KahnBB6

iTrader: (5)

I need to pass smog by December and I have bought a #3 O2 sensor and OEM front cat for replacement.

For now I just want to install the #3 O2 sensor myself. I have a California 1993 SC300 which makes it an uncommon procedure. I have found the sensor on the rear cat and I know the connector wire goes under the carpet somewhere behind the seats. It's a PITA to get to that connector.

Do I just unbolt my driver's seat, remove it and the inner (interior plastic) side molding and pry up the carpet to get to the connector? Is there a best way to do this to avoid inadvertently damaging interior parts or the carpet?

Would the procedure for MKIV Supras be exactly the same only with an obvious difference in the interior bits?

I found this thread for GS300 #3 O2 sensors which shows a similar procedure: https://www.clublexus.com/forums/per...placement.html

Also, this thread covering the same thing for a 1998 Camry 5S-FE: http://www.toyotanation.com/forum/sh...d.php?t=197633

Does that pretty much cover everything applicable to SC300's?

ISFFUN

iTrader: (4)

You can do it without removing the seat through the center console, but you have to take out the radio and unclip all the wiring. it's a pain,

KahnBB6

iTrader: (5)

^^ Yikes. I'd rather take out the driver's seat. It's less time consuming. Do you happen to know where the actual connector is anchored under the carpet?

KahnBB6

iTrader: (5)

Okay, I found out how to do it:

Driver's seat has to come out. Then the console bezel and stereo/climate unit (just disconnect the two large blue and white connectors in the back and the ground connection). Then you can carefully peel the carpet from the console side. The grommet is close to the parking brake on the driveshaft tunnel. The connector is located in a crevice only accessible by removing the stereo and climate control cluster.

Here are some pictures for anyone who needs to do this:

2jznosht

Do all sc300's have the third o2 sensor? Or is it just a cali car thing?

KahnBB6

iTrader: (5)

To my knowledge, on OBD1 SC300's it was only for California market cars, however I have heard that Supras had #3 O2 sensors since 1993.5. Since they reportedly shared the same assembly line its interesting.

I think all OBD2 SC300's had three O2 sensors.

If you have a non-Cali car the easiest way to check is to look under your car at the #2 cat and see if you have one there. The miniature upturned heat shield is a giveaway.

ISFFUN

iTrader: (4)

I'm actually replacing mine this weekend and decided to go with the Denso 4 wire splice type instead of the whole harness..just a lot less work in terms of unbolting stuff and moving wires around inside.

Pesky check engine light!

KahnBB6

iTrader: (5)

Heh, I hear you. I am not sure of the part number for the wire-it-yourself version but check the flange size against this: Denso P/N: 234-4214.

Oxygensensors.com listed another Denso (with the full connector) for my '93 which not only was the wrong connector but also the wrong flange size. I am exchanging mine for the part number listed above. There should be pictures listed before you get ready to purchase. They should have corrected their error by now in their system.