02 Sensor Prolems

[Intrepidman]

My 2002 Trans Am has been getting bad gas mileage lately and now its idle is getting bad and its stalling out. Finally the check engine light tripped and according to my buddy's hand held scanner its giving me a code PO 140 which he translated to mean a problem with the driver side 02 sensor.

Since I have a full exhuast my rear? o2s have been removed and tuned out for years now, but I'm wondering if one of them will be a suitable replacement for the front 02 that has gone bad.

Does anyone know if this is the case, or are they different sensors?

[thearborbarber]

You are good to go to use the ones you removed.

[35th-ANV-SS]

Is the harness length and connectors the same on front to back for our cars?

[98maro]

My car is throwing that code p040
I was told is the cat on the passenger side
So is that the
Cat or o2sensor?

[Cutlass]

p0140 is the driver's side rear O2 sensor. You can tune that code out.
And yes the front and rear O2 sensors on our cars are the same.

[0rion]

My 2002 Trans Am has been getting bad gas mileage lately and now its idle is getting bad and its stalling out. Finally the check engine light tripped and according to my buddy's hand held scanner its giving me a code PO 140 which he translated to mean a problem with the driver side 02 sensor.

Since I have a full exhuast my rear? o2s have been removed and tuned out for years now, but I'm wondering if one of them will be a suitable replacement for the front 02 that has gone bad.

Does anyone know if this is the case, or are they different sensors?

140 is a rear O2 code and should've been turned off with your tune. It also won't effect your idle or fueling. How many miles are on your front sensors? They could be drifting or I would probably start out by cleaning your MAF sensor.

My car is throwing that code p040
I was told is the cat on the passenger side
So is that the
Cat or o2sensor?

I'm going to guess you left a number out of that code. It's either 420 (drivers side cat) or 430 (passenger side cat).

[98maro]

I remember it's a po40 but I could be wrong

In case is the cat messed up
It's making a noyse anyway
I can replace it with a stock cat right?
Or any problems if I do dat?

[Intrepidman]

I'm suddenly confused. If code PO140 is the REAR oxygen sensor then I can't see how I'm getting that code. Way back when I had the full exhaust put on the car I had it dyno tuned and the rear sensors completely removed, and presumably tuned out (otherwise I would have been having a code all this time)

So how is it that I am having a rear sensor code now??


BTW, I keep my Maf pretty clean...whenever my idle gets a little rough I clean out the intake and spray the maf with a some non residue sensor cleanor.

The rough idle I have now is when the RPMs drop down to 500 or so and the car trys to stall out. It seems to be related to the code as shortly after I usually get this engine light.



One other thing of note, my dealer swears the front driver's side 02 sensor is a different part # than either of the spare rear sensors I have.....could this just be the length of the harness or something insignificant like that?

[35th-ANV-SS]

That is very weird, but yes P0140 is the rear O2. Are you sure his hand held gave you the correct code? Maybe take it to Autozone or Pepboys and have them scan it for you for free to see if they get the same code.

[Cutlass]

One other thing of note, my dealer swears the front driver's side 02 sensor is a different part # than either of the spare rear sensors I have.....could this just be the length of the harness or something insignificant like that?

Hmm...could be different lengths. I'm 99% sure the connectors are the same.

[0rion]

yeah, you can swap front to back.

[98maro]

My car is throwin up the code p430
I thought it was p040
So I need a new passenger side cat

I was told by my mechanic
ThAt I can not use a used cat
It still won't pass the smog it has to be new
Is it true?

[00ls-1]

My car is throwin up the code p430
I thought it was p040
So I need a new passenger side cat

I was told by my mechanic
ThAt I can not use a used cat
It still won't pass the smog it has to be new
Is it true?

i think he wants to sell a cat if it worked when it came off itll work if it gets put back on

[98maro]

That's way I thought if the Cat is fine it shouldn't be a problem
But he said don't waiste your money it will not work
So now idk

[00ls-1]

ive seen used ones put on the muffler shop used to use saved the old ones and sold them real cheap if someone had one break apart on the inside