I wouldn't mind it depending on the savings. The more I think about it the more I'm thinking at this mileage the other sensor is probably near end of life as are the motor mounts (also require removing engine / transmission). Then there's the rear 2 spark plugs. 4k is a lot for an oxygen sensor , but if If an Indy shop that could do both sensors, motor mounts , plugs etc for ~$3000 it might be worth it. 🤔

 

I don't see why you can't just use the LS 460 starter tutorial to remove the exhaust manifold with the cat attached and change out the O2 sensor.

You might have to fight to unplug the connector like Astro in the video but it seems doable unless the AWD system somehow prevents you from removing the exhaust. Skip to 12:37 in the video.
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Those pics are hard to look at. I can’t believe Toyota designed it that way. Unfortunate.

To the bold. Thought about that earlier, I was told it’s not the best idea to remove the manifold as you open a can worms. My V8 exhausts manifolds are one piece with the cats. I was not thrilled to discover that. I believe the manifold will be very hard to get at in this vehicle anyway.

 

I haven't read through this entire thread forgive me if this was mentioned. If the sensor on bank 1 has easier access would it be possible to use it's signal to feed the problem bank 2 sensor wires? If access is difficult with a wiring schematic you should be able to trace down the wires. I'm not sure what the long term effects would be. I can't imagine there is a huge difference between both banks.

 

Good news my mechanic was able to access the sensor without removing the engine and transmission. From what he explained he detached the exhaust after the cats and snaked up past the cats. He has a good amount of scrapes on his forearm and elbow but was able to get it. He noted that removing the exhaust manifold wasn't and option and that the driver side would have been far more work.
Charged 3 hrs of labor which is way better than the 20. Crisis averted, I'll create a new post when I'm blown away by the cost of some other repair.
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I'm glad it worked out. Sometimes it takes a while to figure these things out and you have to be committed to finding the least expensive way. Did he say why he could not remove the manifold?

 

Between the already tight design ,the awd and hybrid parts it's too tight to remove the manifolds.

 

Makes sense, I would think the hardest part for your mechanic was unhooking the electrical connector.

 

Awesome! Glad to hear

 

Lots and lots of unhelpful information in this thread.

The factory service information says 20.0 hours of labor to replace the upstream O2s. Engine and trans are supposed to come out. Thats unreasonable to anybody who is not a Ferrari owner, and a legitimate concern for most of us.

Im going to attempt it next week, either pulling the manifold or the exhaust. Usually thats not an option on a Michigan car.


Edit - went out to take a look. Left side, b1s1 was accessible from the top. didn't even take the engine cover off. Took about 15 minutes, mostly getting the tools out.

 

lots of unhelpful info here too. Your a year late and didn't even provide info on how you got it out from the top.

Of course you obviously removed the covers and most likely the battery and tray but you didn't state that so everyone is left guessing.

 

Missed the developments in this thread...

Re: the 600h starter and hybrid system and inverter and whatever:

The only things that seem to fail are:
1) hybrid battery - expensive due to it being unique for the ls600h - it's the only car with the 12-cell modules.
2) engine flywheel.
I don't think I've read of a single inverter failure on these vehicles in particular, and I've had a reason to research a lot. Same for the rx450h (NOT the 400h), the 4th gen gs450h, some other newer models. Might have something to do with the power transistor packaging and cooling.
The starter and alternator as separate items are not necessary. The transmission itself is pretty much bulletproof, other than the bearings for the auxiliary oil pump - same as the gs450h.

As for the car itself - others have said it before, it's at the opposite spectrum of a corolla. Cheap to buy doesn't mean cheap to run and maintain.

 

A year late for the OP, but not for the people like myself that use the search function to find answers to common questions.

I used a O2 socket, a universal joint adapter and a 12 inch extension with a nice long ratchet. It moved, but was stiff, so a squirt of PB.

Plug was easy to get to, but had to be released one handed..

I did not remove a single cover, or the battery, which is in the trunk on a 600.

 

A year late for the OP, but not for the people like myself that use the search function to find answers to common questions.

I used a O2 socket, a universal joint adapter and a long extension with a nice long ratchet. It moved, but was stiff, so a squirt of PB.


Plug was easy to get to, but had to be released one handed..

I did not remove a single cover, or the battery, which is in the trunk on a 600.

The O2 is straight down in the hole in the left rear of the engine. The O2 in the pic was a cheap sensor I had that fit, but didn't work. It needs the right a/f sensor ill get tomorrow.

 

NICE!!! good to know it can be done from the top also. Thanks for posting your findings