General Maintenance & Repairs - new o2 sensor still throws code

i just installed a new passenger side rear o2 sensor because i had a code p0157 low voltage bank 2 sensor 2 drove about 50 miles and then it threw that same code what else could it be bad sensor from factory or what? any help is appreciated

Did you look at the wiring? Could be crushed/crimped/broken.

You're still running stock exhaust with cats right?

wires are fine but cats are gutted with spark plug foulers in them the driver side works just fine with the foulers in

hmm. Why not just get 02 sims? The rear 02's aren't affecting performance anyway.

Why did you waste your money even buying the post cat O2 when it serves no purpose with your gutted cats? Of course it's going to throw a code since you have gutted cats. That sensor just lets you know when your cat is out. And your cat is out so it's letting you know.

i put foulers in it so it wouldnt do it the light was on befor the cats was gutted and the driver side is still workin

Go ahead and get the eliminators. They work. And you can get rid of rears all together. Save it in case the front goes out.

Sounds like a wiring issue.

Common mistake! DO NOT ASSUME that a code = a repair!! A code is only a start! To assume that a code = a repair is a NEWB thing to do.

Sounds like a wiring issue.

Common mistake! DO NOT ASSUME that a code = a repair!! A code is only a start! To assume that a code = a repair is a NEWB thing to do.

No it doesn't. Sounds like he gutted the cats and nothing is wrong. And why would assuming that a code equals a repair be a newb thign to do? As far as I'm concerned, throwing codes never meant something amazing has happened to your car...

To OP: Nonfoulers will not help. They do exactly what they're called. They don't let the plug foul. Now if you can get some Code Nonthrowers, A.K.A. O2 simulators, you'll be good to go. ;)

Spend some cash get a cam/springs and just get it tuned plug the holes and save them for later

O2 codes don't necessarily mean that the sensor is bad.

If I recall correctly, I got that code from a dirty MAF. A dirty MAF can cause the air reading to be artificially low, triggering the computer to make you lean. Which, in turn, can cause the O2 voltage to go out of bounds.

If this is your case, you'll probably also notice some hesitation in the engine under heavy accelearation.

it runs good and today it went off for awhile then came back on under normal driving i just cleaned maf sensor and filter. if the foulers dont work y has not the driver side threw a code after 10k miles. i think it is a wiring prob so what do i check im sure the o2 wiring is ok so were does the rest of the wiring go and will the o2 sims fix it even if the wiring is messed up the wire look visually ok but i havent looked real good

If you have one bad sensor and have a true emissions problem, its possible that the good one is the one giving you the code. That being said, when I had my MAF problem, I did get codes from both sides. (A P0137 and P0157)

If you can get a hold of a scan tool/software that maps out the O2 sensor waveforms, you should be able to see very easily if the two are off from each other or if one is flat-lining on you.

so does that mean the o2 sensor that i just put in is good and the one not throwing a code is bad.

It means maybe - but as stated earlier in the thread, you don't need the rear sensors if you have the CATs removed. They are just there to monitor the CATs and their performance.

The only way to tell for sure if a sensor is on the fritz is to get a tool that can show you the waveforms being put out by the sensors. (Which is a bit of an investment.) It could be a wiring problem and GM has a special procedure in the factory manual for confirming a wiring issue - but you need a scan tool that can read the sensors.

I would suggest that you first see how your clean filters and MAF do for you. From my experience, it seems that the MAF readings are dominant over all the O2 sensor readings, which is why I suggest trying them first. (Its also a cheap and easy thing to do.)

If it was my car I would have the rear O2's simmed. There's no reason to have that sensor there when your cats are gutted.

okay were can i get some cheap sims
but if it was a wiring problem would the sims work?

it runs good and today it went off for awhile then came back on under normal driving i just cleaned maf sensor and filter. if the foulers dont work y has not the driver side threw a code after 10k miles. i think it is a wiring prob so what do i check im sure the o2 wiring is ok so were does the rest of the wiring go and will the o2 sims fix it even if the wiring is messed up the wire look visually ok but i havent looked real good

I have no idea why the driver's side didn't throw a code. Maybe whoever scanned it didn't scroll down the list. :eyes: Do you know someone who can tune the car?

Check on the for sale section here or on ebay. You can usually find them for $50-60 for the pair.

ill just get some sims or get it tuned