Seeking help with Bosch universal O2 sensor wiring on Obd1 80 series. (1 Viewer)

[MrSmokey]

Hi folks, I'm reasonable sure I have this right but was looking for confirmation, as another member posted results in the past that claim what I am thinking is incorrect.

Correct me if I am wrong please.

HT1 orange HT2 grey, and +b (red/yellow)is the heater circuit?
polarity should not matter says Bosch.

Ox1 white with blue shielding, and Ox2 blue with blue shielding are the signal wires? So I shouldattach the black from the Bosch.

And then there is Ox+ , which should be black and yellow. which I think is where I connect the ground, only on the 80 it's not grounded like it is on the 60.
On the 60 those go straight to the E1, not ox+


The Bosch O2s grey wire is the ground, do I wire this up to the Ox+ black and yellow wires

Here is the Bosch instructions, and the 80 O2 diagram

And the 60 series diagram

 

[MrSmokey]

I have to throw in the towl for tonight, bat died in the DMM. Also, i forgot to state, the O2 i am trying to instal are the bosch 15728. The ones i pulled are NTK i put in 3 years ago, i had a bad leak near them though, and threw codes for both of them, and the heaters tested dead according to fsm.

I tried to check the ground on them to figure out how to wire the bosch ones, but i got a lot of resistance from both the blue and grey wire to the sensor body. on the bosch it has 1 ohm or so between its stated "ground" wire and the body....


How do you guys that have these working have them wired?

edit, i found this video which was super helpful if its correct, do yall concur with this info?
Toyota - Blue → Bosch- Black (MOST IMPORTANT)
Toyota - White →Bosch - White
Toyota- Brown → Bosch- White
Toyota - Grey → Bosch – Grey


he links this thread too O2 Sensor Replacement - 1994 FZJ80 - https://forum.ih8mud.com/threads/o2-sensor-replacement-1994-fzj80.118555/

i used the search function, and google many times before posting i promise.

 

[Malleus]

Rather than depending on YouTube, why not check the wiring in the EWD? Toyota doesn't publish YouTube videos.
This is from the 1994 EWD (you didn't specify what year you have):

The FSM/EWD is in the Resources section for free download.

Maybe we should rename that forum "don't look here", since apparently no one does anyway.

 

[MrSmokey]

Haha good guess, It is a us spec 94. Sorry about that, end of the day oversight.


So yes, the FSMs and EWD you and others have provided on here are a great resource. Im probably overlooking something but, even with that the wiring diagrams im still not certain which wires to use for the signal, and the ground. Toyota never intended for these O2 sensors to be used on this truck, but the original NTK are NLA. Other forum members have reported success with these bosch 15728 sensors.

Toyota does not specify which is the signal and which is the ground for the o2 on the diagram, both wires go to the ecm, but it has to either be ox1 or ox1+ (and ox2 and ox2+).
Im not sure if that + is for polarity, or for auxiliary, or what, however when i put the key on i get 12 volts from b+ (to ground), 1.02 volt from ox1+, and .79v from ht1, and 17.8mV from ox1.
That leads me to think they are referring to polarity, but im not sure, especially since ox1 is shielded and ox1+ is not.

Like i said before other members have posted conflicting results in regards to wiring the bosch univeral.

Here OX1+ is used for signal, and OX1 for ground and success is reported. post #11 and 12

O2 sensor wiring help

guys, need help i found that my outside cat o2 sensor is not hooked up anymore and that is why i'm getting a code 21 wheni read the codes, but the PO must have replaced broke off the plugs but neither the harness or the o2 sensor have plugs, and there was a weird connector device, the problem is...

forum.ih8mud.com

Here (and in the video i linked) OX1+ is used for ground and OX1 for signal and success is reported. with multiple follow ups for success, im assuming they wired it as he clearly states. post #1

O2 Sensor Replacement - 1994 FZJ80

Figured I'd share my research ansd R&R into 02 sensor replacement for the 93-95 (pre OBD II) trucks. After my bonzai trip out east with my tandem axle trailer to pick up the back half of a Honda CRV in MD, my SC toasted the original 02 sensors climbing the hills of WV. Bad idle, total crap...

forum.ih8mud.com

I don't know maybe it will work either way, but while its not the best reference because its an old sensor that was throwing codes with a heater that tested dead, non of the wire on my NGK NTK sensors had much continuity with ground at all, whereas the bosch ground wire has full continuity with the body of it.

the bosch sensors ground wire has full continuity (around one ohm) with its case, that would consequently be grounded to the engine when installed, It seems illogical for the OX1+ which was sending one 1.0 volts (with the ignition on) would be connected to it, when the OX1 was sending 17.8mv with the ignition on.

To further muddy this the 60 series has nearly the same layout as the 80 series for its o2s, ( refer to the pics in my first post) the schematic is near the same. But they wire what would be OX+ direct to ground.

Then again, OX1 and OX2 go up to the test connector, and not OX1+ or OX2+

I checked the number on the sensor, and they are the bosch 15728


So, is OX1 or OX1+ the wire that should be wired to the bosch's ground wire?


What do yall think?
Help would be greatly appreciated!

 

[MrSmokey]

For the TLDR crowd. Is OX1+, what i need to wire to the Bosch O2 sensors ground wire?

Thanks!

 

[BTLSHP]

For the TLDR crowd. Is OX1+, what i need to wire to the Bosch O2 sensors ground wire?

Thanks!

Did you ever get the Bosch wiring worked out and would your recommend using the Bosch O2 sensor? I have one I need to replace ASAP. Thanks

 

[OffRoadScott]

Did you ever get the Bosch wiring worked out and would your recommend using the Bosch O2 sensor? I have one I need to replace ASAP. Thanks

I got the bosch o2 sensors that are plug and play and haven't had any issues with them, going on 2 years and passing emissions.

 

[BTLSHP]

I got the bosch o2 sensors that are plug and play and haven't had any issues with them, going on 2 years and passing emissions.

Are those the universal 15728's or something else with a plug already on?

Thanks so much for the quick response!

 

[OffRoadScott]

Are those the universal 15728's or something else with a plug already on?

Thanks so much for the quick response!

No, I ordered bosch part number 13081 and 13448

 

[BTLSHP]

No, I ordered bosch part number 13081 and 13448

Ok, those do not seem to be available anymore. I definitely have a bad one that needs replacement. Cruiserparts.net says they have the NTK’s

 

[OffRoadScott]

Ok, those do not seem to be available anymore. I definitely have a bad one that needs replacement. Cruiserparts.net says they have the NTK’s

If you have the FSM check the pins for the O2 sensor, resistance should be 5.5-6 ohms. Why replace only one, do both for piece of mind.

 

[BTLSHP]

If you have the FSM check the pins for the O2 sensor, resistance should be 5.5-6 ohms. Why replace only one, do both for piece of mind.

Yes, I will do that tomorrow or Monday. I just noticed that on my ToyOBDI device the thing has completely stopped registering voltage changes at all and is showing "Lean +20." Engine is running poorly for the first time ever.

But, you are correct in for a penny in for a pound I will end up doing both. This refresh has been expensive.