Oxygen sensors?

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.

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.

Those are lean codes. I'd check for a vacuum leaks. Also, incorrect airflow can cause problems.

Thank you for all your help. It is very much appreciated.

No problem, have a good day.

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?

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!

Electrical problem
2002 Ford F150 6 cyl Two Wheel Drive Automatic

EASIEST WAY TO REMOVE THEM

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.


.

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

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

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 ?

Thanks for your help. Just curious, can there be 4 O2 sensors?

Electrical problem
2002 Ford F150 6 cyl Two Wheel Drive Manual 53000. miles
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how to change the oxygen sensor and where its located or how to clean it

Pretty big leap going from the CEL on to changing the O2 sensor.

What codes are in it?

just trying to figure this out without spending money i don't have

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?

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

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.

mark (mhpautos)

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

O/2 sensors will slowly lose sensitivity from contamination. If yours are original, they are overdue for routine change. They won't set a code until they get extremely bad and don't respond when the are expected to. If your complaint is just about a couple MPG, changing the sensors would be a good idea. You've got 154K on that truck. I remember when that was the entire life of the truck. Now it's just when you start doing some maintenance.

Looking to find the locatoin of the o2 cencor.Ive changed the fuel filter an the plugs an wires an stil get the service engine soon light.

What is code? If you have not read code go to Auto Zone or similar then post.

The code says its running lean on left an right banks

Do you remember code in P0xxx format?
Possible faults:
EGR operation ie. leaking
Vacuum leak
Exhaust leak before cat.
Low fuel pump pressure

"check engine soon" warning appeared so I took the truck to my repair shop and they said one of the sensors needed to be replaced but all three should be replaced at the same time. All three were replaced and before I had gotten home, the light came on again. The shop told me there was a 50 key start reset?
If it was reading a bad sensor, wouldn't a new sensor prevent the warning from appearing again. Are there actually three and why would it require 50 starts to reset?
Thanks.
Mike Johnson

DTC P0135, P0141, P0155 Or P0161: HO2S Heater Circuit DTCs received separately indicate a short to ground or open circuit in HO2S heater circuit. DTCs received in pairs, such as P0135 and P0155 or P0141 and P0161, indicate HO2S heater circuit is shorted to a power source of more than 2 volts. HO2S DTC identification is as follows: DTC P0141 Is For HO2S-12 DTC P0155 Is For HO2S-21 DTC P0161 Is For HO2S-22 Refer to illustrations for HO2S identification. Possible causes are: Signal Shorted In Wiring Harness Cut Or Pulled Wires Open In GND Or VPWR Circuit Corroded Terminals Faulty HO2S Heater Inspect HO2S connectors for loose, damaged or corroded terminals ,Water In Connectors

Engine Performance problem
2000 Ford F150 V8 Four Wheel Drive Automatic

Can you please tell me where the oxygen sensor is located on this vehicle, Thanks

there a several oxygen sensors on your vehicle.
sensor one bank 1 is the first sensor before the convertor on the side of the engine with the #1 cylinder. that is the passanger side.

sensor one bank 2 is on driver side.

sensor 2 is after the convertor

when the engine is cold will start but when warm the starter will not do any thing, the computer find the engine runing at 55 mph and 208 degres when ideling in park position, and finds oxigen sensor of bank 1 # 02
to be defective.
If I throw wather with a howse to the oxigen sensors on the catalitic converter and coole it off , will start imediately.
Does the oxigen sensors by been hot or damage prevent 12V from going to the starter?
This engine has 310,000 miles and never change any sensor.

No, it doesn't stop power to the starter. Are you getting the starter wet?

yes, I wet every thing from the top of engine and nothing hapen but wen I wet from under the frame all exost pipes and catalitic converter , probably starter too, estart imediately , starter seems to work perfect wen works

What I was thinking was the starter was getting hot from the engine and not working. What you have described, with the O2 sensor, doesn't make sense. However, if cooling it off does the trick and you have a code for it being bad, it's worth replacing.

Engine Performance problem
2000 Ford F150 V8 Four Wheel Drive Automatic 71K miles
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Where is the oxygen sensor on ford f-150 engine?

There are four total if I'm not mistaking. There is one on each side of the exaust manifolds easy to see under the hood right before the firewall. And two more under the truck on the exaust before the converter.

Too lean bank 2 sensor 1... That code went away. congress back off and on. But I get another code I forget the code number but it says bank 2 sensor 1. 02 sensor responding to slow. change sensor?

Hi Jack,

See the attached for the detail about o2 sensors. Sensor 1 bank 2 is the upstream sensor on the passenger side.

Usually the slow to respond codes are the sensors. However, there are some tests that can be run in order to confirm this. If it were me I would just go ahead and replace it because they are cheap enough to "play the odds" that this will resolve the issue.

Let me know what happens after you replace the upstream sensor on the passenger side and we can go from there. Thanks