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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle battery.
• Ensure the vehicle is on a level surface and secure it with wheel chocks.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream oxygen sensor (O2 sensor before the catalytic converter).
  • Use the O2 sensor socket to unscrew it from the exhaust manifold.
• Install the new upstream O2 sensor.
  • Torque to manufacturer specifications (usually around 30 ft-lbs).
• Repeat the process for the downstream O2 sensor (O2 sensor after the catalytic converter) if necessary.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, jack stands, cutting tool (if applicable).
• If the catalytic converter is damaged or not functioning:
  • Raise the vehicle and secure it with jack stands.
  • Remove any mounting bolts and exhaust hangers securing the catalytic converter.
  • Cut the exhaust pipes if necessary.
• Install the new catalytic converter.
  • Ensure proper alignment and secure it with bolts and hangers to the manufacturer’s torque specifications.

4. Check for Exhaust Leaks

• Inspect all exhaust connections and gaskets for leaks.
• Replace any damaged gaskets or seals to ensure a tight fit.

5. Reconnect Battery and Clear Codes

• Reconnect the battery terminal.
• Use the OBD-II scanner to clear the P0420 code from the ECU.
• Start the engine and allow it to reach operating temperature.