why does my Ram 1500 DT (2019-Present) have a check engine light with P0420 code

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.
• Allow the vehicle to cool down before performing any work on the exhaust system.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream and downstream oxygen sensors.
2. Use an O2 sensor socket to unscrew the sensors from the exhaust system.
3. Inspect the sensors for any signs of damage or contamination.
4. Replace any faulty sensors with new, OEM-quality parts.
5. Reinstall the sensors and torque them to the manufacturer's specified values.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Assess the catalytic converter for any physical damage or blockage.
2. If replacement is needed, unbolt the catalytic converter from the exhaust system.
3. Remove any retaining brackets or supports.
4. Install the new catalytic converter, ensuring correct alignment and fit.
5. Torque the bolts to the manufacturer's specifications.

4. Clear Codes and Test

1. Reconnect the battery.
2. Use the OBD-II scanner to clear the codes from the system.
3. Start the engine and allow it to reach operating temperature.
4. Perform a test drive to monitor for any reoccurrence of the check engine light.