Question on oxygen sensors

Tony R · 10-13-2009, 05:54 PM

I know this a little OT for the classic section but I need to know if there is a way to test oxygen sensors to see which one is bad. My wife's car has 2 of them and the code only says that one is bad but not which one. I don't want to throw 80 bucks on a new sensor to find out it is still good.

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Starfury · 10-13-2009, 05:57 PM

The code won't exactly tell you that an O2 sensor is bad (unless it's a heater circuit). What it will tell you is what kind of problem the system is experiencing, as well as which bank/sensor is having a problem.

What code are you pulling? And what kind of car? What motor in said car?

There is a way to test O2 sensors, but you need expensive shop equipment (a lab scope, aka digital storage oscilloscope)

Tony R · 10-13-2009, 06:17 PM

It is on my wife's 96 (IIRC) Toyota paseo. Last time she tried to have it smoged it failed so she had it diagnosed and the mech told her that it was an 02 sensor. just wouldn't tell her what one unless she paid them. Pulling the battery cable usually clears the codes and allows it to pass. It is that time again to smog and I was wanting to try and fix it.

andrews4691 · 10-13-2009, 11:59 PM

take by a parts house that scans for free. bank 1 is cylinder 1 side. sensor 1 (upsteam) is before cat, sensor 2 (down stream) is after cat. Curtis