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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the battery before starting any repairs to avoid electrical issues.

2. Inspect and Replace Oxygen Sensors

1. Remove the downstream oxygen sensor:
   • Use an oxygen sensor socket to unscrew the sensor from the exhaust pipe.
   • Disconnect the electrical connector.
2. Install the new downstream oxygen sensor:
   • Apply anti-seize compound to the threads of the new sensor (if applicable).
   • Connect the electrical connector and screw the sensor into place, tightening to the manufacturer's specifications (usually about 30 lb-ft).
3. Repeat for the upstream oxygen sensor if necessary:
   • Follow the same steps as above for the upstream sensor.

3. Inspect and Replace Catalytic Converter (if needed)

1. Remove the exhaust components:
   • Loosen and remove any bolts or clamps securing the catalytic converter to the exhaust system.
   • Use a socket set and wrench to detach the connections.
2. Inspect the catalytic converter:
   • Check for physical damage or excessive carbon buildup.
3. Install the new catalytic converter:
   • Position the new converter in place and secure it with bolts or clamps.
   • Follow the manufacturer’s torque specifications (typically around 40 lb-ft).
4. Reattach any remaining exhaust components:
   • Ensure all connections are tight and leak-free.

4. Reset the Engine Control Module (ECM)

1. Reconnect the battery:
   • Ensure all tools are removed from the engine bay.
   • Reconnect the battery terminals, starting with the positive terminal first.
2. Clear the trouble codes:
   • Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.