Changing Bank 1&2 UpstreamO2 Sensor (1 Viewer)

[Chilly4545]

So I’m changing (or trying to) my DS upstream sensor. 2005 Gx.
Check out this photo. The sensor is 160 degrees hidden in the back side of the exhaust pipe.

Take a look at the picture.
How did you guys access the sensor to take it out??

 

[Chilly4545]

Also - how critical is it if I only want to replace bank 1 without the coresponding bank2 sensor? Can I get away with it and save $305 bucks?

 

[CarolinaGX]

I used a tool similar to this and positioned the "ear" where the ratchet extension goes to the side of the pipe. Then placed an extension into the tool from the bottom. Once it moved a few degrees I was able to remove it by hand.

What code are you getting?

 

[greenscobie86]

I went through the D/S fenderwell with a similar tool @CarolinaGX posted above and a flex head ratchet. Took about 10 minutes to change. Piece of cake.

FYI: My code was P0031 which is a (heater circuit control low) code for B1S1. The Denso OEM sensor was about $45 at RockAuto.

IMO, if you only have one code, replace the offending sensor...

 

[Chilly4545]

Got it!!!! ds bank 1 complete.
Now on to Bank 2

 

[Chilly4545]

Ok got both sides done.
lessons learned:
1. Absolutely a requirement to use the tool pictured
2. Long fingers, skinny arms, a flat head screw driver and rubber forearms needed to unplug and re-plug the harness

I still have the code after 25km. Hope it goes away or I’m going to do that downstream sensors.

thanks for the tips CarolinaGX!!

Colin

 

[ArBrnSnpr]

I did all 4 sensors a few months back.

I'm still pissed at Lexus for their sensor placement!

 

[Chilly4545]

I did all 4 sensors a few months back.

I'm still pissed at Lexus for their sensor placement!

I’m wondering if the reason my code didn’t go away is that I still have the downstream sensors to replace??

 

[CarolinaGX]

If you have a scan tool, clear it yourself and see if it comes back. Also, check to be sure that you don't have an exhaust leak. In my case, I had a leak that the flange for the second cat after getting high centered in TN. I fought it for months and ultimately used 2 gaskets to seal it.

 

[Chilly4545]

Borrowed a friends scan code - cleared the code and it hasn’t come back in 50km.

thumbs up

 

[white_lx]

Had to replace the B1S1 on an '08 GX470. I used the same setup with a universal joint on the sensor socket and a long extension to save my knuckles (picture).

One other tip regarding the connector release: first pull on the sensor part of the connector with long needle nose pliers. Then push on the tab on top to release it with a small bent pry bar or screwdriver. It will click and stay unlatched because of the preload by pulling on it first. Then you can just pull it out. It is much easier than trying to pull on it while pushing on the tab at the same time. Or maybe my hands are just too large.

I had a P0171 (lean bank 1) code. No P0174 (bank 2). It turned out it was the B1S1 A/F sensor. It looked like it was working fine showing around 3.3V, but using the +12% and -12% fuel trim testing in Techstream, I found it was not responding as much to lean and rich conditions as the B2S1 sensor. The B1S2 sensor data was also helpful in confirming that it wasn't really a lean condition. No other codes.

 

[trd4x4]

P0031 code came up last night. Cleared and popped again this morning. Upstream drivers side? Have a denso sensor in my rock auto cart. Doesn’t specify driver or passenger side. Just “upstream”. Assuming this is the correct part. Denso 2344138.

 

[MoonBoon]

P0031 code came up last night. Cleared and popped again this morning. Upstream drivers side? Have a denso sensor in my rock auto cart. Doesn’t specify driver or passenger side. Just “upstream”. Assuming this is the correct part. Denso 2344138.

P0031 should be the driver side - Bank 1 sensor 1. I have the same code too and just received the Denso replacement sensor today.