Noah911

You definitely do not need to change all of them! The mechanic really may just be wanting to make some extra cash off you? I mean, the best practice would be saying to have all of the oxygen sensors updated new all at the same time. But, if the others still work just fine there is not a need, and that is a lot of money in sensors!

I see what the difference is of the codes. One of them is for the pre-cat sensors (P0135), while the other is for the post-cat oxygen sensors (P1041).

Oxygen sensors never even used to have a heater element in the past. They come with a heater element nowadays though, because they will work much better when heated really hot.

Do you know this mechanic? Has he done any work for you on anything in the past? I would not trust him. It sounds like he put bait out for you, to see if you would bite? It sounds like shady practice. If you ended up agreeing to let him do the work replacing all of them like that. Who knows what the actual bill would have ended up being when you went back to pick up the Jeep from this guy. There may be an additional one to two hundred dollars, for this and that, tacked onto the already exuberant price he quoted you for unnecessary work that is not needing to be done. You would have to pay it too.. if you wanted your Jeep back, since at this point he would have a mechanics lien on it.

BlueRidgeMark

I'm with Noah on this. If you had to do some crazy, labor-intensive operation like pulling the engine, or even the exhaust manifold, to change an O2 sensor, then maybe it would make sense to change them all. Otherwise, it's just ripping you off.

Sensors do fail. Wiring also goes bad. Fuses blow (for the heater). So, you need to do some troubleshooting before you replace one.

Noah911

If the sensors come out easy? It is only a five minute job too...

MaskedMallard

If you are able to turn a wrench, the Oxygen Sensors are just as easy as changing a flat tire. Also, I would recommend using NTK, as that is believed to be the supplier of the original Mopar part.

Here is my story about my Oxygen Sensor expense (if it's not broke, don't fix it). I decided to change all 4 Oxygen Sensors (from Amazon) on my XJ, with 100,000+ miles. No check engine light was on at this time. So, after installing all 4 Oxygen Sensors, I got a code for low cataltic converter efficiency. I found out that with 4 brand new sensors, my cataltic converters were failing. My original $300 job of replacing all 4 O2 sensors now became a $1000+ do it yourself job. I replaced both cataltic converters, crankshaft position sensor, & put a Doug Thorley exhaust header on the Jeep.

With what I discovered, if I were to do it again, I would have only replaced both the upstream oxygen sensors & not touched the rears. At least not until the rear oxygen sensors trip a code. The lazy rear / downstream oxygen sensors were saving me money until I replaced them.

The front / upstream oxygen sensors are good for engine performance & fuel economy. The rear / downstream oxygen sensors are good to let you know if you have efficient cataltic converters.

If you decide to do the job yourself, buy NTK sensors. Take the sensor to a hardware store to buy the correct size wrench. Crawl under the Jeep & disconnect the front O2 sensor you want to replace. Slide the connection end through the box end of the wrench (or cut the wire on the sensor), and wrench / twist the old O2 Sensor out. You might be able to use the open end of the wrench to loosen / remove the old O2 sensor. Just beaware you run a greater chance of rounding the nut on the old O2 sensor. Install new sensor with open end of the wrench & snug it down, reconnect plug to body harness of vehicle.

jeep58

Well thanks for the advice I will do the one sensor myself when weather permitted, The price on that one job to replace all sensors blew me away! I did not know that the sensor used to come w/o heater element always learning. Thank you!

Noah911

Was this an independent mechanic, dealer, or a chain shop? I am curious what is the name of his business? It's not important though..

jeep58

The mechanic is someone i use i know the owners son and they do good by me most of the time. This guy works for the owner who gave me the price, every now and then i get a wild price from him but i do not bite it is not a problem for me!

Noah911

Some mechanics are funny people. I swear in my life I have only ever met one honest guy in the business. Although, it is not like I really go around talking to, and meeting a ton of different mechanics either. It is not like I have a very large sample of people to make a fair assessment.

I decided to stop practicing in the field of nursing a few years back.. Long story short; I quit my job and went about looking for a new second career. During the interim between then and now, I tried working a few different jobs before I ended up getting into something where I was wanting to be..

I moved to a new location. I didn't really know anyone living there. I met this guy. He seemed alright to me. He said he could use me for working around his shop/garage doing oil changes and stuff. I worked one day in his shop and I never went back. One of the first things he says to me while standing there with his other guys, was that he runs an honest business etc... You should have seen the crap I saw them pulling, and I only observed them for one day. They were in the business of ripping people off is what they were all about..

I was working with them on this one vehicle. They pulled a single spark plug and looked at it, and called this a tune-up. They used JB weld to fix an oil leak this car had (the primary reason for why this car was in the shop). They lied to the man, and called it a $900 job saying they replaced his oil pan when they did not.. telling the man they dropped the cars axle and all of this other stuff to get it done when they did not. I saw maybe twenty minutes of actual work being done on this car. Immediately right before calling the man to tell him his car was finished and ready to be picked up, they all conveyed together to talk and get their stories straight. They were all just basically acting when the owner got there and were purposely putting on a show... What really blew my mind though. I ended up finding out while they were all talking together was this was one of their own family members vehicles whom they did this to. It was soo messed up!

I just walked away and didn't even bother asking for my pay.

jeep58

What I say to people like that bad karma, One day they will get it and they will saying "why me". I do not wish bad things on people but I do believe what comes around goes around! You sound like a good man Noah, always glad to hear your replies.

dave1123

Here's a clue. The 02 sensor supply wiring goes across the engine behind the head in the bundle that contains the wires for the coil rail as well. Since this problem appeared just after you changed the spark plugs, there could be a broken wire in that harness that you flexed when you disconnected the coil rail. As with the door wiring bundles, a broken wire can reconnect itself and work sometimes, sometimes not. The 02 heaters only prewarm the sensors to make them begin to function sooner on startup so as far as mixture control, I wouldn't be too concerned about the heater not working, unless you have an inspection coming up soon. As far as replacement is concerned, I'd only replace that one, but only after I checked for a wiring fault.

Case in point; my 2000 WJ had a sensor shorted to voltage, meaning the heater circuit was making contact with the sensor signal wire. I changed that sensor and still got the code. Checking the wiring, there was a frayed section behind the head. Fixed the wiring, fixed the code. This engine has 253K miles on it with the original sensors, except that one.

jeep58

I reset the stored code and the light has not returned, yes maybe frayed wire but for now it will wait when I get a chance to check everything out.