The check engine light on my 93 SC300 came up couple days ago. I finally had the chance to short the TE1 and E1, and it gave me code 28. I bought an OEM one from lexus dealer for $109.

I have done research on this website, but it's still not quite clear which side of the two main 02 sensors. Some people said its the rear side, and some people said it's the right side.

Which one is right? Can anyone explain clearly? Thanks.

Also, I'm planning on changing the spark plugs this weekend. I understand that I have to remove the throttle body. My question is, does anybody know how much torque should I set on the torque wrench when tightening the throttle body assembly?

 

Not sure about the torque specs. I'd check but the manuals are packed up. Just make them good and tight. For the 02 sensors I'd swap the rear one first and see if the code drops out and go from there.

 

Or you could just use the good sensor to feed both leads and save yourself $109. You just basically feed the single output to both ECU leads. (That's the way mine is running)

 

Why does the 2jzge have two o2 sensors in the first place? I had code 28 for a month and then it disappeared never to be seen again.

 

It is better to change out both. Some people have complained that changing out only one will, give you rough or odd idling. Besides, if one goes it is only time that the other will also go. The reason why there are two compared to one is. There is a separate bank of cylinders 4 on each side. There are also more than one computer governing these bank of cylinders. Converting it to one o2 sensor is a bad idea. You can get the OEM sensors here. They are reasonably cheap vs. dealer which, I paid like $380. The passenger side on the SC 400 is the hardest to replace. The driver's side is a snap. Torque specs are:44Nm(450kgf.cm,33ft.lbf) It is most likely you will not be able to fit a torque wrench in there. I just tightened as tight as possible. Check out the link. I found this place after I replaced my sensors which, I wish I would've found earlier. It is in Canada which, is cheaper vs. USA. Also, the o2 sensor is NTK which, is the exact same part as OEM not, Bosch.oxygen sensor

 

Yeah that's nice...
BTW
We're talking about an SC300.

I guarantee you that there is ONE ECU controlling 6 cylinders.
There is NO independent fuel metering within the cylinders, hence no real reason not to use ONE 02 sensor.

 

The REAR O2 sensor (the one at the cat. converter) exists merely to report on the efficiency of the cat, and plays NO role in managing the engine. The FRONT sensor is, of course, critical for engine fuel management.
The only function of the rear sensor is to cause the checklight when the cat. converter has worn out.. such checklight doesn't affect engine performance, but, of course, can mask other malfunction codes.

There is a company on the web which sells a generic O2 'simulator' which sends a healthy signal to the ECU, allowing you to completely eliminate the rear O2 sensor. If you're not an environmentalist, At $50 or so, a better solution than springing $300 for a new sensor.

I have one installed on my car, and it works flawlessly. You can contact me for specific wiring instructions to the ECU. The simulator can be seen at:

www.casperelectronics.com

 

I have the Check engine light on along with my TRAC light. Know that this points to an O2 sensor. But, I am getting a nasty smell coming out of my left exhaust (could have a bad CAT). Should I replace the CAT or do the O2 Sensor first. And I need a site that has the rear O2 sensors,globalautoparts only has the fronts. Also, I would like to know how to replace the front and back sensors myself. DOES ANYBODY HAVE A DIAGRAM OR A STEP=BY-STEP ON HOW TO DO THIS, I KNOW WHAT TOOL I NEED JUST WANT TO KNOW HOW TO MORE THAN ANYTHING.

you can post it here or PM me or email me at bladez42598@aol.com

thanks
vinnie