95 neon keeps dying, please help

[rustycraig]

I have a 95 neon soc automatic. Was driving down the road the other day and the car just stalled a few times and died. Threw a trouble code for an o2 sensor. Replaced o2 sensor in bank 2 (near cat). Few days later same thing, died a few times, drove to autozone and got a code for ignition system.. replaced coil and it still didn't fix the problem. Within the last six months I have replaced the computer, coil, both 02 sensors, purge
canister valve, fuel pump, and plugs/wires. It still isn't fixed. Died three times yesterday while driving in the city and threw two codes: 12 (battery disconnect not relevent) 21: Problem with oxygen sensor signal circuit. Sensor voltage to computer not fluctuating. I could have recieved a bad oxygen sensor but can an o2 sensor really make the car die completely? Is it possible for a fuel problem (water in fuel, faulty fuel pump) to cause an engine code light to come one? The car runs fine, has plenty of power and then all the sudden light comes on and chug chug, die. Then it starts back up usually on the first try. Any info would help.

[denisond3]

I had a bad wire in the engine wiring harness on our 97 Neon. It is the harness that runs from the PCM, around in front to the injectors, - and around the back of the engine and down, to the cam position sensor, the crank position sensor (CPS), the alternator, the oil pressure sensor -- and to both of the O2 sensors. It could be one of the wires for the heater in the O2 sensor is shorting to ground (or to another wire in the harness). That same voltage is needed for the CPS (crankshaft position sensor). That wiring harness was badly melted on mine, and I finally replaced 12 of the wires in it. (Took it off the car to do this). Since then I have also had the wire to the O2 sensor short out due to rubbing against the body in one spot; but that was easy to fix.
While its messy to work under the cars in this area, it may be what is causing your engine to die.
Be careful with the wiring harness! While you can buy a new one from a Dodge dealer, they are about $800. !!
Maybe if enough of us go into auto parts places and -repeatedly- ask to buy an engine wiring harness, the aftermarket folks will begin to make them - for a lot less than $800. I make it point to ask each time I go into an auto parts place where they dont already know me.
Good Luck....

[discnik]

Code 12: Battery has been disconnected causing some learned values to be lost.

Code 21: Front or Rear oxygen sensor signal voltage was either too low indicating a short to ground or too high indicating a short to voltage.

Given these two codes it sounds like denisond3 has the right of it. Definately check that wiring harness.

Good Luck

[Oldsmobile Doctor]

The wire for the down stream O2 sensor on my 95 came off the bracket behind the alternator than fell onto the axle and rubbed the insulation off the wire shorting the dark green/orange wire to ground