Zero/Fluctuating 02 voltages and a CEL

[awdclipse]

To begin, I did a six bolt swap everything was fine until I hooked up the 1g 02 sensor to the 2g harness and blew a sensor ground from mixing up the wires and it barely ran. I fixed the ECU and the car runs good now except I have a P0170 code which i did not have before I blew the ground.

I have a simulator on the rear sensor (which reads 0.00v) and the front 02 sensor reads zero on my logger almost all the time except every once and a while will throw random numbers. It doesn't cycle or anything. Replaced the sensor, and still have the same issue. A replacement ecu is all i can think of.

 

[impactspoon]

I would suggest starting off with the basics and checking the connection for any kind of corrosion, or anything that would not allow the signal to reach the ECU. It kind of sounds like a burnt wire from what you have described. To be sure this is the case, run the car and warm it up to operating temperature. Then, CAREFULLY disconnect the O2 sensor in question and check it's voltage with a voltmeter. If the voltage is constant, then your problem lies within your wiring harness/ECU. To trace it down from there you will need to find a pinout diagram for your ECU and test the wire itself. If the wire tests good, then I guess we both know the only thing left in the equation. DO MAKE SURE ALL YOUR GROUNDS ARE GOOD, in my experience almost any intermittent electrical problem can be traced down to a bad ground. Good luck and let me know how you make out.

 

[awdclipse]

Hey thanks for the response. When you say test the 02 sensor while it's at operating temperature, how will the sensor read constant voltage if it isn't connected? I think my problem lies in the circuit somewhere because I've tried two sensors with the same result. But hey maybe they are both bad?

 

[ghettoslide]

Did you find anything out? This is the exact same problem i am having i bought the car this way. I bought a brand new 02 sensor from auto zone. My local auto zone did not have it so i drove to the next one and picked it up. When i got home i installed it, erased the code and started the car only to have the cel come back on after about 3 min. Same issue, but mine reads po135, which is 02 sensor heater malfunction. Since the heater is internal to the 02 sensor i figure it is a bad sensor i take it back to my local auto zone and they order me a new one and give me back 21 dollars because i over payed for the first one. While waiting i changed the plugs, got the new sensor installed it and i am at the same problem.