O2 Sensor Wiring Diagram

[NiNeTy Fo SHO]

Does anyone have any wiring diagrams showing how the O2 sensors are wired into the car. I am specifically looking for the wiring for the O2 sensors pre-heating.

I am wondering if it is somehow tied into the CCRM...with a relay module in there that turns on the pre-heating line when its XX degrees cold outside.

Thanks for any and all info.

 

[hawkeye18]

The pre-heat line is activated with the IGN switch in RUN. It's directly wired through C1008/1009 and C103 to a splice off fuse #5. It's a purple wire with an orange stripe that provides power.

So, to answer your question, I guess if you want to preheat the sensors, just leave the switch in RUN for a few seconds before you turn the car on if it's cold out . It's a good idea anyway, to let the fuel pump prime.

 

[NiNeTy Fo SHO]

I have a problem with fuse #5 blowing. I know the O2's are wired to fuse 5 and thats why I wanted to know how they are wired in.

I know power comes from fuse 5...but then where does it go? I am guessing it doesnt go directly to the O2's...its almost gotta make a stop somewhere to trigger a relay to get mo powa to heat the O2's.

My fuse 5 runs fine...until I start the car when its cold, then fuse 5 blows. I am thinking the relay controlling the O2's has shorted out causing my problem.

Also, I get codes thrown when its cold out saying my O2's are out of range or something...but hte CE light goes off as soon as the car gets into the warm area...telling me the pre-heating is not working. Over the summer, I have reset the computer and have got no codes...but I know once it gets cold, the CE light will come on saying both O2's are crap...until the car gets warm..then they are good.

 

[SHOZ123]

No relay, power goes straight to the sensors from the fuse. Maybe a bad O2 or chafed wire?

 

[NiNeTy Fo SHO]

No relay, power goes straight to the sensors from the fuse. Maybe a bad O2 or chafed wire?

I thought a bad O2 was the problem also. I have replaced both O2's with brand new ones from Autozone. (whatever was recommended on this site for like $38.99 each) I checked the wires and nothing seems to be pinched/cut/sliced/etc. that I can see. I had this problem with the old O2's when they were working just find before Fuse #5 started going.

I know you have been around here for some time, but my gut feeling is telling me this:

With the car off and the key in the "on" position, fuse 5 works great. (tested for 10+ minutes) - Turn signals, reverse lights, EATC, everything that is on that fuse that I know of besides the O2's. (I dont know if they are working or not.) I start the car, everything works for about 2 seconds and then the fuse blows. I am thinking the car somehow knows when it is running and when its not so that it knows when to start pre-heating the O2's.

 

[SHOZ123]

Yes the car knows when it is running...

I would disconnect one of the O2s and see if the fuse holds. If it does I would unplug that one and try the other one by itself. Could be the wires going to the O2 plug too.

 

[NiNeTy Fo SHO]

Yes the car knows when it is running...

I would disconnect one of the O2s and see if the fuse holds. If it does I would unplug that one and try the other one by itself. Could be the wires going to the O2 plug too.

I will try this and see where it gets me. I have a strong feeling that the short is not in the O2's themselves, but in the wiring or in some relay/switch (if there is one in the line).