how to fix P0420 code in Ram 1500 DT (2019-Present)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative terminal of the battery to ensure safety.
• Allow the engine to cool before starting work.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream oxygen sensor from the exhaust manifold.
  • Sub-step: Use an O2 sensor socket to avoid damaging the sensor.
• Install the new oxygen sensor and torque it to the manufacturer's specifications (typically around 30-40 ft-lbs).
• Repeat the process for the downstream oxygen sensor if necessary.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust gasket.
• Remove the exhaust pipes connected to the catalytic converter.
  • Sub-step: Mark the position of the pipes for proper alignment during reinstallation.
• Unbolt the catalytic converter from the exhaust system using a socket set.
• Install the new catalytic converter, ensuring proper alignment with exhaust pipes.
  • Sub-step: Use a new exhaust gasket to prevent leaks.
• Torque all bolts to manufacturer specifications.

4. Clear Codes and Test

• Reconnect the battery's negative terminal.
• Use the OBD-II scanner to clear the P0420 code from the system.
• Start the engine and allow it to reach operating temperature.
• Perform a test drive to ensure the check engine light does not reappear.