how to fix P0420 code on my Honda CR-V Fifth Generation (2017-2022)

Solution

1. Preparation

• Gather tools and parts required.
• Ensure the vehicle is parked on a flat surface, and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, penetrating oil
• Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
• Apply penetrating oil to the threads of each sensor to ease removal.
• Disconnect the electrical connectors from both sensors.
• Use an O2 sensor socket to remove the sensors from the exhaust manifold and catalytic converter.
• Install new sensors by reversing the removal steps, ensuring connectors are firmly attached.

3. Inspect and Replace the Catalytic Converter (if necessary)

• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter or saw
• Raise the vehicle using a jack and secure it on jack stands.
• Inspect the catalytic converter for signs of damage or clogging.
• If replacement is required, detach the exhaust pipes connected to the catalytic converter using an exhaust pipe cutter.
• Remove the old catalytic converter from its mounting points.
• Install the new catalytic converter, ensuring a proper fit and alignment.
• Reconnect the exhaust pipes and secure with clamps.

4. Reset the Engine Control Module (ECM)

• Reconnect the negative battery terminal.
• Use an OBD-II scanner to clear the P0420 code from the ECM.
• Start the engine and allow it to reach operating temperature.