scanner for 1992 pathfinder?

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scanner for 1992 pathfinder?

Postby PattiM » Tue Jan 18, 2022 8:34 pm

I have a 1992 Pathfinder 6 cylinder 4x4 and was wondering if there's a reliable OBD tool for reading computer errors (like bad sensors)? It suddenly started running rough all the time. For a few years before that, it would suddenly run rough for a few minutes - maybe up to 10 minutes - once or twice per year. A full tuneup didn't help, but I couldn't really tell because it ran fine 99% of the time. I am wondering if some sensor or rubber hose can cause this, and if an OBD reader might help.

Thank You!

PS: a mechanic told me the spark plugs and compression were fine

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Re: scanner for 1992 pathfinder?

Postby smj999smj » Fri Jan 21, 2022 1:51 am

The Nissan OBD system used in the WD21 Pathfinders wasn't as sophisticated as later, OBD II systems. The diagnostics are actually done using the red and green LED lights on the side of the ECM. Nissan did have a tool which was made by Kent-Moore and is obsolete; I actually have one. But all it does is allow you to do the same functions that you can do using the mode screw and LEDs on the ECM remotely and without having to pull the passenger seat. 1992 will likely have a 5-mode ECM. Mode I allows you to see the O2 sensor response using the green LED flashes. Mode II shows the ECM response to those O2 sensor signals. Mode III is self diagnostic codes. Modes IV and V I didn't use too much. I know one of them shows present time diagnostics that will signal when a diagnostic concern is currently happening, like during a road test. The info is in the factory service manual and also at this link:

The kind of monitoring you're looking for didn't come out until OBD II in the R50 Pathfinder.

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