Brake, ABS & traction lights, AND a Surprise Bonus!

I think the break actuator in the car houses all the computers for the breaking so if any of that would be messing up I would think it might shut off your cruise control just seems like it would follow some logic like that

 

He's probably right that 3 sensors failing at once wasn't the reason the detection conditions for those codes were met. It might more likely be an issue in some segment of wiring common to them, or less commonly a problem with the ECU. But why should we be guessing? Is he against going through the troubleshooting procedures, the ones in the repair manual if he doesn't have better ideas, to find out what did cause those conditions to be met?

Same idea for the battery. It might be just a year old and all shiny and nice, but if that 12v fault (what was it? C1241? always better to say what codes you had, not just paraphrase them) has a freeze frame, the freeze frame will show you what the voltages were when the code was set. They might surprise you. But also, they're measured at the brake electronics. A low voltage there doesn't necessarily mean it was low at the battery. Again, that's what the troubleshooting procedure is to help figure out.

 

A chip in the inverter right. This part goes bad and gets replaced in Gen 3 converters I thought which has no bearing on what's going on here. I'm sure there's a similar chip in the Gen too I don't think we hear about it much because the Gen 2 inverters are pretty dang solid I have several here waiting to go in cars when their originals fail which looks like it may be never.

 

It might not have been Mark Twain who said it, but "the things you know that just ain't so" still sums up something to watch out for. Sufficiently low voltage can indeed be the cause of some trouble codes—especially the ones that mean "hey, letting you know the voltage is low over here"—but also gets blamed for a much wider variety of things because it's an easier story to reach for than doing the legwork to find out what's really causing the things.

The electronics industry has gotten really, really good at voltage regulation. The "absence of a conventional voltage regulator" just means we're no longer stuck with the old metal arm in a magnetic field that vibrates between giving your alternator too much field current, too little, or somewhere in the middle when it's between the contacts.

The Prius regulates your voltage pretty much the same way every modern electronic device does: pretty accurately, by measuring it, comparing it to the target, and pulse-modulating the DC/DC converter accordingly.

It also chooses the target voltage according to conditions. It can set the target up around 14.8 if it thinks your 12 V battery is low and could use a bit more charging. It tends to lower the target closer to 13.5 if you're driving down the road and it doesn't think extra charging is needed. It also takes occasional brief samples where it sets the target below the expected battery voltage and evaluates what the battery's putting out. These are more brief than you'd notice, but they show up if you're datalogging the voltage.

So the voltage is normally pretty well between 11 and 15, which is about what you could count on from the old-school vibrating reeds anyway, and is pretty much the range that any "12 volt" equipment is built to gracefully handle.

And then within the car's ECUs and similar digital electronics, a local regulator will take the incoming 11-to-15 and produce a rock-solid 5 for the microprocessor circuits, just as in any other 21st century electronic device.

If you look up the detection conditions for trouble codes, you'll see that the ones triggered by the incoming nominal-12-volts are generally not triggered until it drops below 9.5 or so. The ones that are triggered by the locally-regulated voltages inside an ECU have much tighter tolerances, being set for any deviation a quarter volt above or below 5.

And that's all interesting stuff that it doesn't hurt to know, but the quickest answers to what's up in your car might still be found by systematically working through the troubleshooting procedures. It's not like those were written by people who don't know how the car works.