Replace front o2 sensor procedure - Very Easy or Easy? (1 Viewer)

Joined
Aug 26, 2005
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8
check engine light indicates I need to replace the front , passenger side o2 sensor. I have the part ordered, and was just wondering:

1) how hard is this to replace? I'm not exactly savy at this type of stuff, but I can do some basic stuff
2) any procedures/pics to where I can find the o2 sensor? I'm not even sure I know where to look

Thanks!!!
 
Joined
Oct 28, 2006
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361
Location
Kirkland, WA
I did this just (last?) weekend.
Error code P0155.

Remove the plastic "splash shield that cover the transmission (6 bolts, 12 mm). Follow the exhaust pipe up and you will see the O2 sensor clearly. I did post a picture, will try to find the post and link to it here.

You can easily get to it with properly sized crescent wrench, or a fixed wrench. I'll be running down to basement and provide the measurement in a little while.

If you cannot get it lose, start car and run fora short whle in order to heat up the exhaust. Might be easier getting to it then (note, I had not problems with either of the front ones).

When re-installing, add anti-seize, but MAKE SURE you keep the acual sensor clean!
 
Joined
Oct 28, 2006
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Kirkland, WA
OK, not great photo, but look under:
https://forum.ih8mud.com/showthread.php?t=148769&highlight=sensor
post 10. You'll see the O2 sensor.

Or, did find a slightly better picture...
You can see the anti-sway bar in the bottom of the picture. Taken from below, up "along" the firewall. top of photo is towards the rear of the vehicle.

BTW, I did buy my OEM Denso O2 sensor from www.sparkplugs.com. Was just about $100 including shipping. Short pigtail that plugged in like "new". Hence, no splicing of wires, even though that's an easy task as well.

And, the job is VERY easy, as long as your sensor is not stuck.
20070411_0165 (Medium).JPG
 
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Joined
Aug 26, 2005
Messages
8
Wow! great instructions. I found that sucker tonight (in the dark!) and will attempt a replacement in the morning. however - it looks very tight in there and maybe it's the angle I'm coming at it from, but i'm not sure how easy it will be to manuever a wrench in the tight space

any ideas?
 
Joined
Oct 28, 2006
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361
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Kirkland, WA
I used a crescent wrench of "medium" size. I had it sort of "upwards" when untightening it.

I did measure the old sensor and it looks like it is a 22 mm, but caliper is not of that high quality so it might be a 21 mm.

I did the job just crawling under the truck. Relatively easy. When done I realized I have a pair of ramps I could have driven up on.

Oh, BTW, getting the connector to split is a bit of a pain since you really need two hands for its and there's no way you can get two hands there at the same time. It did "poke" at the locking clip of of the connector so the two halfs easier would split apart.
 
Joined
Jun 10, 2007
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4
Location
NW Indiana
A newbie here...and 1st post...

Had the same Error code #155. Wellcraft19 - Your instructions and photos were excellent!!! I went thought the wheelwell yesterday and finished the job in no time. Only difference was that I had to removed the front right tire to get more space.
 
Joined
Oct 28, 2006
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Kirkland, WA
Hey, glad it worked and you got some help. Just trying to "re-pay" some of the many tips I've gotten here.

BTW, I saw HORRIBLE gas mileage on the first fill-up AFTER the new sensor. Only got around 190 miles on that tank!

But, on 2nd fill-up, back to normal. Getting around 330 miles to a tank.
 
Joined
Aug 29, 2005
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cedaredge, colorado
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weknowsnow.com
it's pretty easy.. i was just under there with my friend to tap into the sensor wire for an air/fuel guage.. pretty easy access once you remove the skid plate. 12mm

blue wire is the sensor wire.

.1v - .7v

black sames to be power

white ??

4 wires
 
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Joined
Jun 10, 2007
Messages
4
Location
NW Indiana
The front passinger side is Bank 2 Sensor 1.

As an FYI...Bank 1 is on the driver side...and is so named (as I was told) because this is the same side as cylinder #1. Bank 2 (and cylinder #2) is on the opposite side of the engine (passinger side).


Since I changed the sensor, (just as Wellcraft19 predicted) I'm seeing HUGE fuel efficencies...which translates into money saved given today's gas prices....
 
Joined
Jan 18, 2005
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7
I did measure the old sensor and it looks like it is a 22 mm, but caliper is not of that high quality so it might be a 21 mm.

I think it's actually 7/8" (at least, that's what the special O2 sensor socket I purchased was), which translates to just a hair more than 22mm. Both sizes should work if you are just using a wrench. The socket was a little hard to use in the cramped space when tightening things.

I changed out both front O2 sensors about a month ago and have noticed a pretty nice improvement in gas mileage.

Colin
 
Joined
Jan 30, 2003
Messages
3,309
Had the P0155 on wifes truck, went in through the wheel well and ran into more hard lines than mark. Used a 7/8" O2 crows foot that was like a flare nut wrench. Like others said, the hard part was getting plug undone...finally figured out to slide a small screwdriver under the tap and slightly lift, which allowed plug to slide out.
 
Joined
Jun 13, 2007
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AZ style
Another helpful little tidbit, remove the tire on the side you're working on (use jackstand). It makes all the difference in workspace for us bigger guys. I also recommend changing both sides while you're at it just to keep it real (if changing one upstream ,do both upstream so they're even)
 
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Joined
Nov 11, 2005
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393
Location
Delaware
I have really found that it is exhaust rust dependant.
The more rust the harder it is. A quick blast of PB the night before makes all the difference in the world.
 
Joined
Oct 31, 2006
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Houston, TX
Does any body knows the cost of this O2 sensor. If this improves gas milage as some have said, I sure want to do this. I am getting only about 250 miles for a full tank after I put 285's. I was geting about 300 before
 
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Mar 17, 2007
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Albuquerque, NM
Does any body knows the cost of this O2 sensor. If this improves gas milage as some have said, I sure want to do this. I am getting only about 250 miles for a full tank after I put 285's. I was geting about 300 before

Remember, you went to a bigger tire, so are you adding the 6% difference in tire size?
 
Joined
Nov 13, 2007
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693
Location
nashville tn
check engin light

just chipping in
replace my front sensor and had light reset
come on after15 miles
why ?
thanks
 

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