Code P0135 occurs when the ECU tests the upstream heated oxygen sensor’s heater circuit on Bank 1 and detects a short in the circuit or excessive resistance in the heater circuit. Looks like the top sensor may be bad; first make sure the harness connector is tight. When replacing sensors, always use Nissan OEM parts from a Nissan dealer; aftermarket electronic items generally are not reliable, don't last long, and many times are DOA. The sensors are not very expensive; around $75.

 

Thank you i just bought a VOM today.....As i said i just put 2 new sensors in

 

Thank you....funny thing is i have 2 new sensors in it

 

Something is wacky with your ECM or your code reader, or this post is in the wrong section. Rogo is right about P0135 being an HO2S heater code, but it doesn't have any application for an '02~'06 Altima with either engine package. If your ECM is throwing it then I'm afraid it's cuckoo.

 

what i want to know is how to check the wiring from the motor not the sensor and the values of pin 1.2.3.4 to see if it is the ecm

 

I'll try it again today........First time i checked it it was a 0420 code ......i replaced the cat.....then it popped up with the 0135 code

 

You sure it wasn't a P0138 and not P0135? P0138 is common with aftermarket rear O2's and aftermarket cats. If that's it, with a new cat I'd say put a spacer on the sensor to kill the code and forget about it.