P0A93 code, inverter pump still running, car seems fine, now what?

P0A93 indicates your HV inverter coolant pump (and not the ICE coolant pump) is not working properly and needs to be replaced. How long have you owned this Prius? Most owners knew about a limited service campaign for replacing the inverter coolant pump for free at a Toyota dealership. I had mine done three years ago.

Don't delay installing a new one. You're almost certain to overheat the inverter if you wait - especially in the Lone Star state in summer!

 

As you know, P0A93 means that the inverter is overheating. The inverter pump is the usual cause of that overheating. Since you say that there is fluid movement in the reservoir and can feel vibration from the pump running, let's assume the pump is OK for now. A few questions:

1. Odometer reading?
2. Did you check the engine coolant level in the radiator? If not, see how low the coolant is, and fill to the top of the radiator neck as needed.
3. Was your inverter pump replaced earlier, under the recall program that had been in effect a couple of years ago?
4. Set the cabin air temperature to MAX COLD and turn the AC compressor button on. Are both radiator fans are running, and if so, are they blowing air towards the engine?

The point of questions 2 and 4 is to see whether there exist any residual problems with the engine cooling system that might have an impact on the inverter overheating.

 

I wouldn't say that the fluid should look like it is boiling but it should show some turbulence. If you don't see that, maybe the coolant should be drained and refilled. If that doesn't help then the pump might need to be replaced again.

If you wish to DIY, that procedure is not too difficult, and I have posted on how to replace the inverter coolant pump. The hoses between the inverter, transaxle, coolant pump and radiator should also be inspected while the coolant is being drained.

 

No, it doesn't, any version from 7 onwards should cover your 2007 Prius. Most of the updates are to accommodate new models. Having said that bugs are fixed and new features added, so see what you have and update if you see something nice (e. g. from other's screenshots) then you can always update. Seeing as you are starting fresh, I'd d/l the latest available version and install that.

All the best.

 

I just replaced my inverter pump last week but I am getting the P0A93 code. My question is when checking the inverter coolant tank for movement does the engine need to be running or just the car being on and in "ready"?

 

The pump should run any time the car is "ready".

After you replaced the pump, did you bleed the inverter cooling system? There's a bleeder screw attached to the front of the inverter (towards the radiator).

I put a piece of small diameter hose on the end of the bleeder and the other end into the inverter coolant tank. Power up the car then open the bleeder.

It can take several minutes to get all the air out - you can hear the pump get less noisy.

Also remember, that a P0A93 means the inverter got hot, and anything wrong with the cooling system can cause it. A clog in the system, dirt or leaves in (lower) front of the radiator, a kinked hose, etc.

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Replaced with what? I tried a Dorman and found that sometimes it didn't start when the car did. It would do just what you are observing, a P0A93 code is logged when there is a no-start on the pump, but the next time the car starts there is motion in the coolant reservoir. Too unreliable for my taste (didn't want to check for motion under the hood every time the car is used) so it was replaced with an OEM pump and no problems since.

 

Good to know. I've had intermittent problems as well and was unsure if replacing the pump would solve it.

 

I've had this too. The catch was that my pump worked intermittently. Sometimes I'd raise the hood, look into the reservoir, and the fluid would be moving. Other times it wouldn't. I think it only worked on max and not lower speeds, as it seems to vary its speed when working right. I replaced it with a new one and still have the old pump just in case. This one was an autozone one that lasted only a couple of years.

 

I don't understand at all: it is very simple, car start, then lift the hood, open the stinky cap and look down, there should be some kind of bubble on your inverter reservoir fluid => then the inverter pump WORKs.

If there is no bubble, then it failed . If you roll your dice, then YMMV .

ev-

 

If the light is not good it can be very hard to see that motion.

I have a vague recollection that somebody here observed that if the fluid level wasn't right there might not be any motion visible in the reservoir fluid even with a good pump. However, I couldn't find the post (too many matching the keywords) and don't recall if high fluid or low fluid made the motion hard to see.

I once considered making some device to drop in the reservoir (the original idea was a small plastic boat a little smaller than a cough syrup measuring cup, with a straw glued to it for easy removal) which would move (not sure how, exactly) if the pump was running. In the end decided not to try it lest the device introduce contaminants into the system - or sink.

 

Here is my take : zoom to 47 secs.
youtube prius inverter pump check - Google Search

I am sure someone will dispute a old pump will perform less turbulence but, once you really check, you know .

Someone even suggest to perform check as a routine ( oil level, belt, ... ) : YMMV.

Think about it, would you drive the car, knowing the belt is loose , and you water pump is not turning ?

 

My mileage did vary when the pump's operation was intermittent! It took multiple inspections of the fluid's motion over time because I had the hunch that the pump wasn't consistently running.

 

FYI: that is exactly what I try to say ... the pump run and generate visible bubble every time the engine on : there is no intermittent.

 

P0A93 only tells you temperature inside the inverter got too high.

Often that will be because of the pump, but sometimes it isn't. Then you have to continue with other possibilities. Do the cooling fans behind the radiator work? Is there some blockage in the inverter/transaxle cooling passages. (There's a thread somewhere here where somebody took one of the hoses off and for some random reason there was a bolt inside.) And so on.