my Honda CR-V has a check engine light with code P0420 what does that mean

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, exhaust pressure gauge.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Replace Oxygen Sensors

1. Locate the oxygen sensors: Identify the pre-catalytic and post-catalytic oxygen sensors.
2. Disconnect the sensors: Unplug the electrical connectors from the sensors.
3. Remove the sensors: Use a socket set to unscrew the sensors from the exhaust system.
4. Install new sensors: Apply anti-seize compound to the threads of the new sensors, screw them in by hand, and then tighten to manufacturer specifications (typically around 30-40 ft-lbs).
5. Reconnect the sensors: Plug the electrical connectors back into their respective sensors.

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

1. Remove the exhaust system components: If no other issues are found and the catalytic converter is damaged, unbolt the exhaust pipe from the catalytic converter using a socket set.
2. Remove the catalytic converter: Carefully detach the catalytic converter from the exhaust manifold and the downstream exhaust pipe.
3. Install new catalytic converter: Position the new catalytic converter in place, ensuring the gaskets are properly aligned. Secure it with the bolts and torque them to manufacturer specifications (usually around 30-35 ft-lbs).
4. Reinstall the exhaust system components: Reattach any pipes or heat shields that were removed, ensuring a tight seal.

4. Reset the Engine Control Module (ECM)

1. Reconnect the battery: Reattach the battery terminals securely.
2. Clear the codes: Use the OBD-II scanner to clear any existing codes.
3. Start the engine: Allow it to reach operating temperature and check for the check engine light.