HV battery or something else? U0100, P3000, C1259, C1310, B1412

i wonder if they'll find a lot of corrosion

 

What's your 12 volt showing standing there resting get it load tested just to make sure it's not going bonkers when you're going down the road causing all the communication problems

 

You need to test the fuses for continuity with an ohmmeter. Visual inspection is not a very reliable method.

PS:

Hybrid Control ECU says it has 5 DTCs and you only gave 2;
battery ECU says it has 3 DTCs but you only gave 1.

 

If you are really in a jam for transportation that may work.

The downside is that the reset could clear some information that would lead someone to a proper diagnosis of the problem.

It may take time for the onboard diagnostics to get back to where they are now, and there is an outside chance that a problem condition could get worse (more expensive) during that time when the computers are re-doing their diagnostics.

 

You wouldn't. But you could use a "memory saver" cable to preserve the ECU's memory while the 12v battery was temporarily absent.

EDIT: Just to add, I don't see much percentage in the 12v deal.

When I first got a Prius and came to Priuschat, I was wary about electronics not booting properly in low voltage conditions, because I'd seen things like that in other cars. It seemed pretty reasonable to expect the same from a Prius.

I don't really worry about that any longer, because I've read many accounts and seen firsthand that Prius ECUs are very good at booting up and operating normally even with weak 12v batteries and undervolt conditions.

A dead 12v battery is another story of course.

 

Yeah we'd all like to have a 12 volt battery that actually shows 12 volts after we've been sitting a while Just one of those things although in reality when these systems are designed there is a percentage of leeway something like 10% whatever that is so around 10 and a half volts is like where you don't want to go below generally speaking and expect reliability maybe so I always trying to keep my 12 volt at 12 volts that's not really that difficult the batteries do pretty well actually every so often on a weekend or an evening I have a little tail back there that sticks up to the plastic piece I just plug that to my maintainer every so often not maybe once a month maybe every 2 months just to top off the battery usually it takes about an hour at the most

 

11.8 should get it The only problem is is if you have nothing behind that 11.8 a lot of times the battery can show say 12 volts and the minute you click the switch everything goes dark and you check the battery again and it's like zero turn it off let it sit 20 minutes it'll show 12 volts again but there's no AH behind it nothing to back up what it's old worn out plates are trying to show you or something along those lines I've got batteries sitting out here that show 12 volts and if I hook up a light bulb or something to them it'll flicker for a minute and then go dead because that's just the surface charging that keeps coming back rarely is it 12 volts but it can be close but you're getting gauges and lights and also I would assume you have 11.8 volts with something behind it as it's holding the lights in the car and an ACC position I would imagine if you put it there

 

That's a good test procedure.

Your result isn't perfect, but it's good enough to rule out bad 12v for now.

 

Do I assume correctly that when you scanned all systems with your Autel, that the ECM did not respond?

Having the ECM "offline" could account for most/all of your concerns and codes.

Something could have failed (like the downstream S2 oxygen sensor) and popped the 7.5A IGN fuse underdash. That would prevent ECM turning on = no running & comm problems.

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So at this point does the car run? From you initial post it sounded like the car was "dead in the water".

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