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2015 - Chevy SONIC LTZ


Topic starter

Brand: Chevy 


Year: 2015

Trans: Automatic (CVT) FWD


Vin: 1G1JE6SB8F4124454


I recently had a Check Engine light on, so, I plugged in my OBDII scanner and it said "P0420" with the following " Catalyst System Efficiency Below Threshold Bank 1"

I asked a mechanic who doesn't work for the dealer about this and i was told i need a new Catalytic Converter, BUT, because of my milage I can get a replacement at the dealer since its still covered under warranty.

I went to the dealer and was told that my Exhaust Flex Pipe is leaking and that they can not replace the cat. unless "I" replace the Flex Pipe. OK, so they quoted me $799, I, instead went elsewhere and replaced the Flex Pipe along with a Downstream Ox. sensor for LESS then that! - Doing so fixed my Check Engine light.

I returned to the dealership a couple days later and told them "OK, I fixed the Flex pipe" and then I requested a NEW Catalytic Converter. They responded saying "well since the Check Engine light is off now, we can't replace the cat. because the problem wasn't the cat." I responded clearly upset "well, i still want a new cat." i was told no, they cant just replace it if its not broken. 

My question to you car professionals out there is... can they do that? can they just say no? to a repair that i want? regardless of which i need it or not? - What is some helpful advice for the future? (If im wrong then I'll accept that) 

I mean...

hypothetically if i walked into the dealer and said "hello sir i want 4 new tires" and they say " your tires dont need to be replaced they have plenty of tread left" and I say "i dont care I want new tires" - Im sure they would just shrug their shoulders, take my money and say OK 4 new tires it is.

Is this principal not the same for me and my cat.? I still want a new Cat. (If I'm wrong then I'll accept that) 



1 Answer

I’m with the dealer in this one. It is very rare that the cat goes bad in this mileage and since you had exhaust leak, odds are that the cat was fine.  I’m sorry to say this, but you want to replace it under warranty and you don’t have a solid proof that the cat is the issue. 

Thanks, I appreciate the reply.