P0420

[mach8274]

Anyone run into a P0420 on theirs? Mine is a 2016 with only 20k miles on it. Hard to believe the cat is bad already but I guess anything is possible. Any advice is appreciated.

[Perblue]

I doubt it's the cat......unless it's missing or someone stole it. It could be any of these things.

 

• Damaged muffler or leaks in the muffler.
• Damaged exhaust manifold or leaks in the exhaust manifold.
• Damaged exhaust pipe or exhaust pipe leaks.
• A misfire in the engine.
• Oil contamination in catalytic converter.
• Faulty catalytic converter (most common).
• Faulty engine coolant temperature sensor.
• Faulty front oxygen sensor.
• Faulty rear oxygen sensor.
• Damaged oxygen sensor wiring.
• Oxygen sensor wiring that is not properly connected.
• Damaged oxygen sensor connectors
• A leaking fuel injector.
• High fuel pressure.
• Use of the wrong kind of fuel (using leaded fuel instead of unleaded fuel)

[WWWPerfA_ZN0W]

20k miles on a 2016 is very low average mileage per year.  even with the name "ecoboost", you cannot really avoid the reality of short tripping, idling, city vs hwy traffic, etc.

 

it is very likely that fuel has been dumping into the catalytic converter the whole time, because of these "special operating conditions".  would advise, at minimum,

1. changing engine oil regularly, every 6 mo or 5K miles max, with a full synthetic
2. changing spark plugs regularly, every 5 years or 60k miles max
3. using a GDI fuel system cleaner that you put in the fuel tanks
4. cleaning sensors such as the MAP and IAT
5. changing ALL fluids asap, as an extra step.

once you get to a properly conditioned engine, you may see the P code disappear.  hopefully not too late.