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Codes - is this another code for o2 sensor?

Posted: Tue Feb 10, 2009 1:46 pm
by kc2005ptgt
P0138 HO2S Circuit High Voltage Bank 1 Sensor 2
P0140 HO2S Circuit Insufficient Activity Bank 1 Sensor 2

Pulled both those the other day - I assume it is o2 - but which one? I have been having a few, small, minor issues with the ACR since rebuild, but I had this one time before. Does this mean one of the sensors is going kaput? I still have all my power like before... just wondering which sensor it is... upper or lower?

Posted: Tue Feb 10, 2009 2:04 pm
by MyNeonSaysHi
90% of the time an 02 sensor comes up it is not the 02 sensor. 02 sensors are designed very well nowadays. Its more than likely a vacuum leak or something emission related. Doubt its the 02 sensors though unless they are the original.

Are you catless?

Posted: Tue Feb 10, 2009 2:05 pm
by kc2005ptgt
catless... only got this code one other time, pulled o2 sensor (upper) cleaned it, put it back in, never came back.

EDIT: they are both original

Posted: Tue Feb 10, 2009 2:16 pm
by occasional demons
Sensor 2 should be the downstream. Might have died, since the PCM "sees" it not changing value. Or a wire is shorted.

Posted: Tue Feb 10, 2009 2:24 pm
by kc2005ptgt
ooooh... wire, good thing to check.

Posted: Tue Feb 10, 2009 11:01 pm
by MyNeonSaysHi
Yeah check the 02 sensor wire...