Honda CR-V Fifth Generation (2017-2022) check engine light on with code P0420, what to do?

Solution

1. Preparation

• Ensure the vehicle is parked on a flat, stable surface.
• Disconnect the negative battery terminal to prevent electrical shocks.
• Gather all necessary tools and parts.

2. Inspect and Replace Oxygen Sensors

1. Remove the upstream oxygen sensor:
   • Locate the upstream oxygen sensor (typically near the exhaust manifold).
   • Use an oxygen sensor socket to unscrew and remove the sensor.
2. Install the new upstream oxygen sensor:
   • Apply anti-seize compound to the threads of the new sensor (if applicable).
   • Install the new sensor and tighten it to the manufacturer’s specifications (usually around 30 lb-ft).
3. Repeat for the downstream oxygen sensor:
   • Locate and remove the downstream oxygen sensor in the same manner.
   • Install the new downstream sensor, applying anti-seize compound and tightening to specifications.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Remove the exhaust system components:
   • If the catalytic converter shows signs of damage, disconnect the exhaust pipes at the flanges using a socket set.
   • Support the exhaust system to prevent strain on the hangers.
2. Remove the catalytic converter:
   • Unbolt or cut the clamps securing the catalytic converter to the exhaust system.
3. Install the new catalytic converter:
   • Position the new catalytic converter in place, ensuring proper alignment with exhaust pipes.
   • Secure it with new gaskets and bolts, tightening to the specified torque (usually 30-40 lb-ft).
4. Reinstall any removed components:
   • Reattach any exhaust hangers or components that were removed.

4. Clear Codes and Test

1. Reconnect the battery:
   • Reconnect the negative battery terminal securely.
2. Clear the trouble codes:
   • Use the OBD-II scanner to clear the P0420 code.
3. Test drive the vehicle:
   • Drive the vehicle for a short distance to ensure the check engine light does not return.