code 174 Heated O2 sensor

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by cwgburban, Apr 17, 2010.

  1. cwgburban

    cwgburban New Member

    Great info on the site, on heated O2 sensors which code 174 is about.
    My diagnostic, PO174 says failed heated oxygen sensor, Bank 2 sensor 1.

    What side is Bank 2? Is this sensor before the cat converter?

    2003 Suburban 4X4 1500
  2. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    Bank 2 is passenger side and sensor 1 is before cat.
  3. vncj96

    vncj96 Epic Member 5+ Years 1000 Posts

    Just make sure you actually get the passanger side pipe, they do cross around underneath a little, but yes position 1 is pre cat and position 2 is post cat
  4. MrShorty

    MrShorty Epic Member Staff Member 5+ Years 1000 Posts

    If I may, I would like to clarify what your diagnostic is really saying. In general, there are no trouble codes for "part x has failed." My code list defines P0174 as "fuel trim too lean bank 2." The computer is using the O2 sensor signal to optimize the air/fuel (A/F) mixture. When this code is set, it is saying, "No matter how much fuel I tell the injectors to dump into that bank of the engine, I can't get the O2 sensor signal for that side to read normal." Certainly, this could be due to a faulty O2 sensor, but there are other possibilities as well (a vacuum leak or loose electrical connection, for example).

    Your strategy for diagnosing these things depends on you. Some prefer to troubleshoot by the book, which means not replacing anything until they feel like they've found the real cause of the code. Others, especially with O2 sensor codes, prefer to replace the O2 sensor as a "guess," and, if that doesn't resolve the issue, then go through the more detailed process of diagnosing the real fault.

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