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p0420

  1. Engine & Drivetrain
    Hey all, Not a car guy and may post this a few different places so please forgive me if I leave out something pertinent or you see this posted somewhere else.. So I have a 2005 Subaru Outback 2.5L Limited, the CEL is on and is for the P0420 code. This is the only code the car is throwing. It...
  2. Engine & Drivetrain
    Hi everyone I took my 2003 outback into my usual mechanic for P0420 codes and he replaced the Catalytic Converter. Check Engine light came back on only two days after, so I ran the codes and got P0420 again. I cleared them and chalked it up to the new CC needing a few days. I am not noticing...
  3. Problems & DIY Maintenance
    I have had the P0420 code intermittently popping up over the past year or two. Earlier this year I noticed my gas mileage starting to get worse, and I am not sitting at 12/20 while it used to be at 18/27. I have replaced both upstream O2 sensors, and a read one that was showing weird voltages...
  4. Gen 3: 2005-2009
    Hi friends, I recently had my first run-in with the infamous P0420 code (Catalyst System Efficiency Below Threshold) on my 2006 Outback 2.5 Limited. The CEL has been on with the P0420 code for probably about a month now. At first, it was intermittent and would sometimes go off on its own (I...
  5. Gen 3: 2005-2009
    Hello, I am new to this style of forums, but I am determined that others are the best way to resolve my problems with my new Subaru. Here is the backstory: Bought a 2005 Subaru legacy Limited 2.5gt wagon Tuesday, 11/12/19, I test drove it, felt smooth, fast, very clean car no lights or issues...
  6. Gen 3: 2005-2009
    I’m sure I’m asking a question that is already out there but I’m not finding it. I have an 05 base model California exhaust. I have a P0420 code that I’m going to replace the O2 sensors first before I replace the catalytic coverts to see if that corrects the CEL. Under the car I have the 2 up...
  7. Problems & DIY Maintenance
    Hi all, first time poster, thanks in advance for your collective wisdom. 2006 2.5L 5speed Outback Test group: 6FJXX02.5NVD Been driving with the MIL on for the last 3 months, ignoring the P0420 I've been getting. As of yesterday, can barely make it up hills on the freeway, so I think the time...
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