Hey Haha_jizzjizz ! Disconnect overnight, clear codes....Really good advice. So I went to disconnect, because I thought "It's acting so weird and throwing irrelevant codes and such", like you had noted....
Couldn't get into car. Key fob dead? Took voltmeter to key fob battery....3V. Should work. Used mechanical key to get in. No lights....at all. No power to anything...at all. Put portable, mini-Lithium ion jump starter on battery and waited a while....nothing. Couldn't even get the LED that lights when you open the door to light up (had to mechanically release the back hatch, from inside, to be able to work easier, since there's no way to open the back hatch from the outside without power).
So I put a charger (for AGM) on the 12V battery, and it's reading 2.7-3.0 V on the 12V battery. Holy crap.
This 12V battery came from the factory. 2013 vehicle. I like to make things last....that's why I'm so careful choosing fluids for trans, inverter, engine, filters, etc. I even Aerospace-303 my CV boots and the rubber hoses under the hood.
Needless to say, it might make sense to include changing the 12 V battery as part of the 100,000 mile "check-up", if it's the original 8-year old battery in there!!! Hahaha!!
I have a strong feeling that this may be a case of "Check the obvious stuff first". I recall hearing (probably on these forums) how the car can do all kinds of crazy stuff when the 12V battery gets really low/dies. It can act in all kinds of weird ways, I recall hearing. When I put that Li-ion jump starter on the battery yesterday (just to boost voltage) that's when the car started and ran...still throwing codes....many of which relate to voltages of sensors and such. Before that, it wouldn't even try to start. And most of the lights went away when it started after putting the charger on the 12V battery.
After obsessing about burning out my inverter-coolant pump, by getting air into it....and realizing my coolant pump was working....I figured I must have air trapped in the inverter. Still possible (and I even looked up images of the inside of the inverter and obsessed overnight about all those little channels in there that could get air bubbles trapped in them). Now I have a feeling that a new battery may just clear everything up! It's so friggin' crazy how the battery died RIGHT AFTER changing all my fluids...but I did run that inverter pump a lot while changing the fluid out....thus draining the battery a lot.
Well, I put a proper, plug-in charger/jump starter on the 12V and the lights at least came on (dim). Car wouldn't even try to start. Just gave me "check engine" light symbol, and nothing...yet.
Now my charger / reconditioner (set on AGM) is plugged into it, and I have a strong suspicion (and dire hope) that all will be good with a good 12V charge. Optima yellow-top battery is on the way.
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Funny aside: Three friends and I were working on getting a Rotax (4-cylinder) aircraft engine to start. I'm pretty knowledgeable about engines (compared to the average population), one guy is an electrical engineer, another guy a mechanical engineer, all four of us pilots who've worked on our own engines quite a bit, and the fourth guy who's worked on airplane piston engines for years, and helped to build several experimental airplanes, was baffled too.
When we weren't getting a spark, we pulled plugs and cranked it over while watching to see if there was a spark. Difficult to see in the bright sunlight, certainly, but it looked like one set of plugs had no spark (often aircraft have two plugs on each cylinder for redundancy). The other set seemed to have intermittent spark, but difficult to tell in the bright sunlight. We also couldn't see any fouling on the plugs and we were cranking the engine with good voltage. This engine had run several times (was almost brand new, and was running fine before this).
It was a full 90-minutes of screwing around, with all kinds of theories being bantered about, before....yes, you guessed it....we realized we were out of gas. Laughed our asses off at ourselves. With gas, the thing ran beautifully. Whaddya-know, they don't run without gas.
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We'll see, but it'll be great if I'm just an idiot again. I called Lexus to see if I still had free road-side assistance (did not), talked to the head of maintenance at the nearest Toyota dealership twice about all this, planned on likely towing it down (1.5 hours) on a friend's trailer and leaving it for two weeks (soonest he could get to it). Tried snaking tubing through the coolant reservoir into the coolant pump (no luck), tried squeezing the hell out of the inverter coolant system hoses (no air bubbles), checked all the fuses I could (and even volt-metered the Ohm resistance on those relays...don't know what's normal but all the relays read about the same resistance, so it didn't seem like a bad relay). Disconnected the ECU and reconnected. Borrowed OBD-2 reader after researching Scan Gage 2 (one of those is on the way...which is good, long-term, anyway). Got under the car (on jack stands) and planned out how I was going to replace this pump. Researched pump prices and wondered how to get the air out of the system once I replaced the pump. Agonized over "frying" my inverter due to coolant bubbles trapped in the inverter. Researched inverter prices. Spent a few hours on here, with OBD-2 codes that don't a lot of sense. Reviewed images of inside of inverter...and noted all those little channels...convinced overnight that I must have air bubbles trapped in those channels inside the inverter. Toyota service manager hadn't heard of that, when I called today...but admitted he wasn't all that "expert" on inverters. He didn't know of a system that would purge the air bubbles out of the inverter. Yeah, pretty convinced last night and all morning that I had air bubbles in my inverter.
Sure, I could have a bad inverter. Could still be something else. But there's a really good chance that it's all wacky stuff ENTIRELY related to a dead 12V battery. Man, that would be great. I could laugh my ass off at myself, once again, and if the car runs fine after this, it's going to be just a good story....One that I'll likely not tell many people.
So my advice to you guys: Change your 12V battery before 8 years have passed, from date of manufacture, or 100,000 miles....whichever comes first.
I'll post up when I know something!! And thanks again Haha_jizzjizz. Your advice and noting that the codes didn't seem to make sense, and also suggesting disconnecting the 12V battery overnight is what prompted me to go down to the garage and disconnect the 12V battery....when I could no longer get into the car! Your suspicion of an electrical system quirk is hopefully spot on!!