I don't really pay close attention to the MPG reading on my dashboard.
This is how I do mine.
setup a spreadsheet
Jot down the mileage reading before I fill up the tank and also jot down how much gas I put in after. Do the same thing next time I fill up the gas. Then calculate it from there.
During summer time I would get around 47mpg City/Highway
Right now I'm getting around 37 City/Highway.
I try to use cruise control as much as I can.

When I brought my car back from the dealer after the firmware update.
the MPG reading was 32.7 MPG then I figure it out after filling up the tank and it came out to about 37MGP.

 

Thanks starman for the suggestion, but I gave up and am taking it back in tomorrow. My mpg is now 24.3 and dropping. I'm beginning to think they guessed the problem and loaded the software update hoping that was the fix.

 

Thanks starman for the suggestion, but I gave up and am taking it back in tomorrow. My mpg is now 24.3 and dropping. I'm beginning to think they guessed the problem and loaded the software update hoping that was the fix.

Was it the HVAC software upgrade? I guess there was one for the '07 that I have. There was no change (still no heat) for me. All they told me was to keep it on auto and "live with it". I guess the hybrid was never made to work in -30C (-22F) weather.

 

Bulletin 09-025, eh? When I brought my '09 into the dealership for its first A1 service, they told me no software updates were available. Wonder if the bulletin is floating around on the internet somewhere..

 

This is a rampant problem with the 09's. Mine started at 23.5K and took it in and they said it was a software problem and upgraded the software. This fixed the light problem and the auto stop feature but killed the mpg. Averaging 44-46 with up to 50.5 on the highway is now 33-35. They might be giving the battery some longevity as they hope but this defeats the purpose as too why I bought the car.

 

I have an 09 HCH and my mileage dropped and my IMA light has come on at 12000 miles and I won't let the dealer "re calibrate". I think Honda needs to recall the 09 HCH for new batteries.

 

Sounds like it is time for us 09 HCH owners to sue Honda! I too have the same problem.

 

I am also having the same problem except my ima light is not on. i have dropped to 28 mpg,this started in august so it's not a "weather" problem. The dealer won't do anything unless they get a trouble code, same response from honda america, i have noticed that i never get full bars on my ima guage anymore. by the way it's a 09 with 8000 miles on it.
If you are serious about sueing honda i'm in

 

Ask and ye shall receive...09-025 should be attached to this post.

I asked for a copy of it today when I took my car in for this same issue: IMA and check engine lights came on twice in the first 12k miles. Dealer would only perform the software update, so I refused it. I asked for the IMA battery to be replaced, and they wouldn't do it without applying the software update first, as per the service bulletin. Of course, that defeats the entire purpose of replacing the battery since the software update kills the MPG anyway.

To the dealer's credit, they did listen to me when I asked them to do nothing to the car before asking me. So I took it back with the IMA and Check Engine lights still on. Hopefully a recall or better solution to this problem comes out soon...but I'm not holding my breath.

 

after reading these post I have to wonder....as my drop in mpg's started the day after i had the first oil change if the dealer did the software update without telling me. Can they do that?