Bank 1, sensor 1 oxygen sensor

Tiny
FENDER1
  • MEMBER
  • 1999 FORD EXPLORER
Six cylinder four wheel drive automatic 174,000 miles.

My check engine light just recently came on. I ran the codes and it turns out to be my O2 sensor (bank 1, sensor 1). I have the 4.0 SOHC. Is this sensor located on the passenger side of the vehicle in front of the converter? And if so, can this be changed without having the car on a lift? Thank you.
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Friday, February 20th, 2009 AT 8:43 AM

8 Replies

Tiny
BLACKOP555
  • EXPERT
You are correct with the location of the o2 sensor.

It should be easy to get to it if you can get under the vehicle.
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Sunday, February 22nd, 2009 AT 4:22 PM
Tiny
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Thank you for your response. I was able to slide under the vehicle relatively easy and found the sensor without any problems. What should have been a twenty minute job turned into almost two hours. Getting to the O2 sensor and putting a short 7/8 Inch wrench on it was the easy part. It was the wiring harness that was located the full length of the wiring harness straight up and between the bell housing and the body. I was finally able to reach it using a twelve inch thin screwdriver to depress the harness clip and gently pull the wires down.

Putting the new clip in was the easy part?

Thanks again!
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Monday, February 23rd, 2009 AT 10:23 AM
Tiny
BLACKOP555
  • EXPERT
Yeah, I am not a big fan of that set up. But they do prevent the wires from melting on the hot exhaust!

I hope you put anti-seize compound on the threads, that way it will not seize up on you.

A lot of people cut the sensors wiring harness and splice in the new one, but unless you solder it and heat shrink it it will rust and mess with the sensor readings.

Also, examine the old o2 sensor for signs of damage or white/green flaky stuff for indications of why it went out.
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Monday, February 23rd, 2009 AT 10:22 PM
Tiny
FENDER1
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Luckily the new sensor that I bought (from Ford) came with the anti-seize on the threads.

The old sensor did not look too bad when I removed it. The code indicated that the heating element inside of the sensor had gone bad. I had read that sometimes people had luck by just pulling the harness and then reinserting, but with 174,000 on the car and this being the original sensor, spending $110.00 at the dealer for a new sensor just seemed to be the way to go. Hopefully the other three do not go out anytime soon, especially with each sensor costing that much.
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Tuesday, February 24th, 2009 AT 8:16 AM
Tiny
BLACKOP555
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If that sensor was misreading even due to old age it might not have thrown a lean code.

Also, it could have been robbing you of precious gas mileage. Replacing it at $110.00 for the part could easily save you more then that if it was misreading and hampering your performance.

That was a smart move!
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Tuesday, February 24th, 2009 AT 9:42 PM
Tiny
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It is funny that you mention that the sensor could have been robbing me of gas mileage. Since I have replaced the sensor this past weekend, I am getting much better gas mileage. I would normally get three hundred miles to a tank of gas. I am now going on three hundred and fifty and still have a quarter tank left. I am guessing that the sensor had probably gone bad long before I realized it. I wonder if replacing the other three would make any more of difference?
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Wednesday, February 25th, 2009 AT 9:14 AM
Tiny
BLACKOP555
  • EXPERT
It is a gamble. It would not hurt to replace them with the age, just replace the bank 2 sensor one. Do not worry about the bank 1 and bank 2 sensor twos, the ones after the converters. All they are for is monitoring the catalytic converter to tell if that is still working or not it has nothing to do with gas mixture.
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Wednesday, February 25th, 2009 AT 6:38 PM
Tiny
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Just recently there appears to be a whining/whirling noise coming from underneath while in drive. It occurs when in drive and not moving and gets worse/louder when pressing the gas. I had the transmission rebuilt at 120,000. Any thoughts on what this could be?
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Wednesday, May 27th, 2009 AT 8:19 PM

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