I do a little towing with my 2013 GX460 so I decided to purchase an OBD system to monitor transmission fluid temperatures. I'm happy with the OBD system (Veepeak Mini OBD reader, OBD Fusion app for iPhone) and the install went smoothly. On my first drive (not towing, just an easy highway drive) I noticed that the OBD Fusion app was telling me that one of the two O2 sensors was reading 0.00 the entire trip. The second O2 sensor was generating data but 02 sensor 1 stayed at zero all the way there and all the way home. I have no problem codes flashing up on my dashboard.

Anybody have any experience using OBD Fusion with a GX460? How many 02 sensors are there on a GX460? Thanks for any advice.

Try reading the second sensor on the first bank instead of the first sensor on the second bank. Unless there is no second o2 sensor? I could be way off.

Thanks for the response. I spoke to my Lexus service rep a few minutes ago and he said that the GX460 has four sensors--two air flow sensors before the catalytic converter and two oxygen sensors after the cat. He said that if an O2 sensor was not functioning the check engine light would absolutely be on. Mine isn't. He also said that he hasn't ever seen a GX460 have an O2 sensor that needed replacing. I'm thinking it is just a compatibility issue with the OBD Fusion app. I'll try to play with that. Other than that problem, the OBD Fusion app is pretty cool.

I am looking to replace the driver side Air Fuel Ratio (AFR) sensor, also known as upstream O2 sensor, on my 2015 GX. Doing the passenger side was not easy, but at least it was possible. Driver side sensor is blocked by an additional exhaust pipe and seems impossible to replace with engine in the vehicle. Has anyone done it or have the instructions from repair manual?

Curious, do you have a failure or something? Unless I missed something here on this forum this is new to me.

There is no failure. There are just certain items that I like to replace every 100K miles instead of waiting until it fails. I have my own OCD-based maintenance schedule that I like to adhere to with my vehicles and replacing upstream O2 sensors is one of the items on that list.

Gotcha, but I will say I have not heard about any failures here so not sure if I would be concerned with it. Others might chime in with different results.

i’m at 160K miles with basic maintenance on my 460 base model and it has has been trouble free since bought at around 45K miles.

I get the OCD thing with other manufacturers but you have a Lexus GX460 :-)

Thanks for your input, tecman, but I have my reasons. I switched to Lexus after having recently owned older, higher mileage BMWs ('03 M3, '02 M5, '06 Z4, et. al.) and I can't say that I'm blown away by how my 2015 GX has held up over the 3 years I've had it so far. At 68K, the dealership already had to address the timing chain cover leak as part of CPO inspection and the original Lexus battery was already toast (after 3 years). By 100K, the input shaft seal on the transfer case started leaking (visible drops) and I spent 4 hours replacing that. A couple of weeks ago, the second genuine Lexus battery crapped out after almost 3 years of use, so I upgraded to an Interstate 27F from Costco for $102. Now, at 105K, my radiator is leaking by the upper hose and leaving puddles of coolant everywhere I go, so that also needs to be replaced. My wife's '06 LS 430, on the other hand, that's built like a tank and is bone dry at 170K miles. Even my M5's radiator didn't explode until 119K miles and the Duralast Gold battery it had when I got it lasted the whole 7 years I owned it.

I know you didn't ask about downstream sensors but included them here as well for other's reference if they come across this thread in future. FSM does indicate major task of exhaust manifold removal for AFR.















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Exhaust Manifold removal

Thanks, Acrad!

please report back with any tip/tricks used when doing the driver side along with any used when you did the passenger side.

gg

Hey all,
Bit of a long story but this is kicking my tail and I am in need of some help.

Little bit of a backstory that I feel may need to be said.
I had to do the "coolant valley plate leak" here several weeks ago. Job was a pain but it all turned out fine.

2 weeks later i had the P2238 code pop up-"bank 1 sensor 1 current low"
-went away then came back.
Finally I went ahead and swapped out the O2 sensor on bank1 sensor1.

7 days later the code is back, and I am not sure what else I need to look at.

Can anyone give me some advice on what to troubleshoot next??

Thanks for the help, as I am at my witts end.

Not sure if any of this helps?

The wiring diagram does help, I appreciate it @Acrad. This has become a serious headache..New sensor-same problem. Going to run down some electrical stuff this morning and see what i come up with. Thanks!

I always thought O2 sensors should be replaced in pairs especially if you are over 100k miles.