front 02 sensor code?

[Allen fong]

Anyone know if a leak at my manifold and turbo would throw a CEL for the front o2 sensor? Just replaced the 02 sensor and cleared the code and ran it for 15 min then light came back on same code. I did however notice 1" crack on the 2G manifold and seem to be missing half the gasket between the manifold and the turbo. Anyway if i got a bad o2 i'd like to replace it now while the manifold is off. Or was it the gasket all along?!

[Dan Silburn]

I replaced that sensor before you bought it!. Are you sure it isnt for the second o2 sensor which I removed and replaced with the wideband?

[Allen fong]

no i turned that one off with ecuflash 

[John Hartman]

definately all that false air in the manifold can cause the O2 to read falsely.

But it could be other things tho.

[Allen fong]

Ok fixed the leak cleared the code and 15 min later its back on! New 02 and no exhaust leak...so going to look for a wire short!? any ideas John?

[Brett Haviland]

what is the exact code?

[Allen fong]

P0141

[John Hartman]

ahh, thats a rear O2 code not a front one!!  its a heater circuit code for the rear O2!!  Bank 1 sensor 2.  We only have one bank so thats self explanitory.  Sensor 2 is always the post cat/rear sensor.

[Allen fong]

I lied!   p0136 i actually decided to flash a different image to my ecu and didn't edit the periphery bits. so i had both and i didn't notice till now when i cleared my codes again.   NOOB

[Dan Silburn]

 

[John Hartman]

ok, so do you have a rear O2 sensor in place?  Lots of people don't have on, or have parts in place to fool the ECU, and sometimes they don't work perfectly.

if you have a fully working one in there maybe there is a problem.

if its a heater code, you need a new rear O2 sensor.

Now the only reason for a rear O2 is to monitor your catalyst, so if you have no cat, you don't need the rear O2, but you will have to disable the code in your software or always have a CEL on.

Personally I would run a good cat and run the sensor.  At least on a real street car.  Less headaches, no problems with aircare etc.

For a weekend warrior street car, maybe remove the rear sensor, the cat and disable the cel for that code, but make it so it can easily be put back it for aircare.

[Allen fong]

Ok so the rear o2 is replaced with my wideband and its turned off with software, however i do still have the PO136 code that keeps coming back on. if i clear the code the car doesn't seem to run very nice wideband is all over the place, but once the ecu throws a code P0136 it seem to run fine? Dan says he just replace the 02 not long ago and i just replace it so either i got a bad one or theres another problem. I did try to reflash my ecu thinking it maybe a bad flash however i got both code for front and rear o2. thats where the confusion came into play. Once this weather clears up i will check the wires and go from there.