O2 sensor and ECU connector pin question

Dear Guys:

In my 96 Tacoma 5-speed 2RZ-FE, I get an OBD diagnostic showing
the Bank 1 Oxygen Sensor Number 2 reading to be stuck at 1.25. Unplugging it makes no difference. The service manual says this could be either a bad O2 sensor or a bad wiring harness. OK, I know how to check a cable with an ohmmeter, the only problem is the book doesn't tell me what connector pins at the ECU correspond with the pins at the O2 sensor. Does anyone know where I can find this out? Even better, is there some place I can get *all* the connector pin designations for the ECU? Any help would be gratefully appreciated!

Sincerely,
-- Lea

 

Seems like a good service manual should have the wiring diagrams in it. You may want to look in to Chilton (bottom of the line) or try Toyota directly.

 

Dear 007:

You would think so. I have both the Chilton's (not very useful) and the official
Toyota (costs over $100) service manuals, and as far as I can tell, neither has that info. If I may vent a little, the Toyota manual seems to have this sort of info for just about everything except the O2 sensors. If it's there, they've hidden it in a very obscure place.

Sincerely,

-- Lea

 

I wonder - is the O2 sensor separate from the wiring harness or is it considered all one unit. The reason I ask: if the wiring and the sensor are considered all inclusive, it may be that there is no standard (per toyota) since it is contracted outside of Toyota. Sorry I can't be more helpful.

 

Dear Mark:

Well, each sensor has a local connector to the part of the wiring harness that goes under the body of the truck. I think they are separate assemblies. Also, the parts can be ordered separately.

Sincerely,

-- Lea

 

Then I have no idea why the Toyota schematic/manual does not show them. I wish I had a copy in front of me to reference.

Again, sorry that I am not of much help.

 

Dear Mark:

I finally did find the wiring diagram I needed in the service manual. I had to back-track about six pages from where the DTC procedure pointed me. Not at all obvious. Thanks for your suggestion which prompted me to go back and check again. In case anyone is interested, here it is.

Sincerely,

-- Lea

 

Glad you got it all figured out!

Thanks for posting the wiring diagram.

 

if any of you guru smarties can figure out what the rear O2 sensors resistance is while running normal I'd really appreciate it so i could eliminate the rear o2 sensor and use a straight through cat