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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the exhaust system to cool before beginning work.

2. Inspect and Replace Oxygen Sensors

1. Locate the oxygen sensors: Identify the upstream (pre-catalytic converter) and downstream (post-catalytic converter) sensors.
2. Remove the upstream oxygen sensor:
   • Use an O2 sensor socket to unscrew the sensor.
   • Disconnect the wiring harness.
3. Install a new upstream oxygen sensor:
   • Apply anti-seize compound to the threads (if not pre-applied).
   • Torque to manufacturer specifications (usually around 30 lb-ft).
4. Repeat for the downstream oxygen sensor: Follow the same procedure as above.

3. Inspect and Replace the Catalytic Converter

1. Remove the catalytic converter:
   • Loosen the bolts or clamps securing the catalytic converter to the exhaust system.
   • Carefully detach it from the exhaust pipes.
2. Inspect the old catalytic converter: Look for signs of clogging, physical damage, or contamination.
3. Install the new catalytic converter:
   • Position the new converter in place.
   • Secure it with bolts or clamps, torquing to manufacturer specifications.

4. Reconnect Battery and Clear Codes

1. Reconnect the battery: Ensure all connections are secure.
2. Clear the error codes: Use an OBD-II scanner to erase the P0420 code and any other stored codes.