billybob59

hey guys

yesterday i was over my friends house and my SES light came on, so i went to auto zone and had them read the codes for me and there was 2 both the same thing (02 sensors) bank 1 or something. he cleared the code and the light stayed off for bout 25miles and now its back so im guessing my sensors are bad. r they hard to replace? expensive? my car is 02 z28 m6 only mods are slp loud mouth, and slp CAI with lid and k&n filter. thanks for your replies in advance.

also will it hurt anything to drive it like this till i get it taken care of?

waiting2bl33d

no they aren't hard at all. and no it wont hurt anything to drive around with them.

billybob59

also another thing the sensors are of the headers (exhaust manifolds) correct? or are there some place else?

2001NBMZ28

Do you have the code(s)? You mean 2 codes for Bank 1, Sensor 1 or 2 codes for Bank 1, Sensor 2? Before replacing anything identify which 02(s) it is, might even be a bad cat or something depending on what the code is.

waiting2bl33d

yes very true. alot of times though the ECM will spit out two of the same codes which is what he might mean.

then to answer your question it will say either Bank 1 (or 2) Sensor 1 (or 2) if its in the bank 1 then it will be on the same side as clyinder number 1 if on bank two yes you guessed it the other side or the side that clyinder two is on then if its your first sensor it will be before the cats...if its the 2nd sensor then it will be the 2 that are on the y-pipe and they are very very easy to get to. hope that helps.

billybob59

ok i will have to get them to read it again for me before i buy the sensor. so lemme see if im understandin u right if it say the code is for example Bank 1 sensor 1 would that mean its on cylinder 1 side before the cat? and if it says bank 2 sensor 1 that would be the side with cylinder 2 before the cat? and if the second number was a 2 that would be the sensors on the y pipe?

sry for my dumb questions haha im new at this, but thank you for your help so far u guys are great

2K2WS6TA

iTrader: (2)

IIRC bank 1 is the drivers side, bank 2 is the passenger side
sensor 1 is the pre cat O2 sensor, and sensor 2 is the after cat one.
So bank1 sensor 1 would be the DS precat O2
FWIW the pre cat O2s are more critical for the cars performance (they help determine the air fuel ratio) the rear (sensor 2) O2 doesn't matter that much. it just measures the efficiency of the cat, so if it's the sensor, you can drive with that one bad (until you can afford to get it fixed) and it shouldn't affect the performance too badly

billybob59

ok well thank u very much the cost isnt a big deal i can pick one up next week sometime and put it in just didnt kno which one it was and now ya narrowed it down for me ill have them scan it again and then ill kno. as far as the performance issue i havent noticed any performance difference and the car is still runnin very strong so ill have that fixed next week. after i change it can i reset the SES light my self or do i need to go to auto zone to have it cleared out for me then? thanks man

Syxx613

iTrader: (8)

yeah and it wont hurt to have a miss or two, and have one bank of cylinders runnig either to rich or too lean. who cares right? this is if its the pre cat sensor. if its the after cat, the only job it does is makes sure the cat is alive and doing its job. unless u have a scan tool u wont be able to clear the codes.

billybob59

ok guys got the code read again to make sure before i purchased the sensor and the code was PO420 Bank 1 (catalyic something below minimum efficency threshold or somethin to that effect)?

any ideas? think my CAT is goin bad? i havent noticed a power decrease, the car is runnin like a raped ape, so im assuming this isnt a like major deal. so what should do u guys think is that cat bad? should i look into replacing it? i might just say the hell with replacing it and just get some headers and 02sims and a different y pipe and run with out cats cause i have a garage that will inspect it with out them. thanks for your input in advance.

2ndly is it ok to run it in this condition?

2001NBMZ28

Sounds like your drivers side cat - they're covered under the federal emissions warranry to 8 yrs/80K.

waiting2bl33d

since you seem to be just the master on the topic. if the o2 codes are telling the computer anything they are telling the computer that it is lean when an o2 goes bad which would mean that it would add fuel...which isn't "bad" its running rich but thats about it also if you understand how an o2 sensor works then you would relialize that it isn't bad to drive w/ a bad o2 sensor its not good for alot of reasons and the only NOTICABLE difference would be gas millage. but thats just my .02 cents take it or leave it

personally i would take mine to get convered by the extended warrenty and i would take care of the problem as soon as it comes up but all i was telling him/her was its not going to granade your car if you drive w/ it.

billybob59

basically i dont think im gonna get it fixed i think i just may go ahead and get some lts and an ory and be done with it. these were future mod plans but this just may be the excuse i needed lol. but im just up in the air right now and just wanted to know if it would be ok to drive for now till i make up my mind.

Super Speed

iTrader: (8)

Its ok to drive around with em you will notice a drop in mpg though thats for sure