Help with front bank upstream O2 sensor

I replaced 3 of the 4 O2 sensors and tried working on the front bank, upstream sensor today. It is so tight in there, that I could barely get the O2 socket up in there with a wrench on it. I had to resort to an adjustable socket wrench with the head turned to a pretty sharp angle which was putting alot of incorrect stress on the sensor when I turned it. It didn't budge, and I was worried that putting anymore torquehttp://images.intellitxt.com/ast/adTypes/icon1.png (http://www.fordforums.com/#) on it would bust it off. I tried working from underneath the vehiclehttp://images.intellitxt.com/ast/adTypes/icon1.png (http://www.fordforums.com/#) and also down through the top, but nothing worked.
Any suggestions on getting this thing out?

I had heard about that one being so hard, so when I had to replace the radiator I put in a new sensor at the same time.
On another note, regularly check your coolant reservior to see if tranny fluid is floating on top. The factory radiators like to crack internally swapping fluids. It doesn't take long for antifreeze to seize up a transmission as I found out. My wife was the daily driver at the time and she thinks she just has to put gas in and everything else takes care of itself. So maybe you'll have to get two with one stone and with an easier access to that sensor. Though it sucks to pay for the radiator, it sucks worse to also pay for a transmission.

I was thinking that the only easy way to get to it was going to be to remove the grill and radiator. I think I'll hold off on that sensor until I have a problem with it. Meanwhile, the check engine light came on again yesterday and its showing a problem with the rear bank, upstream sensor. That one is only about two weeks old, so I don't know what the problem is with it now.

Thanks for the info

I was thinking that the only easy way to get to it was going to be to remove the grill and radiator. I think I'll hold off on that sensor until I have a problem with it. Meanwhile, the check engine light came on again yesterday and its showing a problem with the rear bank, upstream sensor. That one is only about two weeks old, so I don't know what the problem is with it now.

Thanks for the info

What is the code number? Probably a broken wire instead of a bad sensor.

I'm pretty sure it was P0155, which was the rear bank, upstream sensor. Today, I unplugged it, and disconnected the ground on the battery. Once I hooked it all back up, everything was reset, so I went through the steps to reset the PCM. Twelve miles into it, the check engine light came back on. I noticed when I put the new sensor in that the connection doesn't "click" as it locks into the female connection. Even when I go to unplug it, I don't have to move that locking tab for them to come apart, so for some reason its not locking together correctly.
I'll check out the wiring tomorrow, thanks.

I'm pretty sure it was P0155, which was the rear bank, upstream sensor. Today, I unplugged it, and disconnected the ground on the battery. Once I hooked it all back up, everything was reset, so I went through the steps to reset the PCM. Twelve miles into it, the check engine light came back on. I noticed when I put the new sensor in that the connection doesn't "click" as it locks into the female connection. Even when I go to unplug it, I don't have to move that locking tab for them to come apart, so for some reason its not locking together correctly.
I'll check out the wiring tomorrow, thanks.


P0155FordHO2S-21 (Bank 2 Sensor 1) Heater Circuit Malfunction

I just took a look at it and the tab must have broken off of the female connection from the computer. There is a place on the male end of the sensor wire where the tab should lock in, but its missing on the other connector. I was able to get a pair of pliers down in there and get it tightly connected, but I'll have to drive it a little to see if that helped.

Isn't the "grille side" of the engine bank 2?
Squeezing the piss out of it with pliers will probably damage the connector shells and distort the pins, affecting their contact. Just squeeze it together firmly with your hands and loop a ty-wrap through the wires from each plug end,male and female then cinch it up tight. If you find the plug is damaged and the contact of the pins questionable you can just verify the wiring connnections and crimp them together with heat shrink butt connectors.
If the P0155 returns you'll have to inspect the heater circuit not just the sensor. You should probably clear the codes with a scanner/ code reader so you can verify they are cleared and there is nothing else pending. You'll also know when a drive cycle is completed.

