my Honda CR-V has a check engine light and code P0420, what should I do?

Solution

1. Preparation

• Gather tools and parts for the repair.
• Disconnect the negative battery terminal to prevent electrical issues.
• Allow the engine to cool before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

1. Remove the Old Oxygen Sensors

   • Use an oxygen sensor socket to remove the upstream and downstream oxygen sensors from the exhaust system.
   • Inspect the sensors for any signs of damage or contamination.

2. Install New Oxygen Sensors

   • Apply anti-seize compound on the threads of the new oxygen sensors.
   • Install the upstream sensor first, followed by the downstream sensor, tightening them to the manufacturer's specifications (usually around 30 ft-lbs).

3. Inspect and Replace the Catalytic Converter

1. Remove Exhaust Components

   • If necessary, remove any heat shields or pipes obstructing access to the catalytic converter.
   • Use a socket set to unbolt the catalytic converter from the exhaust system.

2. Install New Catalytic Converter

   • Position the new catalytic converter and secure it with the bolts, ensuring proper alignment.
   • Torque the bolts to the manufacturer's specifications (typically around 25-35 ft-lbs).

4. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the trouble codes from the vehicle’s memory.

5. Test Drive

• Start the engine and let it idle for a few minutes.
• Take the vehicle for a test drive to ensure that the check engine light does not reappear.