Closed loop?

[kevins]

Finally got my top swap running and noticed it will not go into closed loop. Bank 1 sensor 1 is stuck at 456. I know that means its an open circuit prob. Since i bought the car as a pile of bolts in the trunk i dont know what is original or not.Some of the parts are off of an 06 lacrosse poss the o2 as well, will a newer model o2 read in a 97?

[dpzelenak]

yea it should how many wires were on it 4?

[SlowNA06]

yea it should how many wires were on it 4?

The 04+ Grand Prix O2 sensors are different from the 97-03's. Not a clue on a Lacrosse, though.

[dpzelenak]

the lacrosse should have a HO2S whitch has 4 wires and the 97-03's have the same, or as least my 02 does and i dont know why the 04+'s wouldn't have the same either they all use the same system

[kevins]

Correct me if i am wrong but if you take the signal wire (purple) from the o2 connector and ground it, shouldnt your o2 voltage change from 435mv to 0 ?

[dpzelenak]

yes but not putting it on a ground will do the same, so theres no need to ground it but if the pcm gets a 0v read(pre-cat) i think it'll throw a code sayin that the voltage is low on bank 1 sensor 1 or something like that...i think?

[kevins]

i dont think leaving it unplugged will do that because when unplugged the potential voltage is there untill its pulled low.

[dpzelenak]

yea on the ref wire it will but not the signal wire, it'll just read 0v if it not plugged in and the pcm will the something is wrong and set a code

[kevins]

while watching o2 data on the scan tool and shorting the purple wire to ground, my o2 mv reading never changes from 435mv. checked both wires from pcm to o2 and both are good and not shorted.

[dpzelenak]

did you see what it said when the wire wasnt grounded?

[kevins]

435mv

[dpzelenak]

so you made a open on the signal cirurit and its still reading like normal..right?

[kevins]

reads 435mv unplugged or grounded

[dpzelenak]

are you sure thats the right wire?
i dont know why it would be doing thatif the signal wire is unpluged then how does is the pcm getting a reading?..thats what i dont under stand

[kevins]

O2 voltage went to 880mv so i checked the ground (low) input from pcm. It was missing so i created a ground and they started working. Problem solved! I think ill leave the homemade ground instead of buying a new pcm.

[dpzelenak]

yea thats all ways cheaper and sometimes better then spending 3-4 bucks
glad that you got everything taken care of

[kevins]

So i'm not the type to let things die. I've worked at a gm dealer for a long time and hardly ever is it computer. So after doing more research I found that a oxygen sesnor from a newer (03 ish and up) vehicle will not work in an older vehicle like my 97. The wires are the same color and located in the same cavity. However the signal and ground of the sensor is reversed. Purchased an O2 for a 97 and all systems work as designed. Hopefully this may help someone in a sim.. situation one day.