why does my Honda CR-V keep throwing P0420 code

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery cable to prevent electrical shorts.

Tools Required:

• OBD-II scanner
• Multimeter
• Socket set
• Torque wrench
• Backpressure gauge

2. Inspect and Replace Oxygen Sensors

• Step 1: Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
• Step 2: Disconnect the electrical connectors for both sensors.
• Step 3: Use a socket to remove the sensors from the exhaust system.
• Step 4: Install the new oxygen sensors and torque them to the manufacturer's specification (usually around 30-40 ft-lbs).
• Step 5: Reconnect the electrical connectors ensuring a secure fit.

3. Examine and Replace Catalytic Converter (if necessary)

• Step 1: If backpressure test indicates a blockage, remove the catalytic converter.
• Step 2: Use a socket set to disconnect the exhaust pipes from the catalytic converter.
• Step 3: Install the new catalytic converter, ensuring it aligns properly with exhaust flanges.
• Step 4: Torque all bolts to the specified value (usually around 30-40 ft-lbs).
• Step 5: Reconnect any heat shields or additional components removed during the procedure.

4. Clear Codes and Test Drive

• Step 1: Reconnect the negative battery cable.
• Step 2: Use the OBD-II scanner to clear the P0420 code from the system.
• Step 3: Start the vehicle and allow it to reach operating temperature.
• Step 4: Take the vehicle for a test drive to ensure the issue is resolved.