I am really furious now after checking almost 10 places to replace my O2 sensor and all they them say it's $150 for the sensor (I checked myself at autozone: only $60!) and 1-2 hours of work total up to around $250!

I'm gonna do it myself now. If anyone has done this before and can help me through it, I'd really appreciate it. I'm just nervous because those auto repair places said it takes specific equipment, testers, etc and 1-2 hours of work to replace this thing. I've heard of people replacing this within 20 minutes on the org with no special equipment. What's up?

Anyway, heading back to autozone right now to pick up the sensor and the installation tools.

 

I did mine in five minutes. Just spray the sensor to be replaced with WD40, let it soak then remove it with a wrench or ratchet. Put some antiseize on the new sensor and screw it in. Easy as pie.

~THT

 

Where is it located? I heard near the manifold?

Also is the front sensor before or after the catylitic converter? I bought both kinds (before and after) so I won't have to drive back there today.

 

You need 2 front and 1 back(pointless since it doesn't do anything). The front 2 have different length cables so make sure you have the right ones. Raise the car, get under there and look at your y-pipe. The 2 different pipes coming down from the engine have the o2 sensors in them.

 

The rear one is in the latter half of the cat.

~THT

 

I have both front sensors. The one on the front manifold looks easy but the rear one, I dont know where the conector is. The wire just goes up somewhere. Anyone know how to replace that one?

 

NooB question: What is the difference between the 2 front O2 sensors and the rear sensor? Why do you say the rear sensor doesn't do anything?

 

Front two are the same sensor, they jus have different lenth of wire. They have take part in the air/fuel ratios and the rear one has nothing to do with performance, just tell you if the cat is bad...i might be wrong about that.

 

The back one does do something. I doesn't control performance directly but it does control A/F ratio and therefore fuel soaking your motor, killing fuel economy and causing rich/weak situation when bad. My rear one is bad right now and I'm getting less than 300 to a tank on granny driving. Its reading 0 volts. This makes the ECU think that its not getting enough fuel and therefore attempts to adjust. Its in the mail and should be on by Saturday. All o2's on the max utilize the same sensing unit, its just that the harness is a different length, as JeEvE and Big D mentioned. If you don't think it does anything check my homepage. On page eight there is a graph illustrating exactly what I'm speaking of. The rear one on 4th gens is in the cat while 4.5 gens have it in the piping at the beginning of the B-pipe. It is true however, that when working properly the rear heated o2 does very little for performance or engine adjustments in general.

Replacing them would not be hard if you had a Y-pipe. If you have a stock Y you will probably have to drop that out. Once you have clear access all you need is a wrench. To unplug the bank 2 sensor simply follow the harness and unplug it. The plug should be right in front of the front valve cover. There are several zip ties along the way though and the harness ends up going through the engine support, at least thats the way it was on my car. No special tools or testers required except a reset of the ECU to clear codes.

 

Thanks a ton to all.

I understand why you say spray it with WD now. that thing is tough to remove. I'll check on it early tomorrow and put the new one on.

 

Is it a good idea to replace both right and left sensors when only one (left) is bad?

 

When the ecu code says the "left" is bad, is it my left if I'm sitting in the driver's seat or if I'm standing in front head on to the car?

 

jack up the car a bit. make sure she is cold. burnt hands arnt nice. put her on jack stands. both front o2 sensors are on your ypipe..use a rachet withan o2 sensor socket to get that baby out.. wd40 helps alot. let it soak for 5 mins.. u can also use a 22mm wrench.i think its 22. now scrwe in the new sensor. follow the wireing path. plug it in.. good to go.

Front Left/Right O2 sensor = Left/Right in this case refers to the left/right bank of the engine. The "Left" sensor is the one furthest to the front of the vehicle. closer to the firewall, not the radiator.

 

I always remember left and right by thinking about the engine layout on a RWD car. Lets take a Z for example. The tranny faces toward the back of the car and is therefore the back of the engine. The opposite is the front of course. Think about it and the left is front right is rear. I know it may be common sense to some of us. Just thought I'd help out the newbies.