I have a 97 dodge neon that has a 2.0 DOHC engine with one oxygen sensor after the cat. I have been getting this code no activity to this sensor and i put it on ramps and started looking, i noticed the oxygen sensor looks brand new and wen i looked at the plug to the car harness i noticed two of the wires had been split where as if someone had tried testing them and taped them back together. i got my voltage tester out to see if i was getting 12v to the heater which i didnt and cant find any good information on the internet about this i traced the green/orange wire all the way back to the fuse box under the hood and pinned it there and still no voltage, i also swapped relays out thinking it could be a faulty relay. what do i do now? is it a bad PCM? the pcm had been updated on november of 2000 so i would assume it wouldnt be that as this is the only problem ive had please help

 

also i think this is the cause of my annoying cold start issues, wen its cold it will not idle it sounds like its misfiring and once i get it warmed up itll smooth out and idle correctly every once in a while it will die as i clutch it coming to a stop though even when warm, i changed plugs with new ngks new fuel filter air filter changed oil and still having this idle issue

 

in the manual the dg/og wire looks like it shares power with the automatic shutdown relay, the manual shows a splice but for the life of me cant find location in this book of that splice.the pin out from the PCM is pin 6 in C1 for the dg/og wire. both oxygen sensors use the same power source dg/og wires. I would check the pcm for out put at the pin.

 

the book also shows that the gnds are through the pcm both o2 sensors and the battery temp sensor are on the same circuit or pinout pin43 at c2 bk/lb wire. i would check the pcm for gnd output if you have gnd at pcm more than likely the bk/lb wire is corroded and broke somewhere. I had a similar problem with electric fans and thought pcm, but it was the wire going down to the relay which was a gnd from pcm.

 

you are correct, the main harness running by the motor to the o2's are right beside the head it is notorious for overheating and melting them together, there i found the main ground to the o2s it was pulled apart from motor moving under the torque, i spliced and redone checked the other wires in the harness "i had to use a butter knife to split them from heating and melting together" and made sure no more had been hurt. after that i have no o2 lites!! now though i get a random egr lite and it still doesnt idle at cold start and random stop lites which i would be guessing that since the o2s been out for so long it caused alot of build up in the intake and my IAC and EGR need to be cleaned. anyone correct me if i am wrong but i think we have figured it out!.....why would anyone run wiring right beside the head of a car beats me! the easy fix is to splice and add a bit of wire in all the wires of the harness giving it more play and taking you mount for the wires and pushing it at least 1 inch away from the head

 

also check ur motor mounts mine was bad which would cause your motor to rotate JUST enough that it wud set the harness right ontop of the head making it stretch and get really hot. a simple fix, mine was the front mount and its almost impossible to tell if the rear mount is out because it is a "strut" type, my front mount will be in within a week and i will be sure to repost if my rear mount is the problem to save you from replacing both.