how to fix P0420 code on Honda CR-V Sixth Generation (2023-present)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the vehicle to cool down if the engine has been running.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, and extension.
• Remove the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors from the exhaust system.
• Inspect the connectors for damage or corrosion; replace if necessary.
• Test each sensor using a multimeter to confirm proper voltage output.
• Replace any faulty sensors with OEM or high-quality aftermarket parts.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool.
• Remove any heat shields covering the catalytic converter if applicable.
• Use the socket set to unbolt the catalytic converter from the exhaust system.
• Inspect the catalytic converter for signs of clogging or physical damage.
• Replace with a new catalytic converter that meets OEM specifications.
• Reinstall the converter and securely tighten all bolts to the manufacturer's torque specifications.

4. Reset the ECU

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code from the ECU.
• Take the vehicle for a test drive to allow the ECU to recalibrate.