why is my Toyota RAV4 XA50 (2019-2024) showing a P0420 code after a new cat converter

Solution

1. Preparation

• Gather tools and parts needed for inspection and possible repairs.
• Disconnect the battery to ensure safety while working on electrical components.
• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench.

2. Inspect Exhaust System

• Step 2.1: Visually inspect the exhaust system for any signs of leaks or damage.
• Step 2.2: Use a smoke machine or soapy water to find any exhaust leaks around joints or connections.
• Step 2.3: Tighten any loose clamps or connections as necessary.

3. Check Oxygen Sensors

• Step 3.1: Locate the upstream and downstream oxygen sensors.
• Step 3.2: Disconnect the electrical connectors from both sensors.
• Step 3.3: Use a multimeter to measure the voltage output of the sensors; the upstream should fluctuate between 0.1V and 0.9V while the engine is running.
• Step 3.4: If readings are inconsistent, consider replacing the faulty oxygen sensor.

4. Catalytic Converter Verification

• Step 4.1: Confirm that the catalytic converter installed is the correct part number for the 2019-2024 RAV4.
• Step 4.2: Check the warranty and installation notes to ensure the converter was installed according to manufacturer specifications.
• Step 4.3: If necessary, re-install the catalytic converter, ensuring all gaskets are replaced and torqued to manufacturer specifications.

5. Reset the Check Engine Light

• Step 5.1: Use the OBD-II scanner to clear the P0420 code.
• Step 5.2: Reconnect the battery terminals and start the vehicle.
• Step 5.3: Allow the vehicle to reach operating temperature and check for any reoccurrence of the P0420 code.