Okay guys help me out with this. I had my CEL on and I took it and had the code read. Bank 1 Sensor 1 circuit low was the code. Bought a new O2 from the dealership ($225 dollars worth) and the light went off. I think the sensor was bad, something was rattling in the old one. The car drove much better. Then about 30 miles later the CEL was back on but it still ran good. Could it be the rear sensor this time since I do have the MMW header? Has anybody had this problem? Cuz that's a lot of money to throw down the drain. Very disgusted!!! Could somebody help me out?

 

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all you have to do is buy two spark plug antifouler read the thread on cel fix and it will tell you what to do

antifouler goes in second o2 and should eliminate that code!

 

What if it's the sensor 1 code again? Then what? I may have just wasted $225!!

 

the reason why you threw a code in the first place... is becuase you have a header. i think you just wasted your money buying a new o2 my friend... you need to get a spark plug anti fouler and put it into the second o2 bank... that way both sensors will read about the same amount.

 

Terminology. "Bank 1 Sensor 1" is the Air/Fuel Ratio sensor that installs in your header. Looks like an O2 sensor but is a different part from the Heated Oxygen Sensor in the S-pipe, which is "Bank 1 Sensor 2".

If the AFR goes bad it's possible the ECU would go into limp mode, which would explain why your car ran better after the new one was installed.

If you put in a header without doing the anti-fouler you will throw a code for catalytic converter inefficiency. This will not put you in limp mode so all you will notice is the CEL.

Pull the new code to be sure of what your new fault is.

 

The first code was: Bank 1 Sensor 1. It WAS the AFR. I didn't waste my money. I got the second code read and it is bank 1 sensor 2. So I probably need to get the anti- fouler. But what does bank1sensor 2 circuit low mean?

 

Use the CEL code number to look it up here:

https://www.scionlife.com/tech/manual/?manual=tc05_0170

Doing the anti-fouler may clear this up. Always heard the anti-fouler prevented the "low cat conv. efficiency" code, but maybe this is another related condition.

 

Hmmm this is an oldasss thread but i was wondering do you know what caused yur first sensor to go bad?

 

i know what happened to my first upper sensor. snap !!!!

ouch 200 plus for a new one .
i wont make that mistake again! heat is your friend in that department!

 

Wait your first 02 sensor broke just becuz it got hot? So you didnt do your own error to cause it to break?

 

no no no i was taking it off with a o2 socket and it ripped the threads , half in the stock manifold half in my socket i guess i was a little to aggresive and did not use enough heat!

 

Heated up (and expanded) is not the way to go. Mine came off real easy cold + several applications of PB Blaster.

 

actually heat is the way to go since its two different alloys you want to heat it up and use pb blast because if you do it cold your more likely to strip or malle the threads!

i work on cars alot .

let me tell you that some o2 sensors would never come out without heat!
due to rust and such things getting in the threads!

 

Im going to listen to you, who broke your threads over someone who didnt? Rite....

 

be my guest i in no way am telling you how to do anything just stating my experiances with replacing 02 sensors.

to each his own!

just saying in my case heat works better for the cars ive worked on!

only have had a problem with mine maybe cuz i felt it was still new and didnt do it like i usually would do on older cars.

 

I C, well hopefully that doesnt happen to mine.

 

ill tell you what if you break it i hope your wallet has a couple of hundreds in it cuz the cost 200 plus dollars!!!!!!!!!!!!

ouch

 

Yeah the AFR sensor is not cheap, even at Sparks.

I researched the techniques before putting on my header ... some (not all) of the folks who removed it hot broke it, believe all those who waited & cooled down first didn't. I followed someone's advice by letting the engine cool down the first night & then first application of PB Blaster + tap with a wrench to supposedly help it penetrate into the threads (don't know if the tapping really makes any difference but it sounded good ). Next morning, more PB + tap, tap before breakfast. Couple hours later one more app and both sensors came off real easy with the O2 sensor wrench.

 

Wow the sensor is that hard to take out?

 

No, not hard at all. Some folks have cooled down and removed the sensors right away after just one app of PB Blaster.

I'm just the cautious type and this method sounded like the way to go. Since I planned on putting the header in on a Saturday morning, I just spent a few extra minutes the Friday night before spraying down the sensors.