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o2 sensors

  1. MD (2011-2016) Elantra sedan/coupe
    My check engine light turned on and using my OBD2 i got code P0420 -Catalyst system efficiency below threshold (Bank 1) . I tested my O2 sensors and they are reading fine, Sensor one is jumping between .1 and .9 while O2 sensor 2 is holding steady at around 750 (between 735 -765). The CAT temps...
  2. General Hyundai Non-Model Specific Discussion
    '05 Tuscon V6 coded a misfire in cylinder 5. It previously coded an issue with the o2 sensor in bank 1, sensor 2. I didn't have access to a live scan tool and that sensor is a pita to check with a volt meter so I checked the spark plugs first. The plugs in 1, 3, and 5 had some carbon deposits...
  3. SM (2001-2006) Santa Fe
    2003 Santa Fe, 2.4 4 cyl. I got a P0421 code recently, so I thought I'd take a look at the cat and the O2 sensors to see what was going on, if they could be cleaned, etc. This is what I found: Looks like the top substrate has completely melted. Downstream O2 sensor also looks heat...
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