how to fix P0420 code on Genesis G70 IG (2017-2023)

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 negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

1. Locate the Oxygen Sensors: Identify the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
2. Remove the Sensors: Use an oxygen sensor socket to carefully unscrew the sensors from their respective locations.
3. Inspect the Sensors: Check for signs of damage or contamination on the sensor tips.
4. Install New Sensors: Apply anti-seize compound to the threads of the new sensors and install them, tightening to the manufacturer’s specifications (typically 30 lb-ft).

3. Examine the Catalytic Converter

1. Inspect for Damage: Check the catalytic converter for physical damage, such as dents or cracks.
2. Perform a Backpressure Test: Use a backpressure gauge to check for excessive backpressure which may indicate a clogged converter.
3. Replace the Catalytic Converter: If damaged or clogged, remove the catalytic converter by unbolting it from the exhaust system and install a new one, ensuring proper alignment and securing with the appropriate bolts and gaskets.

4. Check Exhaust System

1. Inspect for Leaks: Examine the entire exhaust system for leaks using a smoke machine or by visually inspecting joints and welds.
2. Repair Leaks: Seal any leaks found using appropriate exhaust sealant or by replacing damaged sections of the exhaust pipe.

5. Clear Codes and Test

1. Reconnect Battery: Reconnect the negative battery terminal.
2. Clear the Codes: Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
3. Test Drive: Take the vehicle for a test drive under various conditions to ensure no codes reappear and that performance is restored.