[TampaPrius12]

I have a 2012 Prius with 82,000 miles. I was normally getting 49-51 mpg, suddenly my mileage dropped to around 40-42 mpg. I've kept a close eye on it for the past several thousand miles to rule out differences in fuel fill-ups. The decrease seemed to coincide with the recall for a software fix. Could that have had anything to do with it? If so, how? If not, what might?

 

[maberma]

I have a 2012 Prius with 82,000 miles. I was normally getting 49-51 mpg, suddenly my mileage dropped to around 40-42 mpg. I've kept a close eye on it for the past several thousand miles to rule out differences in fuel fill-ups. The decrease seemed to coincide with the recall for a software fix. Could that have had anything to do with it? If so, how? If not, what might?

Wondering if you got this resolved?

 

[WhiteEagle49]

I took my 2014 Prius Two (45,000 miles) to the dealer 03/02/2019 for a recall (18V-684 JOV) software fix that was supposed to remedy a problem associated with sudden loss of power at high speed that might cause an accident. It took them 1.5 hours to complete. I was getting 40 to 45 mpg's around town before the fix. After the fix my mpg's dropped to 30 to 35 mpg's. My driving habits are conservative and I use cruise control when I can. I thought maybe the traction battery pack was failing. I ordered a Carista OBD/Bluetooth device and used the FREE DrPrius app to check the battery status. No codes or engine check light. Batteries are fine except for 1 pair that has a low resistance reading. (I replaced the 12 volt accessory battery in the trunk a year ago and there was no change in mpg's.) After I ran through the Carista app diagnostic check, the mpg's improved to above 40 mpg. Really weird. Wondering if Toyota did something on purpose to make owners trade in their cars. If they did, how can you prove that they did it? I got 44 mpg on a 2 hour interstate 70 mph trip. When it was new, I was getting 50 to 54 mpg's. Of course, the Prius mpg computer's mpg reading is bogus. Actual mpg's are 5 to 7 points lower. Anyone else notice the same difference after the recall service?

 

[maberma]

I took my 2014 Prius Two (45,000 miles) to the dealer 03/02/2019 for a recall (18V-684 JOV) software fix that was supposed to remedy a problem associated with sudden loss of power at high speed that might cause an accident. It took them 1.5 hours to complete. I was getting 40 to 45 mpg's around town before the fix. After the fix my mpg's dropped to 30 to 35 mpg's. My driving habits are conservative and I use cruise control when I can. I thought maybe the traction battery pack was failing. I ordered a Carista OBD/Bluetooth device and used the FREE DrPrius app to check the battery status. No codes or engine check light. Batteries are fine except for 1 pair that has a low resistance reading. (I replaced the 12 volt accessory battery in the trunk a year ago and there was no change in mpg's.) After I ran through the Carista app diagnostic check, the mpg's improved to above 40 mpg. Really weird. Wondering if Toyota did something on purpose to make owners trade in their cars. If they did, how can you prove that they did it? I got 44 mpg on a 2 hour interstate 70 mph trip. When it was new, I was getting 50 to 54 mpg's. Of course, the Prius mpg computer's mpg reading is bogus. Actual mpg's are 5 to 7 points lower. Anyone else notice the same difference after the recall service?

Thanks for the update. My 2012 Prius has about 165k miles on it and gets about 40 mpg around town, and about 42 hwy. That's what the prius dash says.

 

[TampaPrius12]

I'm doubt that Toyota has modified their software to get us to buy new cars I might consider that the installation of the software by the dealership might have been incorrect though, but I'm pretty sure that Toyota would have made it idiot-proof. I am surprised that you have genreally only gotten 40-45 MPH. you run it in the "eco" setting?
I'm wondering if our issue has to do with the fuel formulation.

 

[WhiteEagle49]

Yes. I use the ECO setting all the time. Running the A/C also lowers gas mileage and I use it a lot (Florida).

 

[WhiteEagle49]

We just returned from a trip wherein we drove 150 miles south on I-95 and returned 3 days later. Speed limit was 70 mph. My Prius Two reported 52.5 mpg going south. The trip mpg's went down to 51.5 on the return trip due to head winds. I was surprised and pleased with the result. Actual fuel pump gas mileage will be lower and I will post again with those numbers after my next fill up.