Question about 1999 Ford Expedition

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Wiring diagram o2 sensor

I bought a napa ech ec98 wiring harness and do not know what wires connect to each other

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  • petertonytaz Jul 17, 2013

    it is the o2 sensor connection drivers side front before cat.



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You should have received an instruction sheet in the box with the sensor. That sheet has the color combos for the wiring for each make and model. I would contact the store and see if they have one in another box.
Each brand of sensor is different.

Posted on Jul 17, 2013

Testimonial: "i wish there was but nothing and this is normal for all parts that come from napa the rep said and they have no idea"

  • 2 more comments 
  • petertonytaz Jul 18, 2013

    i wish but no the guy that owned the truck before me pulled the whole exhaust off he cut the o2 sensor off the front drivers side and left the 3 other o2 sensor plugs

  •  Stephen
    Stephen Jul 18, 2013

    So which sensor are you trying to replace. I can get you the wiring for the factory plug but not for the NAPA sensor. You may be able to find out what brand it is such as Bosch or Nependenso.

  •  Stephen
    Stephen Jul 18, 2013

    If you can figure out the brand, you may be able to go to that website for the conversion chart.

  •  Stephen
    Stephen Jul 18, 2013

    Driver side in front of the cat would be bank 2 sensor 1. All of the O2 sensor heaters use the red wire for power and that sensor uses yellow lite blue for ground going back to the computer. The signal to the sensor is gray red and the signal return to the computer is red black.



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    Four wires (circuits) are used on each O2 sensor:

    • 12–volt feed circuit for the sensor heating element
    • Ground circuit for the heater element
    • Low-noise sensor return circuit to the PCM
    • Input circuit from the sensor back to the PCM to detect sensor operation

    O2S Sensor removal Never apply any type of grease to the oxygen sensor electrical connector, or attempt any soldering of the sensor wiring harness.
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    3. If equipped, disconnect sensor wire harness mounting clips from engine or body.
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    4. Remove O2S sensor with an oxygen sensor removal and installation tool.

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    Threads of new oxygen sensors are factory coated with anti-seize compound to aid in removal. DO NOT add any additional anti-seize compound to threads of a new oxygen sensor.
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    Hope thats help (remember comment and rated this).

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