[QUOTE=65comet;7013537]I had heard about that one being so hard, so when I had to replace the radiator I put in a new sensor at the same time.
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Just wait till ya gotta change the alternator!

Bank 2 is on the driver side or on a front wheel drive ford the bank closest to the radiator. I believe this is the sensor you have not changed correct?? Yo may want to recheck the codes stored.

Bank 2 is on the driver side or on a front wheel drive ford the bank closest to the radiator. I believe this is the sensor you have not changed correct?? Yo may want to recheck the codes stored.

That's exactly what I was thinking.

If Bank 2 is the side next to the radiator, then that is the sensor I am having trouble with. The one that is in the worst possible spot.

[QUOTE=65comet;7013537]I had heard about that one being so hard, so when I had to replace the radiator I put in a new sensor at the same time.

Just wait till ya gotta change the alternator!

I already changed the alternator. Gotta thread somewhere about it. Because of a frontend accident, the normal area to squeeze it out was compressed a little small, had to actually unbolt and move the engine forward.

Originally posted by 65 comet: I already changed the alternator. Gotta thread somewhere about it. Because of a frontend accident, the normal area to squeeze it out was compressed a little small, had to actually unbolt and move the engine forward.[/QUOTE]
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Is that what you figured out for yourself? Front end accident or not you'll be spinning that alternator over and over like a "Rubic's Cube", trying to get it out. Until you remove the CV axle! :runaround:

Ok, so I had it reread and it is the front upstream sensor. I checked the wiring and it doesn't look to be damaged from when I worked on it, but I can't really see the top of the sensor where the wiring connects. If there is damage to it, thats probably where it would be since I was using the socket right there.

I'm not able to get to this in the next week, so besides possibly having lower gas mileage, what will driving this cause if I wait about a week?
I know that these things are heated for some reason, but what exactly is a "Heater Circuit Malfunction"?

Ok, so I had it reread and it is the front upstream sensor. I checked the wiring and it doesn't look to be damaged from when I worked on it, but I can't really see the top of the sensor where the wiring connects. If there is damage to it, thats probably where it would be since I was using the socket right there.

I'm not able to get to this in the next week, so besides possibly having lower gas mileage, what will driving this cause if I wait about a week?
I know that these things are heated for some reason, but what exactly is a "Heater Circuit Malfunction"?

Not much more than that. The heater allows the sensor to get "on line" with the CCM faster in order to obtain "closed loop" operation sooner.
A "malfunction" is usually an open or shorted circuit in the wiring or sensor.

Well, here is the SOB that I couldn't get out..
http://i972.photobucket.com/albums/ae210/dborns/IMG-20121201-00004.jpg
http://i972.photobucket.com/albums/ae210/dborns/IMG-20121201-00006.jpg
My last attempt at doing this myself had me going to three different hardware stores looking for a stubby socket wrench. I couldn't find a shorter one in 3/8", so I bought a 6" crescent wrench that would fit a 7/8" nut. I tried it, but still didn't have enough room to turn it. There is a vertical support bar that runs up the middle of the car that gets in the way. Its only held in by a half dozen screws, and if removed would probably allow for a wrench to be turned, but the hood latch assembly is connected to it. You would have to remove the assembly to get that support out.
So while I'm feeling around to get the crescent wrench on the sensor, I noticed it felt loose. At first I thought it was just the top part of the sensor, but then noticed it was turning out! I must have actually got it loosened the last time I worked on it and didn't notice, or maybe with driving it as I have, the hot/ cold loosened it. With it being loose, thats probably why I got the check engine light because the wiring and sensor looked intact.
It was a little difficult getting the new one lined up but I found that if you get it started in the hole, and take a flashlight looking down from the top of the motor, you can just barely see it. I was then able to tell if I was inline with the bung and make adjustments to line it up. I couldn't get my arm down to it from the top, so get it started from the bottom then see if its lined up from the top and make adjustments from the bottom.

Did you fix the problem?

Did you fix the problem?
I've put about 50 miles on it since I replaced that last sensor and have had no issues. No check engine light yet!