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john -aka eauto
john -aka eauto, ASE Certified Technician
Category: Subaru
Satisfied Customers: 16302
Experience:  15 years as a auto tech
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I have a 2000 Legacy Outback wagon. Over the last year, My

Customer Question

I have a 2000 Legacy Outback wagon. Over the last year , My check engine light has been coming on. I've taken it to O'Reilly's and they told me it has p420 code. Catalytic converter below thresh hold. It has 191000 miles. I bought it used and the previous owner said he changed the o2 sensor. I don't know which one he changed. When I put premium gas in it seems to help keep the light off. Change the rear oxygen sensor? Change the converter? I plan on keeping the car forever. Put in an OEM converter? I get 24 / 25 mpg on the highway. Thank you Joe
Submitted: 1 year ago.
Category: Subaru
Expert:  john -aka eauto replied 1 year ago.

99 percent of the time on a subar a 420 code is a failed convereter

Expert:  john -aka eauto replied 1 year ago.

oe converters are expensive but they last a long time that's the best way to go

Customer: replied 1 year ago.
Can you a one that bolts in or does it need to be welded in place? While I'm at it should change any more sensors? I
Expert:  john -aka eauto replied 1 year ago.

they are bolt in new oxygen sensors should be done at the same time