O2 sensor testing, need some guidance…

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11-07-2005, 09:52 AM

I30TinME

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O2 sensor testing, need some guidance…

After replacing my y-pipe I am getting a code of 0412, or O2 sensor, right bank. Now I have tested the sensor for resistance between the outer terminals and it read within specs (2.3-4.3 ohms), then I tested for continuity between the center and each outside terminal, continuity didn’t exist (this is good). Now which terminal(s) do you test for the voltage fluctuation? I am aware you need to bring the engine up to temp, under no load at 2K rpm and the voltage should change more than 5 times in 10 seconds and range between 0-0.3V <-> 0.6-1.0V, but I am not certain which terminals you should check. Can anyone advise, please?

11-07-2005, 05:10 PM

I30TinME

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Bump....and thanks.

11-07-2005, 05:22 PM

njmodi

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I can't find the exact terminal on the 02 sensor itself - but the signal wire from the o2 sensors goes to ECM pin 50... check between ECM pin 50 and engine ground (ECM pin 25)... as you mentioned RPMs at 2k constant, no load.

11-07-2005, 07:23 PM

I30TinME

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Thanks for the info. Yeah, I have a digital copy of the FSM and it goes into painful detail but never describes the actual plug on the O2 sensor side. On that connector, the two outside leads are white with the center lead being black. Now in one of the diagrams that show what must be the ECM side of the plug with the three wires listed as R/B, L/Y and W. I think it shows the wire (W) on the ECM side going to the port 50 on the ECM. If so, it lines up with the center lead on the sensor side. Looks like I will spend some time under the hood tomorrow.