Can someone tell me the color coding and the place where I can measure all three O2 sensor voltages on my truck. Back probing would be best. ECM is indicating that all three O2 sensors are not responding. Replaced all three O2 Sensors, nothing changed. Getting P1151 and lack of HO2S21 Switches. Also seeing Bank 1 Sensor 1 0Mv, Bank1 Sensor 2 0Mv, and Bank 2 Sensor 1 0Mv.
Using a AutoTap Scanner for the ECM Code Read Back. Long term fuel trim is also at -100%. Truck runs ok, idles a little rough.

 

P1151 is a lean code from the upstream O-2 sensor on bank 2. If thats the only code you are getting, i think you should be looking for a vacuum leak.

 

ashorn, did you get your problem figured out yet? this is my first post here, but i have been frequenting other ranger boards for a looong time. i am in the process of reading through all posts and i ran into yours which mentions some of the same obdii issues that you mentioned, namely 0v for all my oxygen sensors and both short and long term fuel trim values staying at -100%, using my Autoxray scanner to view realtime engine data. however, i have no codes showing and all is running fine?? any insight?

chad

 

Chad,
I have the same O2 sensor problem and fuel trim readings as yours and am baffled. Did you find the answer yet??
Don

 

nope, never got an answer or figured anything out. again, i'm NOT getting any codes nor does the engine seem to have any running problems ?? i just worry about having to get its first obdii emissions test which isn't due until september though and seeing if it fails for not responding?? anyone else any input??


chad