Gas engine shuts off, battery depletes, hybrid shuts off

The P261B code is for the engine coolant water pump. You said your car has 242k miles on it. Replace your water pump with a new OEM pump.

Install new engine coolant and you should be good to go.

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Hi Lisa,

Imho, if your Husband can replace the water pump, have him do that. Then fully charge the 12volt battery. Go for a short drive.
Then, start any further diagnosis from there.

Otherwise, see a Dealer Toyota Hybrid Expert near you - before you spend any more money.

Hybrid and EV systems are similar, and different, compared to traditional gasoline engine-based systems.
Imho, in your case, you need a Prius Expert.
Otherwise, you may get lucky. But, much more likely you will not.


Good Luck!

 

Are they using Techstream for diagnosis? Very few other scanners are as effective on a hybrid. Any sign of overheating like coolant loss or spills around the reservoir?

I agree with others that you would be money ahead to allow the dealer to diagnosis the issue. Your guy could then do a repair if desired. I especially would not start probing the wiring harnesses for no specific reason. Often false codes are generated when the root cause has initiated a failure.

 

At least 2 of the 4 dtc (Diagnostic Trouble Codes) you posted that have dtc sub codes. And with the sub codes they would look something like C1259 / 58, C1310 / 52 < which are one of those codes common subcodes. There are usually a least several other sub codes per dtc that can mean different issues. The other two codes might also have sub codes also, and Techstream is the best bet to get the information from the cars computers when it's not clear from using another scan tool, exactly what the issue(s) is / are.
Without the relevant sub codes it's hard for any of us to make even educated guesses from the info posted so far..

Edit: @chap and @Brian1954 thanks for posting the explanation and solution that the rest of us were not certain of.

 

If we knew more about your location than just "Florida," perhaps someone could recommend a good shop. I know one that I like so much I started working part time there. But if you're in Pensacola or Key West, that wouldn't help you.

 

Like others have said, get a proper diagnosis by a trained Toyota tech experienced in the Prius. The Techstream tool is far better than an ordinary OBD scanner. If you change the ECM without knowing it is faulty, all you'll end up with is a lighter wallet. Don't just throw parts at codes blindly.

 

The P261B code that you have means there is a problem with the engine cooling water pump and the ECM knows it. The P0A0F, C1259, and C1310 are fully predictable downstream consequences of that, and they don't mean anything else is also wrong. Here's what's going on:

Whenever the ECM knows there is a water pump problem, the ECM will shut the engine down hard the instant the temperature reaches 105 ℃ (221 ℉)—see this thread for the details. That's not considered an overly high temperature in normal circumstances, but when the water pump isn't working, it's bad news.

The power management control ECU is a different computer in the car; essentially, it's the orchestra conductor. It gives cues to the ECM (engine control module) about how much engine power is wanted, and coordinates that with the electric motors and brakes.

When the ECM decides to shut the engine down because of temperature and a water pump problem, the power management control ECU doesn't really know that whole story. It only knows "I gave the engine a cue to come in and it didn't." That's what the P0A0F means. So the car can then only run on the battery, and only until the battery charge is used up.

The skid ECU (which controls the brakes) has to coordinate with the power management control ECU in order to share the job of braking with regeneration. If the power management control ECU is reporting any kind of problem with the hybrid system, the skid ECU needs to know that, and take over full responsibility for stopping the car. So whenever the skid ECU sees that the power management control ECU has a trouble code (in this case the P0A0F), then the skid ECU sets two codes, C1259 and C1310, which essentially mean "roger, I see the power management control ECU has a trouble code, I am taking over full braking responsibility".

So that is why you have all of those codes, starting with the P261B and the rest happening after the engine warms to 105 ℃.

By the way, running the engine with no water circulation is no good for the engine (which is why the ECM shuts it down at 105 ℃, but it's no good for the engine even before that), and then continuing to drive until the battery is flat spent is no good for the battery. So it is important to get that pump replaced ASAP so those things stop happening.

 

Thank you @ChapmanF for clearly explaining what happenes to trigger the 4 trouble codes in Lisa B. 's Prius. You explain things much better than I can. I am still learning about how the Prius works even though I have owned my 2011 Gen 3 since it was new.

@Lisa B. , replace the water pump and hopefully your HV battery has enough "power" left in it to start the car. Make sure you disconect the 12v battery to clear the trouble codes or use a scan tool to clear the codes. Then drive your car to make sure that no trouble codes reappear.

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Sounds like a water pump issue. It’s the easiest water pump I have ever done.

 

I have personally seen the same thing happen on a test drive of a prius. The dude took the cat off of the car so it wouldnt get stolen and when he put it back on the coolant came out of the bottom heater hoses and he forgot to add coolant. The car will shut down to avoid overheat and wont move until the code is cleared. You probably have a recall on your inverter as well as I think the recall was to avoid having the car stuck on the road and wont move.

Start with water pump. See if it runs and the impeller is good. Replace as necessary, burp the coolant and clear the codes and test it.