I just replaced the downstream oxygen sensor with a denso universal and I got this code. I was worried about having the two black wires backwards when I wired it up could this be the problem? I followed the diagram but there was no way to distinguish the difference between the two black wires. Anything else I should look at?

 

Just curious, do you have an aftermarket full exhaust w/o cats? or gutted cats?
Because the p0141 is the heater circuit for the 02, and if you are missing youre cats or gutted them it's hard for them to heat up....causing the code to come on.

Also, if you do have cats, might want to recheck the wiring assuming the sensor works since it's new.

 

the black wires it makes no difference which is which.
make sure there is 10-40 ohms across the black wires with the O2 disconnected. (reading the O2)
make sure there is 12V on one of the wires going into the black wires[black/yellow] (reading the harness)
make sure that the other black wire runs to A6 at the ECU. [black/white] (reading the harness)

 

Ok I'll check it all that out Relic1.

And no full exhaust. Greddy SP2 catback /w stock header and cat.