Help with O2 Sensor wiring (1 Viewer)

[ariff]

So now that we have the LC running I checked the check engine light and got an error code 28 No.2 oxygen sensor/heater signal fault. I went to go look and see if there was anything obvious wrong and low and behold I found this.. Looks like someone or something has cut\chewed through the O2 Sensor wires. My question now is since there is not a connector on the end where does it connect? I see the harness for the other O2 sensor runs up the wheel well and becomes part of the main harness under the wiper motor. I do see an obvious connector that is not connected. If this missing connector is indeed the connection to the No.2 O2 sensor can anyone give me an idea of how the wires connect? What color to what color?
Thanks..

Chewed wires:

Connectors in engine bay:

 

[jfz80]

Are you sure that is #1 sensor loom? It very well may be, just curious

Ive recently worked on a couple harness removals (94 and 97 with slight differences) for HG work and thought both went down driver side by starter and then up and over the transmission to the O2 sensors.

Just a guess but dont think that is your connector and would kind of expect colors to match same colors but Cannot say for certain.

 

[ariff]

Well I am assuming it is since the no.1 O2 sensor plugs directly into that loom and I am not getting an error for the no.1 sensor on the CEL.. This is on a 93.. May be different than the 97? And I can't seem to find the electrical connection diagrams anywhere. They don't seem to be included with the FSM I downloaded here awhile back.

 

[Malleus]

I'd recommend having someone look at that skin condition...

 

[Malleus]

This is from my '94 FSM; I think the '93 and '94 share some DNA...

Looks like your sensor wiring is what's marked "Oxygen Sensor Right", if I read this correctly. But that's at odds with your code since this is the Number "1" sensor, and the "Oxygen Sensor Left" is the Number "2" sensor. Anyway it's note 1.(3):

O 4, O 5 HEATED OXYGEN SENSOR (OXYGEN SENSOR)
1 – 2, : 5.0– 6.5 Ohms
This is pages 58 & 54 (resp.) from the Engine Control EWD

 

[Malleus]

These are from the same EWD, it's split in the TIS:

HTH

 

[Malleus]

Lat two are the schematics:

 

[ariff]

I'd recommend having someone look at that skin condition...

Rust.. Yeah the camera flash makes it look much worse than it really is.. And It is on my list of things to fix.. Hell it was a free truck so I am not complaining ;>)

 

[ariff]

Thanks for the diagrams.. I am wondering if anyone with a 93 could check if this plug does indeed go to the O2 sensor maybe? Pictures of that would be really helpful.. Thanks!

 

[ariff]

Bump this post with hopes some one out there with a 93\94 can help me out with some pictures of if this connector actually plugs into the O2 sensor..
Thanks!

 

[Malleus]

@ariff, I meant to do this three times since your OP and was immediately distracted when I got home from work.

I'll crawl under my '94 this afternoon and drop you a line tonight.

 

[ariff]

I actually was able to look at a 93 last night.. It looks like the other end plugs into the harness on top of the transmission. Not sure how I am going to get access to it as I could barely fit my hand in there between the trans and floor. Also the 93 I looked at did not seem to have the mystery plug in the engine bay by the cruise control module.. I wonder if yours does? Thanks

 

[Malleus]

I'll look at that too. This post
Does anyone know what these unused plugs are in my engine bay?
had a similar question. Are these the plugs you see? You can't have an auto antenna in yours, I don't think.

I'll troll through the '94 FSM (I don't have a '93) and see if I can find something. More to follow.

 

[ariff]

No that is not the plug I am seeing or at least it does not look like the one in the pic I attached in this original post. My antenna is electric but not auto. Thanks for the help.. The electronic FSM PDF I have does not have the schematic for this.

 

[Malleus]

I stand (sit) corrected, again; there is an auto antenna option (in '94, I assume for '93 also). Look at "A9"

:

 

[ariff]

OK so I have a plug going to the antenna I am assuming that is the auto antenna A9.. Here are some more detailed pics of the plug and the wire colors.

 

[Malleus]

@ariff, here's what I have so far:

I have five photos of connectors on my '94, none of which match the EWD. I have some studying to do tonight, for my own education. More to follow.

However, I looked back through the EWD and your photos, and the
Orange,
Gray,
White,
Black w/Yellow tracer,
Light blue w/White tracer and
Yellow w/Red tracer
wires are the O2(1) and O2(2) sensor connector wires, according to page 58, engine control wiring diagram. The parts location diagram is sufficiently vague as to be no help to me (at the present).

Here's a thought which may be of some use to you. If you're actually missing a connection, this should ID it for you:

I believe this is the module/connector in the engine bay, near your orphan connector, labeled "DIAGNOSTIC". I'll open mine when I get home and verify the pinouts.

On the subject of the orphan connector adjacent to the Cruise Control module, I have the same connector, and do not have an auto-up motor/switch on my antenna.

 

[ariff]

Well after crawling around under the truck last night I found the other half of the chewed through O2 harness. It does indeed come from the trans wiring harness on the driver side. I have some soldering to do.. Dang mice.. From what you are saying your 94 has the same orphan connector that is not connected to anything by the CC module then.. If so I'll not worry about it.. Thanks for the help..

 

[Malleus]

Both my '94s O2 sensors plug into the harness on the passenger side. It's the part of the harness that dives out of the engine bay below, and to the passenger side of, the diagnostic port. The only driver's side connectors are on the transmission and transfer: A/T temp sensor, Transfer LO indicator, speed sensor and one other I haven't ID'd yet.

FWIW, you can access the connectors on top of the transmission through the opening in the tunnel. You'll have to remove the shifter trim over the tunnel, the carpet and unbolt the access panel.

HTH

 

[Malleus]

I just compared the '94 EWD with the '95 EWD (page 22). The '95 EWD component location diagram, matches my '94 and '95. The '94 EWD seems to describe yours. I forgot that my '94 is a November 1994 model, which I think makes it a (mostly) 1995. So that probably explains why my wiring locations didn't look right. Just thought I'd add that.