Honda CR-V Sixth Generation (2023-present) check engine light P0420 code how to fix

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative terminal of the battery to prevent electrical shorts.
• Allow the engine to cool before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors. The upstream sensor is before the catalytic converter, and the downstream sensor is after it.
  2. Using an O2 sensor socket, carefully unscrew and remove the faulty sensors.
  3. Install the new oxygen sensors, ensuring they are tightened to the manufacturer’s specifications (typically around 30 lb-ft).
  4. Reconnect the electrical connectors for each sensor.

3. Inspect and Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Remove the exhaust pipe bolts connecting to the catalytic converter using a socket set.
  2. Carefully detach the catalytic converter from the exhaust system.
  3. Inspect the exhaust flow through the catalytic converter by looking for any signs of blockage; if blocked or damaged, replace with a new catalytic converter.
  4. Install the new catalytic converter, ensuring proper alignment and sealing.
  5. Tighten all bolts to the manufacturer’s torque specifications (typically around 40 lb-ft).

4. Clear Diagnostic Codes

• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.
  3. Start the engine and allow it to reach operating temperature while monitoring for any reoccurrence of the check engine light.