Which O2 Sensor is #1? (1 Viewer)

[Hltoppr]

1992 FJ80, Stock 3FE.

Code 21 on the 'ol check engine light....indicates the number 1 oxygen sensor is having issues. ( A code 28 indicates the #2 O2 sensor)

Problem is....the FSM doesn't designate which O2 sensor is #1!???

So, anyone know which one is #1 and which is #2?

-H-

 

[robbie]

The exhaust that services the 1st 3 cylinders is the #1 sensor. I typically change out both at the same time. They usually fail within a short time of each other. later robbie

 

[Arya Ebrahimi]

The first one

Sorry, couldn't resist.

 

[Hltoppr]

Thanks Robbie!

I changed out both sensors at 177,000 miles with OEM ones from Dan; however, I think I may have had one go bad, as the resistance on the heater is out of spec.....

Just want to make sure I've got the correct one.

-H-

 

[Safado]

I posted this awhile back and didn't get an answer....actually looking for #2.

Now I know, thanks Robbie.