Inverter water pump failure, and now better fuel economy?

[SW03ES]

Hey all,

My wife called me frantically that her Prius had the CEL as well as the red exclamation mark on, I told her to stop driving it and went to meet her. We had the vehicle towed to Fitzgerald Toyota for service, which we are familiar with and have used many times before.

The inverter water pump had failed, but the inverter was fine. The water pump of course is not covered under the Hybrid warranty and the car is out of powertrain warranty. Thats total BS IMHO, the inverter water pump is clearly a part of the hybrid system. I even asked them what would happen if I just did nothing and waited for the Inverter to fail since that WAS covered. They didn't really have an answer for me.

Well $380 later she's on the road again.

You may or may not remember, I have always thought something was wrong with our Prius because we never really got the mileage others were getting. 46MPG was the absolute top end even when being very careful. Since the repair, the mileage has been MUCH better. For the first time ever we are getting over 50 MPG, and we can now hear the fan running in the back for the battery packs which we NEVER heard before.

Any ideas?

[chich2000]

Mine failed at 40K and was replaced under warranty! I do have the extender warranty but the service manager specifically said it was covered under the hybrid warranty. Wonder if your dealer pulled a fast one on you? I really didn't notice an increase in mpg after the replacement but my A/C is always on in +110℉ heat in AZ. I has been over a year since it was replaced.

[SW03ES]

Naa, with 40k and an '06 it was covered under the powertrain warranty. I called 5 dealers and checked on here as well as elsewhere online. The inverter water pump is definately covered under the powertrain warranty and not the hybrid warranty.

But did you ever feel like I did that the mileage wasn't right before you had it fixed? I have a feeling the cooling system for the Inverter never worked right from day 1 on my car...makes me a little worried about the Inverter's lifespan. I had it in the shop several times back in '04 and they always said everything was operating as it should.

In the winter our fuel economy gets in the 20s, we'll see how it does this year after this repair.

[usbseawolf2000]

Thanks, good to know. Do keep us posted with the MPG.

Have you changed the 12V battery?

[SW03ES]

I will.

No I haven't changed the 12V battery, thats something that I have been meaning to do...

[Rokeby]

SWO3ES,

I'm glad that you got things squared away for better MPGs in warmish
weather -- lately I'd say temps have been more than warmish. A friend
has wondered aloud, "Who left the thermometer on "Hell?"

Originally Posted by SW03ES

In the winter our fuel economy gets in the 20s, we'll see how it does
this year after this repair.

Is that a typo? This is not what I'd expect, unless:
* OAT was around -10 degF, and/or
* trips are only 4-5 miles long and the ICE/cat converter never get
warmed up.

Even at 30 degF, I usually see 45-50 MPGs on my 28 mi. daily round
trip commute.

I hope things get way better in the MPG department this winter.

If you have any say in the matter, have who ever is in charge cut way
back on the snowfall.

[Patrick Wong]

Originally Posted by SW03ES

...I have always thought something was wrong with our Prius because we never really got the mileage others were getting. 46MPG was the absolute top end even when being very careful. Since the repair, the mileage has been MUCH better. For the first time ever we are getting over 50 MPG, and we can now hear the fan running in the back for the battery packs which we NEVER heard before.

My idea is that the 12V battery was disconnected while your car was repaired. This gave the various ECUs a chance to power down and then power back up when power was restored and the car was started.

If you are relying upon indicated mpg per the MFD, that also should reset when the 12V power has turned off. After the power is restored, the mpg readings are tentative and will become more precise as time passes. So, see whether the improved mpg continues over the next couple of months.

Regarding the traction battery fan running at a higher speed than you've previously noticed, maybe the summer weather is hotter this season, or maybe the battery is starting to age so it has less capacity, which results in charging and discharging at a more rapid pace, which produces more heat.

[SW03ES]

Originally Posted by Rokeby

Is that a typo? This is not what I'd expect, unless:
* OAT was around -10 degF, and/or
* trips are only 4-5 miles long and the ICE/cat converter never get
warmed up.

Even at 30 degF, I usually see 45-50 MPGs on my 28 mi. daily round
trip commute.

I hope things get way better in the MPG department this winter.

My wife does drive mainly short trips, but still I wouldn't expect the MPG would get down THAT low, and we're talking about temps in the 30s and 40s here.

If you have any say in the matter, have who ever is in charge cut way
back on the snowfall.

I will definately see what I can do

Originally Posted by Patrick Wong

My idea is that the 12V battery was disconnected while your car was repaired. This gave the various ECUs a chance to power down and then power back up when power was restored and the car was started.

If you are relying upon indicated mpg per the MFD, that also should reset when the 12V power has turned off. After the power is restored, the mpg readings are tentative and will become more precise as time passes. So, see whether the improved mpg continues over the next couple of months.

That could very well be the case, I'll keep watching it and report back.

Regarding the traction battery fan running at a higher speed than you've previously noticed, maybe the summer weather is hotter this season, or maybe the battery is starting to age so it has less capacity, which results in charging and discharging at a more rapid pace, which produces more heat.

Also possible, but we had driven it out to dinner and my wife and I both said at the same time "What the hell is that?" and checked to see if the windows were open in the back. We definately have never heard it run before...ever...could be a coincidence...

[galaxee]

well, it is pretty damn warm around these parts lately, isn't it? if there's anything we can do to help, we're just a short zip down 270 from you now.

[SW03ES]

Are you really? Welcome to the neighborhood! What brought on that change?