I know there are a few of you out there that have access to the online service documents, hopefully one of you will see this.

All I'm looking for are the locations of the rear o2 sensor (sensor 2) engine side harnesses. I won't get into details as I've already got other threads about this but I suspect that car washes with underbody spray are causing water to infiltrate the harness for my Bank 1 Sensor 2 engine side harness causing a short to voltage intermittently until it dries out and I want to see if this harness is reachable without a lift or a yoga class membership so I can inspect it myself and maybe clean it out and throw some dielectric grease in there for good measure.

It's for 3GR-FSE but I'm sure 2GR-FSE is probably close enough if not identical.

Thanks.

 

Still looking for this... I thought I had the problem solved as I hadn't seen the O2 sensor high voltage code for months an months but I took the car through a wash yesterday, parked to get groceries and the check engine light came on on the drive home with this code again. I think the harness on the engine side for this rear O2 sensor is sometimes getting water inside when I get the high pressure underbody spray in the wash and I want to smear grease all over it but I still can't figure out which harness it is.

There are a bunch visible on the front passenger side of the engine which seem to have the right number of wires, if I can't dial in exactly which one I want then I guess I will just grease all the ones I can see but it would be helpful if I knew I got the right one or not in case it's somewhere that isn't in plain view.

 

See my other thread titled "DYI bible", it is a link to the entire service manual, go to electrical, location, it is body LHD after 2006 #4

directly accessible here the part location you are looking for is W45
that is for wiring harness

A clearer diagram is found in the service section, engine, SFI system, parts location here

 

Thanks, I hadn't seen that thread... a great find. That routing diagram does KIND OF help, well it isn't exactly precise but I can follow the purple noodle into what appears to be an area near the firewall on the driver side above the wheel well. This really looks like some place I probably won't be able to get to without removing the wheel well liner - which is a very ARRGH prospect when the only place to do it is my driveway and it's -20C outside. However the purple noodle kind of merges in with all sorts of other stuff so the only thing I have to go by is the note near the bottom that the connector I'm looking for may be grey.

Well, that isn't where I thought to look in the first place but it does stand to reason that would be an area that would be prone to getting wet. Thanks for the help!

 

I think it's K34.

 

Yeah, that's where the harness connects on the cabin side... it's where it goes in the engine bay to the main wiring harness but to be honest from that picture it appears as if there isn't another harness involved and that harness K34 is part of the main wiring harness so if any connector is getting wet it is somehow getting wet in the driver footwell by the stereo ... so how on earth would a car wash get water in that location!?

Unless there is some way that water can infiltrate the wiring exposed underneath the car I'm just not sure at this point how K34 could ever get wet (enough) from just a simple car wash to short the circuit. At this point I might just cough up the money and buy a new sensor for that side even though I really doubt it's the sensor itself (which has only like 5000 miles on it) and because of the fact that the code is water event related.

I don't know, I hate this stuff... last time I brought it to lexus they charged me the diagnostic fee just to tell me it's because of an exhaust leak well guess what I went through a car wash the day after I had the exhaust leak fixed and the code came back... so I am really wary of paying for a diagnosis on this again anywhere.