Originally posted by 99blacksesport:
Well, I have "fixed" my pre-cats, put in the MIL eliminators. When I drive on the highway, and the computer interrorgates the O2 sensors, I throw a CEL. The two codes I get are (definitions according to CEG, I have different definitions in the book that came with my scanner):
1) P0136 Downstream Heated Oxygen Sensor circuit fault - Bank No. 1. (My book says that P0136 means: Low voltage bank 1 sensor 1)
2) P0156 Downstream Heated Oxygen Sensor circuit fault - Bank No. 2. My book says that P0156 means: Low voltage bank 2 sensor 1)
I thought that the downstream O2 sensors should be putting out a low voltage, meaning that they are working right? What is the voltage supposed to be on a working downstream O2 sensor? Any ideas as to what I did wrong??? Thanks for the help! -Nick
First off, your book's comments are wrong. Downstream sensors are sensor #2, not #1. I don't know what a 'MIL Eliminator' is but I assume it feeds a signal to the downstream sensors simulating a 'good' precat? Looks like yours isn't working and the sensor is detecting a lot of extra air from a 'fixed' cat brick?? So it's stuck reading lean, which is a low voltage. The HEGO voltage range is 0.1-1 volt, .2 being a lean reading, .9 being a rich reading.
That's what happens when you try to mess with the system. Have fun fixing it.
