Check Engine Light and Triangle; Car is acting weird

I believe you have an abs brake actuator pump failure, that's covered under warranty.

A failing battery will not result in you losing brake function

 

did they tow it on a flat bed? if so, how did they get it on?

 

As per JC above, it sounds a little like this:
Brake Actuator Assem - Warranty Enhancement | PriusChat

 

JC is right. You have a bad brake actuator pump. There have been enough failures on those that Toyota extended the warranty to 150,000 miles. Good thing, too because it costs almost as much as the battery! It's also possible that the 12 volt battery is also on its last leg. That will give all kinds of weird lights and codes.

I have not heard of needing to access the rear of the car to program a key fob.

 

That's the key question. The red triangle means any one of a hundred or so different things, some of them serious, some of them quite trivial. They are identified by different five-character "trouble codes". It is an exercise in futility (or attempted psychic performance) to try to say what it means without retrieving those codes from the car.

It sounds as if trust has broken down between you and this dealer, so you might not be confident they are giving you the exact set of codes being read from the car. Maybe if they let you watch as they connect Techstream to the car and read the codes, it would help. Or another dealer, if there is one near you.

Other businesses, like Autozone, unfortunately can be using code readers that are unable to read the relevant codes from a Prius, which is why they tell you nothing popped up. Many folks on PriusChat get their own equipment to read codes, and avoid having to depend on a dealer.

If your brake system is involved, you can get those codes by simply pushing a short length of wire into the right terminals of your diagnostic connector, and counting blinks on the dash. A bunch of threads in PriusChat forums give the details.

Since you could feel that the brakes had switched to fail-safe mode, there will be codes indicating why they did that. It is not yet possible to conclude you have a pump failure (an expensive part, also labor-intensive to replace). The brake computer can enter failsafe mode for various reasons. Better to get the codes first, then see whether they indicate the pump, or something else entirely.

-Chap

 

The P0A80 is a code that means replace HV battery, but usually there are other codes to support it.

The C2318 is a 12 V low voltage code, which can imply that the 12 V battery is not in good shape. This may be why they went round the back to look at the 12 V battery.

I have seen it often that mechanics and battery places "test" the battery and come back with the battery is fine, but in the Prius, it proves to other than fine. After replacing the 12 V and all the codes erased, the lights stay off.

However, a P0A80 seldom comes on in error in this circumstance. So what I am saying is the it is likely that your 12 V is not in great shape and it would do no harm to have it replaced, but I think you also may have a HV battery that is also on the verge of needing replaced. I would do the 12 V first and then wait and see if the P0A80 comes back.

The 12 V battery provides power to "boot up" the many computers in the car and then closes the relay to connect the HV battery. After that, the HV battery (via the DC/DC converter) gives voltage to the 12 V battery when the car is in READY. At any other time, there is no connection between the two.

Nothing, except maybe if was badly shorted cause the DC/DC converter (again when in READY) to hopelessly try and charge up a failing 12 V battery.

 

the 12v just boots up the computers and closes the relays, so the hybrid battery is connected to the system.

 

The dealership should have been able to print up a diagnostic report for each of those codes, similar to this one (for somebody else's C2318). As you can see, the system captures a "freeze frame" of relevant information at the instant it recorded the code.

C2318 is a code recorded by the "Transmission Control ECU" (a very grand name for the gizmo that powers the small motor to shift your transmission in and out of Park). In the example I linked above, you can see that other person's 12 volt battery output got drawn down to about 9¼ volts during the process of parking or unparking. In that person's case, several different voltage measurements were similarly low, suggesting it probably was a battery issue rather than a problem with one circuit or fuse.

Your own freeze frame would show what happened in your own case.

If they were recovering from the loss of the only key you had, they may have needed to resort to a procedure that requires the car to be left ON for half an hour or so without starting. That could have been enough to drain your 12 volt battery if they did not remember to connect a charger in advance. (Still, they could have connected the charger in front, without digging around in the back.)

-Chap

 

9 is incredibly low if nothing is on. the only thing a bad 12v does, other than preventing the car from starting, is cause havoc with the computers, which can send false trouble codes and dash lights.

 

In your case most likely as it will have been low for too long.

But a healthy battery that has become drained can be (and should be as soon as possible) charged back up to full. The problem is that few people these days have a battery charger, as they are used to replacing them when they no longer work.

I suspect your battery will be a waste of time trying to charge as I suspect it will not hold the charge and will be back to under 10 V in no time.

A good (AGM) battery with a full charge will have a voltage in the range 12.8 - 13.2 V. A fully discharged battery will be 11.8 - 12.1 V.

 

yes.

 

You could charge it with a battery charger, but if it got that low, it's probably shot and won't hold a charge.

 

This is one of the signs of a HV battery in poor condition. It is consistent with the P0A80 code.

Yes, in the previous post to which you replied the above, we were.

 

I'd change the 12 V battery first and then see what happens with the P0A80.

But if that is still a problem, you can change out the bad module, but it is not as easy as it sounds to do it successfully. Buy a Toyota New battery is the best option, and (IMHO) you should only look at other options if there are extenuating circumstances.

Incidentally, have you owned this car since new, or have you recently purchased it s/h?