The Mysterious Prius Warning Light Syndrome (and other adventures)

Hey all
Having a few issues with my Gen 2 now in her 171,000+ km, or whatever that is in miles 100k+.
On a 50km trip the red triangle showed up with the brake icon (!) being somewhat cautious I took it home. The front pads have never needed changing so I thought I would just replace them. Aux battery was disconnected in this process. All went well except in the process of the same trip some days later the warning lights showed up again in almost the same stretch of road.

This time returning in the dark the ABS warning appeared, the head lights went dim, cruise turned off, the AC turned ineffective. While processing what was happening the car shut down, no power and the throttle went dead, lost power steering, lost power brakes, manhandled it off the road. Turned the car off. turned on again and just the red triangle, engine inspection amber and brake warning.

Drove off and all was well for 10k, then we went through the above again. After reset this time 10 yards. Reset and on till I got home. Every time a shutdown occurred the ABS lamp had come on, every time I got it off the road (country roads very little traffic at night mostly just kangaroo) and reset it, despite the warning it seemed ok. Full power produces a strange surging though, like power on power half, cycling at around five seconds.

.. it was you know, an interesting evening if somewhat concerning ..

Now Im guessing many are thinking what about the aux battery, which is circa 3-4 yrs old. I ran the service menus and found the battery was low at around 12v, it went lower under load with lights, 11.8v. Battery has been read other times over the past few days at 12.2v and 11.5v. Everything else I can see seems fine as far as fluids etc, its been darn hot here so the AC has been getting a pasting.

So to my question, is this weirdness typical of a failing 12v? Or is there more I should look into?
I extracted some codes I cant make sense of, non of them appear like the Pxxxx codes for all those worrisome ills we all dread. They dont google well so Im going to pull a rear wheel off tomorrow and see what the rear pads look like.

Any other scarey stuff people can think of might be appreciated, Im just hoping its the aux battery.

 

"Not sure why you keep going after the brake pads you have a master caution alarm the RTOD and worn pads will not cause that alarm."

Mostly because I get the brake warning lamp (!) and ABS after which ultimately it fails
During the doing the pads I disconnected the 12v and more recently, Ive found if I disconnect the 12v the warning lamps go away for a bit, but then obviously return, but not instantly. The sequence is, RTOD and the (!), then the master alarm on the right (might be different in the US because we are RHD, then its set up to give the ABS warning, which has reset itself on about 3 occasions, also killing he master alarm.

So they all seem brake related, but ok perhaps that doesnt mean much

Ive never had to jump start the car

 

hmm so not great news, maybe not as bad as it could be
there is not much access to services here, so it might depend a lot on what I can do myself
thanks

 

there is zero chance of that out here

https://flic.kr/p/oGjUwv

 

so here are very similar symptoms, note icons
of course the 12v is easy to have checked, so I think I will have that looked at and go from there
thanks for the help

 

I learned how to look at them from youtube videos, at first these were with the car off, and with no load. Perhaps surprisingly that was one of the lowest voltages. Then I learned you can turn on lights etc and load the battery, and I could see voltage drop substantially and quickly. The worst reading at 11.5v is not perhaps as bad as it could be, but it is a battery that is beyond flat.

Ok so when you are looking at the voltage you can start the car, and I did this twice. Im not sure what goes on there but it seems to me the 12v battery hands off to the main battery, and the reading becomes a solid 13.4v. By that I mean it seems you can do add load like I did with lights but the voltage never deviates. Which in a sense is disconcerting because it doesnt explain the on road shutdowns which I have had at least 6.

 

Absolutely right, I was going to spend a part of today acquiring Torque for my smart phone and then figuring out what I need to connect it. Its like a furnace out here today (113F) and I need to plan my day so that I can get the battery checked with some regard for my safety because if the car dies in the middle of nowhere I could find myself in some difficulty. You cant just hail a cab or leave your car out here and just walk home unless you are really close because its the best way for people to find you. I hope that makes sense.

Hence the Torque thing will be investigated overnight but will take some time to organise and effect. I have access to an old laptop, I think at the moment it has Linux on it, but that can be changed if needs be. Thing is although I can get stuff flown in it might be as quick to remove and strip the HV battery and go through the voltages one cell at a time. And that it seems tells me what I need to know, perhaps not everything I need to know but enough to make some decisions.

 

12v Battery tested and its putting out 12.8v static, 330 CCA when this size battery produce 390 new

ok so I get the battery tested and his tester says that the voltage is 12.8, the CCA is 330 on a battery that when new produced 390. He also got a check light that said it has a bad cell, which he says is weird because his meter will just say BAD CELL in the display if it has one and hes never seen that light up without the display. He said in normal course he thought the battery would be ok, but he admitted he had no experience with a Prius and he just didnt know.

So I went through a few things with the display again and recorded images of the codes I found, and recorded the voltages the battery was putting out via Prius display. This amounted to 11.7v, then 11.2 with a bunch of stuff turned on, on accessory 10.9v with everything I could find on, and back to 13.9v engine on with everything on.

sorry images got shifted around a little loading them
dont know what to look for with inverter cooling system flow,
but I know where the coolant bottle for it is.

.

 

I have added Torque to my fone but the dongle wont arrive till early February
So I guess I shall see what the strip down of the HV battery brings over the weekend
If the bus bars dont look too corroded and/or are easy to spruce and the voltages check out, I shall be replacing the 12v
if not one way or t'other I know where I am ...

it was 47C give or take yesterday which is 116.6F

 

This is the cover to the bottle that says 'Do Not Open While Hot' right?
Turned it on and no, took it for a 10km drive and still no
The surface shimmys a bit when the engines on, probably vibration, I dont see it moving.

I think the pump is a remote part in the engine bay,
looking from the front of the car its on the right in the engine bay below a black box for relays
is that right?
theres no vibration or movement from it
im looking for fuses ATM

 

Yes I think thats it, also corroborating that it happened after about 15 mins journey, then repeatedly, but short journeys were fine
Checked the circuitry this evening, fuse and relay are good, theres power to the pump but no pumping happening.
Sourcing a replacement pump

thank you for the lead on the pump, Id never have guessed
and thank you all for your contributions and analysis, every little bit counts
keep doing what you are doing

these are damn interesting cars