My new-to-me 2006 Prius has dropped in mileage over the last few months - a LOT. A couple of days ago, the "Maint Reqd" light went on so I'm not sure what's up (I'll have it checked asap). The car seems to be functioning fine aside from the mileage issue. What I'm wondering is if the Maint Reqd light is likely connected to the mileage, and what is the normal mileage drop for winter. I'm now logging averages in the mid 20s maybe low 30s on a good day. I live in Washington DC and the winter has been brutal. Also, we are very seldom car drivers - once a couple of days - and usually for short hauls - 5-10 miles per trip perhaps. Roads are bad, I'm often in a hurry to get my kiddo to school... I noticed, when I started driving the car after we purchased it in the summer, the average mileage has been steadily dropping which I attribute to the difference in driving styles and usage profile between me and the previous owner. When we started driving the car, the average on the info screen was 47, now, after a few months and a brutal winter, it's 32 and dropping. Is this too low? I had a tank recently with only 25 mpg, and the tank I'm currently on may not even make 200 miles! I have read the forums about why this happens, but I couldn't find anywhere that stated how much is the "normal" drop in mileage during the winter.
Remember, your fuel tank has a bladder that contracts as the temp dives, you lose at least 10% of your storage capacity, depending on your usual mpgs, there's a 10% hit already, add another 10% at least for the cold and now your at 20%, having an "ice" block heater will help especially for short trips. Err, the red light of death is a game changer, either go to a dealer, get an obd2 reader or stop at a good auto parts store for a read
The most typical drop is about 20%. However, your driving patterns should lead to a greater loss than that. Short trips kill efficiency in any vehicle, hybrid, plugin or old fashioned ICE. Your Prius gets its worst mileage in the first 5 miles or so. This does not mean there isn't something else going on. Hopefully another owner with similar short trips can give you a better idea if what you are seeing is typical for that driving pattern.
That's a big drop, you should see about 10 to 15 mpg loss at the most. You have something else going on with your Prius, take it to the stealership to check it out.
"Maint Required" means it's due for an oil change. No big deal to do yourself or anywhere just so they don't over fill it.
My 2004 Prius averages 46 MPG (high 40's in warm weather; low 40's to high 30's in the cold). If the drop is more than 25% you either do not have Low Rolling Resistance (LRR) tires which have a rubber compound that stays soft in cold weather or are not keeping your air pressure (PSI) up as your tire PSI will always drop in cold weather and low PSI will lower your MPG. I always run my tires ate 42(front) and 40(rear) to improve handling, increase tread life and increase MPG with a little sacrifice of feeling more bumps in the road. JeffD
Hi Scott we are also getting really stinky MPG this year in DC area, like yours, but part of our "problem" is my wife stopped commuting to work, so now alls we have is lots of 2-3 miles short trips in NoVA. What you can do is warm the car up and then get out on the Beltway you should be hitting near the 50 MPG at ~60 MPH after 15-minutes or so (3 time segments on the MFD). Figure in the summer not only is MPG better, but we go on longer trips so it compounds the issue. Also keep in mind we have Winter E10 Reformulated Gasoline which is about the lowest energy content gasoline on the planet.
If you were to design a method to minimize MPGs you have done it: short trips in the cold. Best to look at the bright side: "Normal' for your neighbors with SUVs is often 5-10mpg (with the identical conditions and trip lengths). "Maint Reqd" means maintenance required, and is almost always the reminder for an oil change that must be performed between 5,000-10,000 mile intervals (but you knew that from searching the many interesting discussions on this forum and reading your owner's manuals). NOTE: Winters are never brutal in DC -- you had some snow with a little freezing -- best to ask northerners about the true definition of "brutal winter"!
Winter driving delivers a multi-sided punch to fuel economy, especially with a parallel hybrid like the Prius. Gasoline engines, gearboxes and differentials don't turn as easily when it's cold (all cars experience this), but cold also reduces the effectiveness of batteries. Cabin heat use is another detriment to fuel economy, by both drawing precious heat from the engine and causing it to run more than otherwise needed. Add surface conditions to the mix (snow, slush and water drastically increase rolling resistance), and it's possible for for fuel economy to be half or less of clear, summer driving. Not all winter driving is the same. Clear roads in winter temperatures can still deliver 40-60 mpg on 20+ minute trips, but plowing through snow every day can easily half that.
My *other* car a minivan (rated 20 MPG) easily gets as low as 12 MPG in winter, and I think it would be under 10 MPG if I was doing the same short trips we are doing the Prius getting 30-35 MPG. The minivan has longer trips to achieve that 12 MPG.
Thank you all for commenting. It's comforting, in a weird sort of way, to know that other drivers get crappy mileage in these same conditions. Good point about the tire pressure; I haven't checked that for a while. And yes, the winter has been pretty tough. Sure, it's not like the winters I lived through in Minnesota, but we've had some days at sub zero - and when your apartment is designed for a tropical climate, it's no fun. Luckily we had a warm day today so maybe spring is on the way.
