oxygen sensor locations?

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.

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!

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.

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.

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!

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?

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.

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?

1997 Ford Explorer V8 all wheel drive automatic.

Is the 02 sensor bank 2 down stream located on the right or left side?

I have attached a diagram below of the Oxygen Sensor locations for you truck.

Let us know if you need anything else.

Okay, my SUV has been running to lean for the longest time. I have had it tested for codes and it keeps saying bank 1 sensor 2. Well I replaced that one and replaced bank 2 sensor 1 also because I was told it was going bad. My engine still runs too lean. While doing an oil change I noticed bank 1 sensor 1 o2 sensor was not plugged in. I figured this is where the problem is. Now I cannot find the wire to plug the sensor back in. I have looking under the motor where the sensor is and up top under the master cylinder and brake booster and I still cannot find the other end to plug the sensor back in. If anyone knows where the wire is please let me know. By the way, my engine is the OHV 4.0 if this helps.

When it comes to sensors,especially oxygen sensors they are telling you what is going on with the fuel/air ratio, by giving you a lean code does not mean sensor failure. Do not shoot the messenger in other words and do not let a parts store tell you what you need. The most common failure in these is either the intake seals or PCV hoses. Spray a little water over the intake and listen for a slurping sound.

Looking for upstream O2 sensors for the Explorer it is an 4.0L EFI OHV engine, thanks.

Should be before converters.

Do you have a diagram of where they are all at? Thanks.

No, I checked in our manual and they just said location. All you have to do is follow exhaust manifolds down to converter. There are two before and two after converters.

Okay, thanks I found them. Also, is it possible for the SUV to have its fuel trims at -100 running rich, but have a check engine light p0171 as it is lean?

Was running fine about a week ago, with gas slowly going away, but now it came with codes p0171, p0302, p1131 and my gas is going by incredibly fast.

171 is running lean and 302 is misfire on number two cylinder both of these can be caused by low fuel pressure. 1131 can be caused by the items in picture which includes fuel pressure which should be 30-45 psi. Auto parts rent gauge. If pressure is okay then I would suggest having a pro diagnose this as it is extremely hard to find cause of misfires.

I have a 1999 Ford Explorer 4x4, 115,000 4.0L V6.
The check engine light is on, the test was performed at our local auto store showing the oxygen sensor needs to be replaced. I am looking for any information on how to replace this ourselves. I have searched the many sites and seen that there are possibly two that needs to be replaced as well, as I was under the assumption that there was only one. But I have not found any information that states exactly where they are located and the easiest way to go about changing them. Or if it is better to take it to an auto shop and pay them to do it? Any help would greatly appreciated.

There is one right before the catalytic converter and one after the catalytic converter.

Where is the oxygen sensor located On a 1996 Ford Explorer two wheel drive?

It is on the exhaust pipe of engine.

Yes, all four of them.

I have a problem with my '99 Explorer. It will start up but then surges up and down at idle and eventually stalls. Also, when driving it you must give it very little gas or it will braek down or miss but let off the gas and it idles again fine? I was told this may be O2 sensors? I pulled 2 codes "PO135" and "PO161" are these sensors located just after the manifold or and these the rears? Hope someone replies. THANKS

Since no one else is answering, I'll give it a stab. The way I understand it, Bank 1 is the passenger side and Bank 2 is the driver's side on a forward facing engine. The codes you got are for Bank 1 Sensor 1(P0135) and Bank 2 Sensor 2(P0161). The codes are "heater short or open" and "heater circuit fault". So Bank 1 Sensor 1 is the passenger side sensor before the cat and the other sensor would be driver's side after the cat. You didn't say which engine you have, 5.0 or 4.0. Sensor 1 on both sides is the sensor that gives information to the computer to control air fuel mixture by controlling the fuel injectors pulse width. Sensor 2 is after cat and is a catalyst monitor.
I would check the wiring going to the sensors. I've seen sensor wiring heated up to where it was brittle and fall apart when you touch it. It seems funny that both sensors, on opposite sides and one forward the other after cat would go bad at the same time. The sensors could be bad, but again, I would check the wiring very closely. Do this when the engine is cold.

Electrical problem
1998 Ford Explorer 6 cyl Four Wheel Drive Automatic

How can I change the left oxygen sensor before the catalic??
where is it located?

It will be located on the side of the exhause system (before the exhause). Basically, it just unbolts and the new one screws in. NOTE: Make sure to get some anti seize and put it on the threads of the new sensor. If you don't, you will have a really hard time removeing it if you need to replace it again in the future.

Let me know if you have other questions.

Joe

I am trying to locate the locations of the O2 sensors in my 1994 ford explorer.

Can you advise?

The Heated Oxygen Sensor #1 is located on exhaust pipe of engine.


The Heated Oxygen Sensor #2 is located on exhaust pipe of engine.

where is the location of the vss and heated oxygen sensor? also how do you replace them

The 02 sensors are in the exhaust, not sure if I have a picture?

ok cool thanks yea i figured they would be would they be closer to the cats or the manifold

Not sure of the function of this part. The part is coming from cooling system and is intercepted with this particular part . It has 2 hoses coming in and 2 going in the fire wall from it. It appears to be a relief valve of some kind. It is leaking coolant from it. Do I replace it or is there some other problem? Is my thermostat sticking causing this problem.
Also, where is my O2 sensor located at? How do I relplace it and what is its function?

Well I think the coolant leak is the heater control valve. This valve is what controls how much hot coolant gets to the heater core thus controling the temp. See pic below if that is what you are talking about then simply buy a new one (cost about 20) with some antifreeze and change it top the coolant back up and your done. Now as for the O2 sensors you have 4 two in or near the exhaust manifolds and 2 underneith the truck after the cats. The O2 sensor read exhaust temp thus helping with how much fuel the engine gets.