Did mechanic break my O2 sensors?
#1
Driver School Candidate
Thread Starter
Join Date: Mar 2013
Location: NJ
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
I have a 1999 Lexus ES 300 with 60k miles on it. A few days ago, I took my car to a mechanic to fix a valve cover gasket leak. They did the job, but when I got the car back, the Check Engine and Trac Off light were both on. I immediately brought it back and they said some wiring on the front oxygen sensors were loose because they were bad to begin with. They also said it was no big deal and I could continue driving with it, but the lights might flicker on if the road was bumpy. I haven't noticed much of a difference in performance/mileage, but the lights have stayed on the whole time.
1. Did the mechanic break the O2 sensors with the valve cover gasket job? The CEL/ Trac off lights were not on when I brought the car in. If he did, should I ask him to replace my O2 sensors for free or pay for the part myself and ask him to cover the labor?
2. If I don't fix it and don't notice any obvious mileage changes or smells etc...what will be the long term damage? Is this something that can wait a few months?
Thanks all for your help!
1. Did the mechanic break the O2 sensors with the valve cover gasket job? The CEL/ Trac off lights were not on when I brought the car in. If he did, should I ask him to replace my O2 sensors for free or pay for the part myself and ask him to cover the labor?
2. If I don't fix it and don't notice any obvious mileage changes or smells etc...what will be the long term damage? Is this something that can wait a few months?
Thanks all for your help!
#2
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
The wiring harness has to be moved out of the way and wrestled
when doing the valve cover job. I doubt the oxygen sensor it self is broken. More than likely either the oxygen sensor isn't plugged in or they broke one of the wires in the harness. You should find the oxygen sensor and follow the wires into the harness and see if there are any obvious signs of a broken wire. if you can't find anything, Defiantly have them fix it and tell them you think they broke a wire. You can continue driving it like that but in most states it won't pass emmisions testing like that. Also if someone else has to fix it and they want to replace the whole harness it can get expensive so have them take a look while you have a chance.
![Smilie](https://www.clublexus.com/forums/images/smilies/smile.gif)
#4
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
Oh yeh so there are 2 oxygen or air fuel ration sensors under the hood. One in front of the radiator on the exhaust and the other one is behind the engine, passenger side on the exhaust.
#5
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
I don't see how changing valve cover gasket would affect O2 sensor. They might've forgot to plug in a harness.
I would check code to see which code(s) you get, maybe its not even O2 related.
I would check code to see which code(s) you get, maybe its not even O2 related.
#6
Driver School Candidate
Thread Starter
Join Date: Mar 2013
Location: NJ
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
mitmaks after I brought it back in with the warning lights on he confirmed it was the O2 sensors. The lights were not on before the job, and now they are on. What else could explain this if he didn't do something to the O2 sensors?
Trending Topics
#8
Driver School Candidate
Thread Starter
Join Date: Mar 2013
Location: NJ
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
No he did not tell me the actual codes, just that some of the wiring was bad to begin with. He reset the lights so they were off at the time but they came back on about a mile later. So in your opinion it is possible that he broke the wiring doing the gasket job? I told him to fix it for me but he claims they were faulty to begin with. He also said it was okay to drive around with but I might notice a change in mileage. What should I do? Thanks again.
#9
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
He told you it will be fine to drive it like that? Sounds like some shoddy mechanic to me, where did you find this guy at? Definitely have it fixed. You don't want to loose mpg due to o2 sensor not being plugged in/bad wiring. And of course you won't pass emissions with CEL on.
#10
Lexus Champion
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
You could end-up ruining the Catalytic converter, so it needs to be dealt with.
It could have also been a freak coincidence who knows, however at your current 60k miles, they should still be good.
Phil
It could have also been a freak coincidence who knows, however at your current 60k miles, they should still be good.
Phil
Last edited by PFB; 03-07-13 at 12:57 PM.
#11
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
![Egads!](https://www.clublexus.com/forums/images/smilies/pat.gif)
Pretty good chance they broke the wiring during this step.
#12
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
Davensd
Thread
Thread Starter
Forum
Replies
Last Post