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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the vehicle battery to avoid electrical issues during repairs.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Sub-steps:
  1. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  2. Remove the upstream oxygen sensor using the O2 sensor socket and ratchet.
  3. Install the new upstream oxygen sensor and torque to manufacturer specifications (usually around 30-50 lb-ft).
  4. Repeat for the downstream oxygen sensor if it's also faulty.

3. Inspect and Replace Catalytic Converter

• Tools Required: Wrench set, socket set, torch (if necessary for rusted bolts), new gaskets
• Sub-steps:
  1. Raise the vehicle securely on jack stands.
  2. Remove the bolts securing the catalytic converter to the exhaust system using the socket set. If bolts are rusted, use a torch to heat them before attempting to remove.
  3. Replace any gaskets as necessary to prevent exhaust leaks.
  4. Install the new catalytic converter, ensuring it is aligned properly with the exhaust system and tighten bolts to the manufacturer's torque specifications (check manual for exact values).
  5. Reconnect any exhaust hangers or supports that were disconnected during the removal.

4. Reconnect Battery and Clear Codes

• Reconnect the battery and use the OBD-II scanner to clear the P0420 code from the vehicle's computer.