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Civic hybrid 2008 software update

I had the Honda recommended software upgrade done on the car in July 2010 and have taken it back twice to two different Honda dealers more than once. The gas mileage has dropped from 44 to 40 consistently for the same route and driving conditions on my daily commute. Worst still the car’s power has suffered as the battery does not kick in as often so it struggles going up a hill. The battery is in charge mode more quickly at roughly 50% life so it is not available to boost the power, prior it would not stsrt recharging until much lower like 20% left. In fact I have had to turn around on hills that it could manuever before as it would not go up hill after the upgrade. I have spoken to several other drivers of the same model that say they have the same problem. The software upgrade was to lengthen the life of the battery pack not kill the power and MPG of the car. Any recommendtaions on how to fix since Honda is of no assistance?

This is becoming a familiar story; Civic hybrid software “update” reduces mileage.

However, I’ve never heard anyone claiming his or her car won’t go up a hill anymore. Are you saying the gasoline engine is insufficient to drive the car up a hill? What sort of hill are we talking about?

I’ve driven cars with really small engines, and none of them has ever been unable to climb a hill on a paved road. It may have required second gear, or even first, but it’s hard for me to believe that a 2008 Civic can’t make its way up a hill.

It won’t climb a wall, but it should climb a hill.

Please elaborate.

You answered your own question:

The purpose of the software update was to lengthen the life of the battery.
This means that the gas engine now has to work more often than it did before the software update, because the gas engine now has to replace the electric motor that is no longer being used.

This means that you are going to get lower gas mileage, and there’s nothing that can be done about it, short of going back to the original software version, which I’m sure Honda will not do, because they are more concerned about your battery lasting as long as it can, and their desire to not have to replace it under warranty.


I noticed the same dramatic drop immediately after the IMA system was reprogrammed. A bulletin for this was issued in August of 2010. The IMA system had to be changed because the hybrid batteries were dying prematurely, which would have resulted in Honda having to replace them under warranty.

Following the update, I noticed that the IMA does not kick is when it used to. If the battery meter is at half or less, the IMA does not kick in at all. Honda told me I should only see a difference when idling at a stop.

The battery is not being utilized in order to save life, which results in an increased fuel cost for the consumer, which I feel is not fair.

Anyone who has this problem should report it to their dealer and Honda customer service. I have yet to get the impression that Honda is willing to do anything about it. I have also reported this to the Better Business Bureau Auto Line and my state Attorney General consumer complaint line.

If enough people complain, they will have to do something about it. My dealer said that they have had many complaints.