P0154 mil - Code Check

Discussion in 'GM Powertrain' started by Deadkennedys29, Jan 13, 2011.

  1. Got a p0154 No circuit No activity code, light on.. and sometimes the truck feels like its stuttering.. also got random misfire codes. ive been searching around and the general idea is.. replace O2 sensors and check wiring... what do you guys think?

    99'HEARTBEAT MODERATOR Staff Member 5+ Years ROTM Winner 1000 Posts Platinum Contributor

    For Trouble Code.....P0154......Symptoms of a P0154 code may include:

    • MIL (Malfunction Indicator Lamp) illumination
    • Other codes indicating rich or lean condition may be present
    • Poor idle, won't idle
    • Misfire at idle or at highway speed
    • Engine may blow black smoke at tailpipe
    • Fuel economy may decrease
    • May start and stall

    Potential causes of a P0154 code include:

    • Faulty bank 2,1 Oxygen sensor
    • Holes in exhaust near oxygen sensor
    • Short to voltage or ground on signal circuit
    • Open or high resistance in signal circuit
    • Wiring harness chafing/rubbing on exhaust components
    • Water/oil intrusion at O2 sensor connector
    • Broken lock or loose terminals on O2 sensor connector
    • Oil/coolant fouled oxygen sensor
    Possible Solutions

    First start the engine and bring it up to operating temperature and ensure the engine reaches closed loop. Then, using the live data function on a scan tool, observe the Bank 2,1 oxygen sensor voltage reading. Is it switching properly? If so, the problem may be an intermittently bad sensor or more likely a wiring problem. Visually check the O2 sensor wiring and repair as needed. Does the voltage for the Bank 2,1 oxygen sensor appear to be "stuck" and not moving? If so, increase idle speed for 30 seconds or so. If the sensor begins switching after a period of elevated idle, visually check the exhaust for holes or rust near the O2 sensor that could be affecting the voltage reading.
  3. mosntersurban

    mosntersurban New Member

    P0154 refers to the right side front (upstream) O2 sensor or wiring if the on board computer is functioning.

    Presuming that most of us (me) do not have testing equipment. I suggest switching the left front 02 sensor with the right front 02 sensor. All you need is an open end wrench and 15 minutes. Then zero your codes (by disconnecting the battery for about an hour - like I did) then driving until the engine light comes back on. (if they never do come back on, it was only a bad connection).

    If the light comes on, then get the codes read again.

    If it reads P0134 (left side front), then you know it is the 02 sensor.

    If it still reads P0154 you have eliminated the 02 sensor as the problem, and saved $50. Now check the coupling, the wiring, ground, heater wire and signal wires. If all that is good check the PCM (that is over my ability).
  4. hey guys, thanks for the replies. its been a while so here's how it played out.

    Before i even got a chance to try what y'all had suggested i noticed my truck was drinking tons of dexcool & creating white clouds behind me LOL. Took it to my shop and it started as a blow head gasket.. Then bad heads.. and then a cracked engine block.

    she's still awaiting a new engine but its in the works.

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