2001 Nissan Quest Can't pass inspection, no active DTC's

Tiny
RONAE
  • MEMBER
  • 2001 NISSAN QUEST
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 74,000 MILES
I've got a 2001 Nissan Quest with a 3.3L
A couple weeks before it was due for a NYS inspection, the battery shorted out and needed replacement.
Since then, and after approx 2000 miles, the Catalyst and O2 OBD-II status is still not ready.
Here's some details.
The engine running temp is over 180 F (on the road using an ODB scanner I see it range between 182 and 196). I looked for a replacement thermostat, and it was rated at 180. So the temp range appears to be normal, correct?

There has never been any Active DTC's, however a "pending" Knock Sensor shows up.

I ran an HO2S and Catalyst Drive Cycle several times.
IE: Idle till op temp achieved. Drive at 56MPH for 3~5 minutes. Decel for 10 seconds. Back to 56 MPH for 3~5 minutes. Decel to stop (keep running) Check readyness; Still not ready.

Looking at some other specs, the pre cat O2 has normal voltage and fluctuation.
The post cat reads 3 volts constantly, and I never saw any fluctuation while driving. BTW out of arguments sake I replaced the secondary 02, but realized after, it was not neccessary. The readings were the same with the original and new sensor.

This car recently drove some 1,400 miles -mostly highway. The Cat and O2 are still "not ready".

HELP!

Edit 9/8/10:

My bad, I forgot the decimal point. It is 0.30 volts (-0.5%).
I thought the max voltage an O2 sensor can create would be about 1.0 volt. If there was a + feeding short, then maybe it would read 5~12ish volts? Also I'd get a DTC then, yes?

Since there is no voltage fluctuation, it made me think maybe the heater part of the sensor isnt working right. But I thought that should push a DTC. Wouldn't it?

I'm going to try and disconnect the down-stream O2, and see if that gives me a code. Also I'm thinking I can ohm out/check continuity between the O2 sensor connector and the ECM. The reason I have hessitated to do any of this is due to the lack of trouble codes.
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Sunday, August 8th, 2010 AT 5:58 PM

5 Replies

Tiny
DR. HAGERTY
  • MEMBER
The state requirement is that all the monitors run to completion, correct? California law allows 2 monitors to be incomplete, is this similar to your state? My experience as a smog tech has shown that those two monitors are usually the most difficult to complete, especially if you are not at all sure of the requirements of the manufacturers drive cycle. Exceeding the parameters of the drive cycle will suspend the completion of the monitor until all the "dominoes" fall in order.
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Wednesday, August 11th, 2010 AT 9:18 AM
Tiny
RONAE
  • MEMBER
For New York City; prior to 2001, 2 "not readies" can pass. But for 2001 and up, only one is allowed.
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Wednesday, August 11th, 2010 AT 2:20 PM
Tiny
DR. HAGERTY
  • MEMBER
Thanks for the heads up on that, is there something else I can assist on as this seems like we at a standstill at the present.
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Saturday, August 14th, 2010 AT 4:43 PM
Tiny
RONAE
  • MEMBER
It turned out two wires on the four wire O2 were open in the harness. The black (ground) and the white (reference?) Broke near the harness connector at the end by the sensor.

Not having exerience with this situation, I was assuming such a thing would trip a DTC (or two). That's what threw me off.

After soldering the wires back together and insulating. I'm now getting the proper varied reading from the downstream O2.

Now hopefully I just drive the vehicle and get the status to change to ready.
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Sunday, August 15th, 2010 AT 12:18 PM
Tiny
DR. HAGERTY
  • MEMBER
I appreciate the feedback mate, drive it until the monitors complete, smog the car, and we will be here if you have another issue.
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Sunday, August 15th, 2010 AT 1:27 PM

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