded, use an exhaust cutter to remove it.
• Inspect the old catalytic converter for signs of clogging or damage.
• Install the new catalytic converter, ensuring proper alignment with exhaust flanges.
• Torque the bolts to the manufacturer's specifications (typically around 25-30 ft-lbs, but check the service manual for exact values).
• Reinstall the downstream oxygen sensor.

4. Clear Codes and Test

• Tools Required: OBD-II scanner
• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code from the vehicle’s system.
• Start the engine and take the vehicle for a test drive to ensure the code does not return.