About a week or so ago my check engine light come on in the 1995 Lexus ES300 and when it was scanned, the bank 1 sensor 1 O2 sensor came back as bad. I decided to look up the part on Amazon and came up with this for a low $70:
The Bank 1 Sensor 1 O2 Sensor on this model Lexus is the one behind the engine, nearly against the firewall. It's not the front-most one and it's not the one past the catalytic converter under the vehicle on the exhaust. It's the toughest one to get to compared to those.
Knowing this, I thought about taking the car to someone and having them put it on but decided to do the work myself and learn something while saving a buckazoid or two.
The sensor came in today from Amazon and I went to my local parts shop and they happened to have O2 sensor sockets on sale for about $8 - not a bad start! I also bought a can of Blaster to help loosen the old sensor:
Here's the type of tool I bought to remove the sensor which worked great as it's flat and fits very, very easily into tight spaces:
With these items in hand and the Lexus in the garage nice and cooled off, I got to work. Here's some pics.
Here's the tools and new sensor
The new O2 sensor came with some Locktite type compound (I hope that's what it was!)
Closeup of the tool used to remove the old sensor and tighten the new one
Ok.. Where is that B1S1 sensor? Let's start on the drivers side of the engine. Notice I placed my light there so it shines down on it while allowing me access on this side of the engine bay.
Creeping back behind the engine a bit now..
Look right behind the engine and in front of the firewall and thar she be. I've sprayed the Blaster stuff on it so it's shiny.
Up close and zoomed in.
Old one out, compared to the new one. I must say.. This was actually quite easy to remove. I simply slid the tool/socket over the old O2 sensor, attached a ratchet to it and with one tug, it broke loose. I then pulled the tool/ratchet out, unplugged the harness cable (just press the ribbed clip and pull apart), and then hand-loosened the old sensor the rest of the way until it was out. When I got it out I did a small "YEAAHHHH!!" celebration while shaking it and staring at it with crazy eyes and then went back to work.
Dirty as heck. I bet this is the original sensor from 1995.
I put the locktite paste on the new sensor threads, carefully, slowly lowered the new sensor through the cavity there behind the engine and into the hole it belonged and then hand tightened it into place. Reattached the cable harness and then used the tool/ratchet to make sure it was all tight and was done.
Overall, despite it being in a fairly rough place to get to, it was a very easy replacement. Couldn't have gone smoother and I think it took me 20 minutes tops to handle it all. It took me longer to make this post.
That went so easily, I'm wanting to change out the front O2 sensor just for the fun of it. Thanks for reading and I hope this helps someone in some way.