I recently swapped my Y-pipe and everything's been fine but now I see a SES light. I'm pretty sure it's a bad oxygen sensor but want to know what everyone's experience has been. Also tonight I'm going to disconnect the battery to try and reset the ECU.

Get codes from the ECU.....Autozone will do it for you. By resetting it, you'll never know why it was lit in the first palce.

well said^^^^^^^^^^^^^^

if you have autozone erase the code will it come back up if it is a continuing problem. or will the ses light always stay off even though there is still a problem.

O2 sensor Mine went after I got mine. Haven't had one since.

I got the SES after installing the Y-pipe as well. It was p0142 but i have a feeling the ypipe caused it.

check the O2 sensors for sure

What brand y-pipe and is it cali spec??

It'll return in about 2 days.

So are you guys saying that if it an O2 sensor issue, its just a matter of replacing it? Or is this a bigger issue? Sorry, I'm ignorant, but would like know more about this for when I get my y-pipe.....

After I installed my Cattman Y-pipe, my SES light also went on. I bought an o2 simulator and plan to install it rather than getting another o2 sensor. I did reset the SES light several times and still comes back on.

when something hurts and you call your doctor, do you ask him to tell you what's wrong with you by just telling him that something hurts?

just get the code read and then go from there.

your o2 sesnor is not nessicarly bad it's getting high voltage because of you y-pipe even if u set ur ECU it will come back in 2 or 3 days i hears some people say u can get a new o2 sesnor and it might fix it some say it doesnt help at all the light comes back on. but it's defently because of ur y-pipe good luck

It's a Cattmann supposedly. And it's a 2000 Fed spec.
I'm going to get the code pulled. But I may end up putting the stock Y-pipe back on.

i put my stock y pipe on my 2k max fed. and the ses light still comes on. i reset it like 3 times. also, the obd2 scanner said that it was high voltage/slow response on bank 1 sensor 2, so im guessing the 2nd o2 sensor on the y-pipe. anyway, i bought another o2 sensor and will be putting it in soon, but is it really the ypipe that is messing it up?

Cant beleive this thread is here. After 3 weeks from my y-pipe install, my SES light comes on and I was wanting to post a thread. Thinkin o2 also, i'm autozoning and bringing to my muffler man. Which o2 needs to be replaced? U GUYS R GREAT!!

And by the way, i dont hear the same swoooosh i used to hear with my warpspeed when i first installed it. I'm noticing puttering on accelleration between 1-3 rpm. Could it be the fitment with the warpspeed? But if u cattman guys also have this, hey. Whats my price for an o2, group deal? I have a 2000, too!

bout to go to autozone -what codes will tell me which o2 to replace? I have 3 (cali).

they should print out a receipt on which sensor it is .... ie bank 1 sensor 2 which is the one mine went crazy on..... i not sure exactly where it is... i think its the 2nd sensor on the ypipe, but not sure...

Doesn't putting on an aftermarket Y-pipe eliminate the stock pre-cats? If so, won't you always get a CEL since the rear o2 sensors will "know" the precats are "gone"?

Well I went to Autozone today and the scanner pulled up a misfire code. Before I went there I was sitting in line at the bank and felt the car misfire. This weekend I'm going to check the plugs and see if any are fouled up.

Well, without doing anything, my SES light turned off by itself. Its been a week with no return. I do recognize my mileage has increased nicely tho. Was the computer learning?

not on cali spec cars. the second o2 sensor of bank 2, firewall, gets put inline with the exhaust coming out of bank1 (radiator) to trick the ECU into thinking the rear bank is acting fine (just like bank 1) which still has its precat on the car.

I heard with the 5.5 gens (Fed spec), the pre-cats aren't removed when ya install a y..... anyone?

I changed my plugs and I still seel it misfiring every now and then. I think I might have to change out the coils next. The only other thing would be the O2 sensors. I'm going to be removing my y-pipe so I may just change the o2 sensors while I'm there.

hey man if there was a misfire the ecm would know sometimes you just get a vibration out of changing the y pipe for some reason. the ecm will either throw a single cylinder misfire code, or a multiple cylinder misfire code. the main reason the ses light comes on is because of the incredible increase in hydrocarbon emissions that are created with a misfire, that or NOX emissions which are caused by incredibly hot combustion chamber temperatures (lean misfires) just thought id let you know before you go and spend alot of money on some stuff you dont need.......dont throw parts at a problem cause then when you figure out what the problem is you cant afford to fix it.

Do you think that if I swap my Y-pipe back to stock it will go away?

I see ya gave up and are selling the y-pipe now.... its too bad things didn't work out with that....

Get an O2 simulator and don't worry about it

How much are those and how hard/easy are they to install?

My main reason for getting rid of the Y-pipe is the deep growl it puts out. It's just too loud for my taste. I do feel the performance increase, but it's not worth the sound I want to put out. I have to work out of my car for a little while until I can get a truck. And pulling up to a potential customer with a loud car doesn't go off too well on a business point of view.

Didn't say I was getting rid of the Max!
Just need a truck for work.

With The 02 simulator, you still wont be able to pass smog, because when they scan for codes before Smog, It will Still sayy what the problem iss..

Well then get more customers who are car enthusiasts ... j/k...

I know where you're coming from though... the Max is still a great car stock... enjoy it...

So is there any remedy for this in terms of smog testing or tripping a CEL?

Oh but wait, you're in Cali.... might be different out here East....