Going to post my experience here since I still don't have enough posts to be able to start a new thread. How many are required, btw?
My 2008 Sport v8 138k suddenly, and I do mean suddenly, decided not to start a week ago. Went out one morning, go to start it, and all I hear is a click and some gentle quiet whirring noise. Not one single turn of the engine. It has always started fast and immediately.
I live in a very remote area with no cheap way to get it to a mechanic, let alone a good one. A tow to a good mechanic would be about $600. When I found out the starter location on this thing, and how the later model v8's are even a lot worse than the earlier v8's, I damn near cried. No way to even tap the starter with a hammer.
I realize that there's a poster above remarking how replacing the starter is no big deal to fix, but he seems entirely alone on the internet in thinking that. Maybe he's simply an awesome mechanic. He's only done it twice, so I assume maybe his experience is on the older v8's without all the stuff still in the way even after you remove the manifold.
I spent many hours since then trying to diagnose the problem, both in Google and in the vehicle. Jumping off another vehicle didn't work. Battery in good condition. Cleaned the terminals although they were in good condition anyway. Starter relay was fine but replaced it anyway. All fuses fine. No OBD codes. All wiring looked good. Neutral Safety Switch fine. Chip keys fine. Security system fine. Since it's an automatic, no way to push start or just jiggle the starter. Since starter is buried, no way to tap it with hammer or prod it with a screwdriver.
Finally I ran across a video of a guy removing a starter relay and shorting the relay socket with a wire, just to be able to test whether a starter would actually turn under power, on vehicles where you can't easily get to the starter and test it properly. Hrm. Of course to do this you need a wiring diagram of the relay, which is printed on the side of most relays I think, but of course, not on this particular Toyota starter relay. Or maybe a smart guy with a multimeter could figure it out, but not me.
After much Googling I found a picture of an off-brand replacement relay that had the diagram on the side. I figured out that the socket pits that I needed to short were the ones that corresponded to the two copper pins of the Toyota-branded (Denso) relay (vs the two aluminum pins).
So I cut up an extension cord to make a wire to short with. If I had the sockets wrong, I could have fried a lot of expensive electronics. I held my breath, and did the deed. It sparked and seemed to make a louder click than it had been doing. But no engine turn. Sigh, oh well.
To make sure that I hadn't just fried something, I decided to put the key in the ignition, and make sure all the lights looked the same when I tried to start it. They did. I bumped the key and it started immediately, which surprised the hell out of me.
I guess the shorting wire provided a harder kick to the starter. I now suspect the starter contacts is what's wrong with my vehicle. I also suspect that if I had tried to short it again with the wire, the engine may have turned after that first kick to it. I will now be keeping that shorting wire, and my pair of relay pullers, in the vehicle. I'd suggest that anyone following my lead (it's not my fault if you fry your electronics!) to buy an actual set of relay pullers, as the metal sockets of the relays are too close to the lip, and it's easy to short that if you try to pry the relay out with a screwdriver. It hasn't failed to start since, but I don't trust it any more. That starter/solenoid/whatever needs to be replaced.
I was without this vehicle for a whole week while I tried to fix it. It has snowed here every day, and the vehicle was stuck outside on a slope. I may have to get rid of this vehicle, a vehicle I otherwise love. This mode of failure is not acceptable in genuinely rural areas. Having this happen is not why I own a Toyota 4runner. Maybe I'll get one of the v6 ones. I think putting the starter in such an inaccessible place, where you can't even really diagnose the problem without taking the engine apart, is completely not acceptable.