I have a 2015 F-150 with an EccoBoost engine that has 165K miles on it. I am receiving the check engine light with a 420 code. I just had all four O2 sensors replaced. The catalytic converter code is persistent. It will not reset. Is 165K early for the Cats to fail? Should I replace both? Bank 1 is the one that is failing. Other than this and normal wear and tear parts (brakes, shocks/struts), the truck has been great. I am hoping to get 2 more years out of it. Just curious as to what people think.

 

Welcome to the forum.

 

 

There are lots of possibilities with a P0420 Diagnostic Trouble Code (DTC).
What other DTCs do you have, P0420 does not generally cause a flashing check engine light. Provide us with the exact DTCs
How does your Engine Coolant Temperature (ECT) and/or Cylinder Head Temperature (CHT) value look? Gage should be roughly center scale or about 190F to 195F. Improper ECT and/or CHT will skew the fuel mixture and potentially cause P0420
Other possibilities

• Use of leaded fuel
• Damaged Heated Oxygen Sensors (HO2S) - look for melted wires due to contact with exhaust manifold
• Out of range Engine Coolant Temperature (ECT) and/or Cylinder Head Temperature (CHT)
• High Fuel Pressure (may not apply to your engine)
• Damaged exhaust manifold
• Damaged Catalytic converter
• Oil contamination
• Cylinder misfiring - any other codes?
• Downstream (HO2S) wires incorrectly connected
• Damage exhaust system pipe
• Damaged muffler/tailpipe assembly
• Retarded spark timing
• Leaking Fuel Injector

 

Same exact post, a week shy of 3 months later, different poster/username. Either the OP forgot their login and hasn't driven the truck since November, or someone is spamming a forum about replacing cats. Neither really make sense unless it's an AI bot trying to learn conversation.

https://www.f150forum.com/f2/catalyt...cement-579933/

 

This is all the info about the OP:

• About castro8Country of ResidenceATGenderMale
  
  The only country that uses AT that I could find is Austria.

 

castro8,

It’s been a couple of weeks since you last posted. Have you resolved this issue and if so, please post the solution? Feedback is important so that we all learn solution paths to these issues.

Thanks in advance

Jimboy

 

I have 162k and was getting the p420, I used the defoulers about 2 months ago that are posted in #3 above and it has not returned,

 

The op has not responded, but the excellent list of P0420/430 checks makes me want to post here anyway. (Thanks, JimBoy, for trying to contact the op.)

As my contribution to the topic, here goes:

My 2018, F150, 3.3l, XL, non-turbo or raptor, has the above cel’s. 196,000 miles.

I researched cheap catalytic converters in another thread but took someone’s advice and decided to get the whole situation diagnosed here in Wilmington NC. The list of possible factors is long as the great list above points out. My trusted local shop took my truck overnight for $100+ and will let me know today.

The truck runs great. I have had it almost a year now. My first big truck and I have been very happy. (KOW, KOW)

I will share my results with yall later.

 

Where in Wilmington? I'm in Raleigh and am looking for a shop that can do this a reasonable price.