Haven't posted in a while, but my HS has been mighty reliable in the nearly 3 years I've owned it. It has about 57k miles and I think the battery pack might be going bad. I noticed battery life drops faster than usual which is making the engine run more often. My mileage has dropped from 33-35 (manually calculated) to 25-28 (gas light comes on at about 300 miles from a tank full, used to come on at around 400). This is really frustrating since good gas mileage is the main reason I bought this car, and it's now performing worse than the average mid size sedan with a V6.

My guess i s I might have a cell or two going bad, but I'm now thinking of just getting rid of it since the car it's clearly showing its age. Anyone here having battery pack issues?

 

I suggest you check the simple things first. Check tire air pressure. Check the air filter, is it clogged, how long ago was it installed. I recently swapped air filters and mileage increased 4 mpg and the old one was only in 7000 miles, but it was a cheap eBay one. I installed a Fram and mileage went up. When was the oil last changed and did they use the correct 0w20? Did they overfill it?

Have your brakes checked for stuck sliding guide pin or caliper. I just hit 60,000 in mine and did an overdue brake service. Partly because my mileage had dropped.
This involves taking the calipers off, cleaning the slide areas and cleaning and regreasing the caliper slide pins with SylGlide lubricant. I found the driver side rear caliper lower slide pin was seized in the caliper support bracket. Parts alone cost $130, but I do my own work and this was an easy job. A shop should not charge more than an hour or so to service and check your brakes. And my pads had about 3/4 of pad thickness remaining!

Have a shop do an electrical test on your batteries and charging system. And check for stored codes. The hybrid system and battery have an 8 year 150,000 mile warranty.

However, your regular gel battey may be going bad, it costs about $300.

 

That's a pretty big drop, and you didn't specify how quickly it happened. I did notice my car going from ~37mpg indicated to ~34mpg since early June, but I'm guessing it's the arrival of hot/humid weather. I thought maybe there was a switch in gas formula too, but summer blend is supposed to be more energy efficient so it should increase mpg, not decrease it.

Anyway, any HS that's driven reasonably and getting <30mpg is having some kind of problem. Certainly worth paying for an hour of a mechanic's time to check it out. My 2010 is almost at 110k and everything is still working great.

 

OK so this is unusual - I also have a 2010 HS 250H (79,000 miles) and it is doing the same exact thing that 1neeto car is doing. We consistently got 32-36 mpg with ours and the last three tanks, manually calculated, have been in the 26 to 27 range. I replaced the air filter, ran a tank, and was at 27. My 95 SC300 is getting 25, with the infamous in line six with power de jour. I read on a Hybrid site about pulling the fuse to the ECU for a half hour and resetting the computer which helped on a 2010 Prius, but before doing that I will run thru the basics including checking/replacing the spark plugs. I will also check my brakes (I also do my own work). If I come up with anything, I will post.

 

My HS250 has around 95k miles and I have been getting around 26 to 28 mpg. I changed air filter, check tire pressue, change pcv valve and spark plugs, cleaned injectors with bg44k. Spark plugs look burnt out when I pulled them. I am getting around 35 mpg now just like when I bought it in 2013.

 

Thanks for all the replies guys. Yeah I'll check those brake calipers since I'm more than capable of doing the job (I'm a mechanic by trade, I just hate to work on my own cars lol). The air filter has about 12k miles so I'll start there.

 

This feed is very helpful, as I just started noticing the same problems. I have a 2010 HS 250h at about 65,000 miles, and noticed a substantial drop in my mileage the past 3-4 fill ups. I used to very between 410-460 cruising miles, depending on summer/air conditioning use, and fall/winter usage. I am now getting 290-315 cruising mileage. I am not a mechanic by trade and have very little knowledge under the hood, unfortunately. I too have been thinking if it was time to trade this car in before the problems start. I have been a loyal ES customer for 15+ yrs and recently switched over to HS. I love this car, but worry about the hybrid upkeep when my 3 year certified warranty expires here shortly. All of the above sound like great suggestions, but also sounds expensive when I don't do my own work. I recently got an oil change, and air filters replaced, but didn't notice a difference. So if I have to take it to a mechanic, what exactly should I ask them to do please? Thanks for all your comments. Glad to know it's not just me.

 

An easy check on the brakes is to put your hand near (not on) each brake disk right after parking. If one caliper is sticking, that disk will be a lot hotter than the others.

Another culprit, if you also feel that power is down, is a mouse nest in your intake.

 

wait. Mouse nest?

New service and air filter change. Still getting bad mileage. I still need to check the calipers though.

 

That's funny that Magellan55 suggested a mouse nest. I've never heard that before until my Dad's Chrysler Sebring Convertible was giving him a lot of troubles a few years back. He finally took the car to a local mechanic and that was exactly what they found, a mouse nest! It was the craziest thing we had ever heard/seen. Apparently it's a common issues in garages. And his car would sit for months without driving it, as it was an extra car. However, my HS is parked outside and driven more often, so I can't imagine that would happen again, fingers crossed. But definitely worth getting it checked and ruled out. That sucker was gnawing through a variety of my dad's wiring and cost a fortune to fix everything. So I hope that is not either of our current issues. Good luck problem solving. If you figure it out, I would love an update please. I'll do the same, if interested. Thanks everyone!

 

I had a frozen rear brake caliper glide pin on mine at 60,000 miles. I think with hybrids and the pads lasting so long we forget to do a basic brake service every couple years or 20,000 miles. I suggest doing such a brake service as sticking calipers will make a mileage difference.
It just involves taking the calipers apart then clean the pads etc and re-grease the backs and ends where they hit the clips with brake caliper grease. Then pull the slide or glide pins, clean them and re-grease them with Sil-Glyde as it is safe for the rubber.

 

Like some of you advised, I had the car checked again. They had accidentally reset something with AC and so now mileage is up to 38 or so. Also I had him replace the spark plugs after he reset the previous issue.