2010 Prius check engine & other warning lights

You're inverter pump may be intermittent turning off long enough to allow things to heat up and the code to be thrown and then coming back on whenever and then that may make the code go away until it recodes after it heats again sounds plausible.

 

Personally I’d spring for a dealership assessment, sooner than later.

Regarding the water pump code: wouldn’t hurt to replace engine coolant pump (and thermostat); they’ve been known to let go around your miles.

 

It's no problem to replace It's just you may need to make sure you get one that will last and apparently aftermarket non-dealer blah blah blah turn out to not work so well or for so long I found that out on my generation 2 once I modified the thing and got the right kind of pump that I wanted up in there It's on autopilot

 

P261B is a code for the engine water pump. Not the inverter pump. The one on the front of the gasoline engine that is responsible for cooling it.

Although nobody was retrieving the trouble codes at the time you were driving just then, here is my guess:

The P261B was detected, turning the check engine light on. The engine temperature began to rise because the pump wasn't working.

There is no normal overheat warning light until a temperature of 120℃, but when there's a water pump trouble code, you won't get there, because the ECM will shut the engine right off at 105℃ if a water pump code is present. At that point the power management control ECU (kind of the orchestra conductor for the car) sets code P0A0F, meaning "I don't know what happened exactly, but there's no engine power", and it is stuck using only the battery to move the car. The battery is very puny for being the only thing to move the car, and the car slows way down and feels like it's going to stop (and will, pretty soon, as the battery drains). Several other warning lights come on at the same time, as those ECUs set codes that mean "just got news that the power management control ECU has set a trouble code."

You don't want to keep repeating this, because running the engine without its water pump working right is quite bad for it. Strictly speaking, before just replacing the pump, somebody should make sure there's not something simple wrong with the wiring to the pump. But in a 2010 with 155k miles, if it acts like a bad water pump, no one will be surprised if it's a bad water pump.

 

If an arm and a leg is only worth $100~200, yeah. You've got a nice car, on the cusp of a lot of stuff; something to keep in mind.

 

It sounds like your inverter coolant pump.
You can check the reservoir when the car is running and see if the coolant
is flowing. But it kinda sounds like it's starting to go bad.
You pretty much have to remove the inverter to change it.

 

According to AutoZone (and Google concurs), the code indicates engine coolant pump.

 

Yes, the code that was set is specific to the engine coolant pump, I don't see any reason to think the ECM was lying about that, and the rest of the story after the check engine light came on was consistent with what happens when the engine coolant pump has flaked out and the engine hits 105℃.

Also, inverter coolant pump problems are detected by the power management control ECU directly. The codes it can set for that (P0A93, P0C73, P314A) are all shown in the Diagnostic Trouble Code Chart as lighting both the master warning triangle and the MIL (check engine light). Both those lights would have appeared simultaneously had one of those codes been detected.

For the OP, the MIL/check engine appeared first, and the master warning only later, when the power abruptly dropped off. That's consistent with the ECM reporting P261B first when it detects the low engine water pump RPM, and the power management control ECU only setting P0A0F ("hey! where's my engine power?") and lighting the master warning after the engine hit 105℃ and the ECM shut it down.

 

Diagnosis and repair are two different things. If it’s rodents it can be involved, and nobody works for free.

 

'cept maybe the rodents.

 

Looks right. Did you try the "select my vehicle" or "check fit" features on that page?