Latest Software Update Safety Recall Resulting in 8mpg less...

You might want to check your air pressure. Those rascals love to reset it to factory standards. Seem to recall a post similar to yours a few days ago in the Gen III section about the latest recall. They did our Gen III before I bought it. Average high 40's and still breaking it in.

Ron (dorunron)

 

If you figure out what is going on, please post what you learned. That way the whole community can benefit from your research.

Sorry to hear the air pressure wasn't it. 10 MPG drop is nothing to laugh about. Have you considered discussing this with your local Toyota representative?

Who has done their recall? | Page 6 | PriusChat Read that page, one of the poster who a 2010 is also saying he is having a drop in MPG.

Ron

 

It's possible (though not necessary) that they disconnected the 12V battery to do the update, in which case the car may need to "re-learn" your driving habits. Did you have to reset your radio presets?

 

The first step is to measure your Prius mileage on a 10 mile course, warmed up, on cruise control:


If your car has a problem, how does it compare to my baseline?

Bob Wilson

 

i would take it back and ask the to reverse it. i don't think this 'update' is worthwhile anyway. if you have to, reset your trip average and make the service manager take a ride with you. all the best!

 

i thought it was to prevent premature inverter failure due to high speed/high acceleration?

 

Check the parking brake.

 

Mine had the update when I bought it new last month. I have gotten between 51 and 54 mpg with the first 3 tanks. Just filled it up and have around 1600 total miles. I would take it in and have Toyota check it over.

 

I also agree that you really need to take your Prius in and have it checked out. I too own a Gen III which has had the EOE recall done on it. I am still breaking it in as it has less than 800 miles on it. My overall average which includes a high speed trip of 240 miles driving at posted limits of 75 miles per hour is plainly shown below at 46.9 MPG. With that said, it seems that your Prius is indeed not operating properly and should be checked out by a Toyota representative.

33 - 35 Miles Per Gallon is way off of what a Prius should deliver. Until you get it checked out, you won't know exactly what happened and why the Prius is operating the way it currently is.

I would venture to guess that the computer that maintains the air/fuel ratio is running the ICE on a rich mix at all times, and that the VTC is probably out of whack too. It is possible that there might have been a glitch with a computer during the update of your car.

There have been a couple of post's of the EOE recall gone bad whereas the computer malfunctioned that was connected to the Prius and actually wiped out (crashed) it's corresponding computer or ECU on the Prius that was being updated. Since we deal with a machine that is controlled by several computers, it is logical to think that something is amiss in all of this.

Only through close diagnostics will Toyota be able to determine exactly where the problems lies. I suspect that if they simply re flashed the system, all would be well. In other words, do the recall procedure twice. Computers are a wonderful tool, however the programming is critical. One wrong bit or byte, and the whole thing is not working like it should.

Ron (dorunron)

 

Someone in the know posted previously that the recall consists of two separate flashes. The first flash has to be completed before starting the second flash. Perhaps this wasn't done correctly on your Prius?

SCH-I535

 

Repeating the benchmark determines if there is a problem with the car. Only two speeds are needed, one slower than 45 mph and one above. Below 45 mph lets us know if there is a hybrid control law problem. Above 45 mph lets us understand if there is an engine or drive train problem.

Bob Wilson

 

They supposedly did mine when I went in for my 10000 mile service last month and I don't notice any difference. I wonder if they really did it since I was in and out in about 45 minutes. How would I really know if they didn't do it but said they did. Oh well, still runs fine so I'm not too concerned as long as I don't get stranded some remote place at a bad time. Sorry you're having problems and hope you get it figured out.

 

Even though I can say...I've had the update and this hasn't happened to me, I'm going to refrain from harping on this reality.

I would speculate however that Toyota is HIGHLY aware of the importance of fuel economy and the MPG of The Prius, and I doubt they would launch a software update that would impact their halo hybrid and iconic brand leader "Prius" by reducing the MPG by 10. The outcry and negative publicity would kill them.

So going back and just saying that your results do not seem typical for the majority that have had the update done, then I would assume something went wrong.

Have you noticed any other behavioral changes in the vehicle?

As already noted..there have been some threads where the update evidently went wrong. I'd recommend at least starting the documentation with your dealership and Toyota in regards to you MPG drop.