chromedome

That's pulse and glide, I use it on my regular commute and I'm getting 45 mpg right now. The key is to accelerate on engine power and glide on battery power. Driving slowly in EV mode is ok for short distances but running on battery for a long distance actually wastes more fuel in the end.

Vegasaurus

if an individual cells' voltage is low, or there is any other HV battery issue for that matter, you will get a CEL long before you notice any MPG difference. clear the code and it will come back in less than a half hour.

you cannot check individual cell health of the HV battery with Torque or DashCommand, it's a generic code that just says check HV battery. you need a miniVCI to monitor individual cell voltage.

the problem is likely in the driver's seat. hybrids drive differently than other cars. if you drive it like a regular car you will get poor results. if you drive it like a hypermiler you will get poor results.

i recommend taking it out of eco mode and never using EV mode. EV mode puts unnecessary strain on the HV battery. eco mode forces you to floor it to safely merge onto the freeway.

just use normal mode and get used to the way it drives.

that's part of your problem right there.

Maikerusan

I suggest ECO mode most of the time. Use normal or sport for highway spurts.

chromedome

It is possible to check cell health by using custom OBD commands with Torque. You can also use a Bluetooth OBD terminal app to issue commands and read data directly, although it's not in a human readable format and you have to calculate the result by hand. You can use Prius 3rd gen or Camry hybrid OBD commands, I think I got my list from PriusChat.

I've attached a screenshot from the Elmbasic terminal app running on my Android phone. The 2181 and 2195 commands dump battery voltage and resistance. I plugged these numbers into a spreadsheet and I got 15.5-15.6 V and 0.025 ohm on average.

zes

What is your tire pressure?
Another possibility is that your brakes are dragging. Get the car on a level road and put it in neutral. Then with the engine off, see if it moves if a couple of people push it. If it is very difficult to push the brakes are dragging and this can be a reason.
Another possibility is that you have oil of too high viscosity. Is the oil Oem synthetic 0W ?

swfla

iTrader: (1)

I got Lexus customer service involved. For this type of issue, unless the dealer's computer finds a fault indicating a problem, there's nothing Lexus corporate can or will do. They won't send a regional "expert" to the dealer to try a fresh set of eyes and brains on the issue. I recently posted here under the Customer Service forum and Lexus didn't allow my concern to post for others to see. I was very objective with the post and not ranting like an ***. Very disappointed in Lexus's handling of this issue. All I can do is bring it in monthly or so for the dealer to put it on the computer and hope something shows up eventually.

Arty101

Reading your posts, this sounds like this is your first hybrid? If so, it takes certain style of driving, and not just on the Eco mode. Chrome and others in the past use pulse and glide to up their mpg for hybrids. You may want to look at the Prius forums or google about how others drive to improve their fuel economy.

Although this may not be the answer you're looking for, I doubt its a battery problem. Your battery meter will typically operate between 20-80%, and may reach up to 100% going down long hills or drives. I've only achieve that a few times. Also your hybrid battery is warranted for 100K or higher in Calif.

TechNut

We average about 37 MPG in our ES (mostly city driving) so I understand the frustration. We leave it Eco and do some pulse and glide but not very aggressively. Mostly just drive it. It definitely sounds like something is off. It is hard to imagine the battery causing this. The tires can also have an impact of course as others have already mentioned.

Our NX 300h has the same basic drivetrain, with the addition of an electric motor for the rear wheels, so it is less aerodynamic and nearly 600 pounds heavier. We leave it in Eco mode as well and still average 33 MPG. Your 28 sounds more like a 350 rather than a 300h.

montyf

My 2013 300h has 70k miles & is seeing a reduction of 7-10% since new - no change in driver or route
today is shows 36.0 mpg on current tank.
anyone have experience with decline in efficiency as car approaches 100k miles?

jollick

I only have 30 some thousand miles on mine. I have noticed a drop in my average mpg from 36 to 34 this summer, that did not occur last summer. I calculate every fill-up and record it on the fuelly app but I only gas up once every 3 weeks or so. If I were you, I would ask your dealer to test the cells in battery as one or more could be getting weak. I have read on Prius sites that a decrease in efficiency could be attributed to a bad cell(s). Keep us posted on your findings.

swfla

iTrader: (1)

UPDATE:
Corporate called me and sent out a regional tech with laptop. We took a 8 mile test drive together. First half was gradually downhill towards the ocean in city driving. Return trip slightly uphill. Grateful that Lexus did this. But, the downhill leg showed 36 mpg realtime on the tech's laptop and about 31 uphill. I understand uphill being low but got no explanation why the downhill test didn't give the full 40 mpg. Tires are OEM at proper pressure and proper oil, clean air filter. I mentioned wheel bearings and brakes dragging as possibilities but was quickly dismissed by the tech. I'd love for the problem to be my driving so I can adjust that but the tech said I was driving gently enough. I'm enjoying the car and not letting this situation ruin my day. I figure I'm spending an extra $200 a year due to fuel economy. Not large enough to let it ruin my day.