Oxygen sensors?

Tiny
ACES LOADED
  • MEMBER
  • 2002 FORD F-150
  • 175,000 MILES
I have an F150 FX4 Supercrew truck. I was told I needed to replace my O2 sensors because my check engine light came on and the truck is shaking. I have located one that I can see thru the drivers side tire well, but I don't see anymore. Is there only one O2 sensor and are there any easy steps to replace. I am a novice when it comes to car mechanics. Thank you.
Wednesday, November 30th, 2011 AT 4:26 PM

37 Replies

Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
Two in each exhaust bank, before the catalytic converter and after. That number should tell you which 02 sensor/which circuit. Here is a guide to help walk you through the repair plus I have included the location of the sensors in the diagrams below.

https://www.2carpros.com/articles/how-to-replace-an-oxygen-sensor

Check out the diagrams (Below). Please let us know what happens.
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Wednesday, November 30th, 2011 AT 6:08 PM
Tiny
ACES LOADED
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PO171 and PO174 are the 2 codes the auto store gave me. They said to try Air Flow Sensor cleaner first because that is way cheaper. I haven't tried anything yet. And the truck is not dual exaust.
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Wednesday, November 30th, 2011 AT 7:40 PM
Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
Those are lean codes. I'd check for a vacuum leaks. Also, incorrect airflow can cause problems.
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Wednesday, November 30th, 2011 AT 8:28 PM
Tiny
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Thank you for all your help. It is very much appreciated.
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Wednesday, November 30th, 2011 AT 8:57 PM
Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
No problem, have a good day.
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Wednesday, November 30th, 2011 AT 9:08 PM
Tiny
ROY J
  • MEMBER
  • 1 POST
  • 2002 FORD F-150
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 100,000 MILES
I have noticed loss of power and service engine soon signal on. I have replaced plugs and I think wires are good. What other areas to check? Could this be caused by a bad sensor? If so where is it located and what is involved in replacement?
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Thursday, September 10th, 2020 AT 6:13 PM (Merged)
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Remove the guesswork. First thing you need to do is have the codes read, Autozone does it free, Post the results with the code number(s). Even if the service engine light is not on, there should be freeze frame data stored.
If it won't make it to Autozone, buy a cheap scanner, they can be had for 30-40 dollars, a good investment, since they cover all cars sold in the USA from 96 on.
If the light is blinking, it means engine misfires possible damage to the Catalytic converter. Service it right away!
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Thursday, September 10th, 2020 AT 6:13 PM (Merged)
Tiny
EZTOBEFOUND
  • MEMBER
  • 6 POSTS
  • 2002 FORD F-150
Electrical problem
2002 Ford F150 6 cyl Two Wheel Drive Automatic

EASIEST WAY TO REMOVE THEM
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Thursday, September 10th, 2020 AT 6:13 PM (Merged)
Tiny
OBXAUTOMEDIC
  • MECHANIC
  • 3,711 POSTS
Hello,

They make a special socket for them, however, they are sometimes placed in areas were you cannot get the socket on them so a wrench would work better.

Also, if you warm the exhaust up some will also help with them breaking loose easier.

.
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Thursday, September 10th, 2020 AT 6:13 PM (Merged)
Tiny
EZTOBEFOUND
  • MEMBER
  • 6 POSTS
Your information on this was a big help job completed hardest part was getting my hand behind the engine to connect the the plug back together on one of the sensors. Thanks Norm
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Thursday, September 10th, 2020 AT 6:13 PM (Merged)
Tiny
FRANK IACONO
  • MEMBER
  • 2 POSTS
  • 2002 FORD F-150
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 64,000 MILES
Diagnostic from Auto zone says bank A running lean. Mechanic says to replace all 4 O2 sensors. Are there really 4 sensors? Thought vehicles only had 1 sensor for O2
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Thursday, September 10th, 2020 AT 6:13 PM (Merged)
Tiny
DAVE H
  • MECHANIC
  • 13,384 POSTS
Depending on which engine you have there are probably 2 H02s sensors. For a lean condition I would advise removing and cleaning MAF sensor before replacing any other part?
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Thursday, September 10th, 2020 AT 6:13 PM (Merged)
Tiny
FRANK IACONO
  • MEMBER
  • 2 POSTS
Thanks for your help. Just curious, can there be 4 O2 sensors?
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Thursday, September 10th, 2020 AT 6:13 PM (Merged)
Tiny
CAROLYN0322
  • MEMBER
  • 3 POSTS
  • 2002 FORD F-150
Electrical problem
2002 Ford F150 6 cyl Two Wheel Drive Manual 53000. Miles

how to change the oxygen sensor and where its located or how to clean it
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Thursday, September 10th, 2020 AT 6:13 PM (Merged)
Tiny
SERVICE WRITER
  • MECHANIC
  • 9,123 POSTS
Pretty big leap going from the CEL on to changing the O2 sensor.

What codes are in it?
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Thursday, September 10th, 2020 AT 6:13 PM (Merged)
Tiny
CAROLYN0322
  • MEMBER
  • 3 POSTS
Just trying to figure this out without spending money I don't have
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Thursday, September 10th, 2020 AT 6:13 PM (Merged)
Tiny
SERVICE WRITER
  • MECHANIC
  • 9,123 POSTS
Exactly my point.

There are a multitude of possiblilities for a check engine light, that is why you start by getting the codes out of the computer to give insight to the problem(s). How pricy will it be to just blindly replace parts?
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Thursday, September 10th, 2020 AT 6:13 PM (Merged)
Tiny
SMITH65
  • MEMBER
  • 1 POST
  • 2002 FORD F-150
Engine Performance problem
2002 Ford F150 6 cyl Four Wheel Drive Manual

im getting ready to purchase a 2002 f150, the seller says all four converters are gutted out and both 02 sensors our bad, what kind of price range am I looking at to get those repaired
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Thursday, September 10th, 2020 AT 6:14 PM (Merged)
Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
Hi there,

Cats are very expensive, there should only be two and at these prices you will not want 4, price is from Mitchell 1 data base, so i would first shop around as i am sure that you will get some cheaper that this, the )2 sensors are about $70 each, i have added the clip from Mitchell for the cat prices.


https://www.2carpros.com/forum/automotive_pictures/61395_price_1.jpg



mark (mhpautos)
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Thursday, September 10th, 2020 AT 6:14 PM (Merged)
Tiny
DEANRD
  • MEMBER
  • 1 POST
  • 2001 FORD F-150
  • V8
  • 4WD
  • AUTOMATIC
  • 154,000 MILES
I was told that my slight power loss and 2 mpg loss was due to O2 sensors being bad. I don't get a check engine light, but my truck now loses enough power going uphill in oevrdrive to cause it to downshift. It only started this in the last 6 months. Could the O2 sensors be bad and not set off a code? Would an ODBII test show anything? Should I just replace them?

Thanx - Dean
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Thursday, September 10th, 2020 AT 6:14 PM (Merged)

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