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Originally Posted by AtlantaBoxster
paulv
Yes, the O2 sensors are still swapped. I did not move them back. Since I switched all the O2 sensors, I did remove and put back the harness. If the harness was not seated properly, would I get a P0430 code or something else?
Just ordered this little jobby. Will see how well it works. Only $38 bucks, worth the risk. Seemed fairly decent reviews.
I'll let you know the results after I test it.
http://www.amazon.com/Crescent-OBD2-Multi-Protocol-Diagnostic-Scanner/dp/B001MT0XPK |
O2 sensors send signals back to the DME module. If the DME doesn't receive a [proper] signal, then a code will be generated. The only reason that there's a rear O2 sensor is to measure the cat conv's efficiency (under OBD2, not part of OBD1) -- the efficiency is the measure of how well the cat conv stores oxygen. Typically, the DME will look at the signals from both the fore and aft O2 sensors in order to determine if the aft O2 sensor is telling the "truth" -- thus, this is what Jager was talking about and is also in the diagnosis conditions I posted earlier.
As O2 sensors age, they get "lazy" -- which means that they don't switch as fast as they used to -- this would also generate the P0430 code.
If you have access to a graphing multimeter (or preferably an oscilloscope) you can watch the voltage signal coming out of the O2 sensor (and compare both banks) to isolate whether the O2 sensor is on the borderline of failing or it it's something else.
Also, I don't know if your year model has an O2 sensor as the fore sensor or if it has an air/fuel ratio sensor (aka: wideband O2 sensor) -- these don't have a switching voltage but they generate a current that changes polarity whether the mixture is rich or lean and stay at zero when the mixture is at the proper 14.7:1 (air to fuel). Some scan tools will convert this current to a voltage so it can be viewed easier, but not all scan tools do this.
Also, send me a PM with your email so I can send you the diags document (where I got the info to post earlier) and a DIY tutorial from a company that makes scan tools -- it's a nice intro to all this stuff. Can't post either here -- the diags doc is copyrighted and the DIY tutorial is too large.
What year is your car? I'll check to see if there's a TSB out on this issue.
Regards,
paul...