I purchased the car new in December 2007 and was initially pleased. Unfortunately, the performance of the vehicle has decreased significantly, apparently due to a software update installed by Honda on August 2010 (see service bulletin 10-034). Honda states that the software update was intended to extend the life of the hybrid battery but is silent about the obvious adverse impact on gas mileage, power, and emissions. The hybrid integrated motor assist (ima) assist is operating erratically such that when trying to accelerate (e.g., when merging onto an interstate or passing on a highway) the car may have the expected response or a very limited response from the unassisted 1.3 liter engine. Just last week when I was merging onto an interstate one time the ima did not provide any assist and I was concerned due to the fast approaching traffic. I never know whether the car will have the expected acceleration. The ima behavior can vary from minute to minute while driving even under the same conditions. Has dot and NHTSA studied a 2007 Civic hybrid after the software update was applied?.. updated 08-27-12 updated 08/27/12 updated 10/02/12

- Ijamsville, MD, USA

The Honda Civic hybrid 2007 is suddenly unable to accelerate appropriately. This fault is most dangerous when accelerating to start going after red lights and stop signs, especially on hills. It is also noticeable when accelerating to merge into traffic, the acceleration performance of the Honda Civic hybrid declined precipitously and dangerously immediately after Honda required replacement of the ima battery and concurrent new software (at the Honda dealer) in March.

- San Francisco, CA, USA

This vehicle is not safe for highway or city driving. It decelerates when you need power, making it very dangerous to merge in high speed or heavy traffic conditions. In the summer when the A/C is running, acceleration is extremely unreliable. The driver's side has severe blind spots. I have also experienced long delays in the engine restarting after pulling out into traffic from a dead stop at lights or stop signs. I have nearly been hit by oncoming traffic -- planning for adequate gaps in traffic is a challenge and very different from the other vehicles I drive. I am an experienced driver with over 37 years behind the wheel and an excellent driving record. I have owned 4 Honda and this so-called hybrid has been an engineering disaster.

- Freeport, ME, USA

I purchased a new 07 Honda civ hybrid and from the start never got close to the mpg as advertised.I had the car looked at by Honda dealer multiple times and they very found anything wrong and would comment that car was within spec. 21/2 years later and in the summer I experienced when the I was in heavy traffic and high temperature with all electrical options on ac, nav, radio, etc. The hybrid battery would drain and not keep charge and the car would operate sluggish, no power, no acceleration and basically unsafe to drive. Th car drove that it had run out of gas.I experienced this 3X in 2 weeks as I was exploring and documenting the symptoms.I took it back to the dealer and it was the time of the software update.they updated the software and they would not replace the batteries even though we indirectly agreed (dealer mechanic did but not Honda corporate..since they declined to replace battery) over time that the battery had degraded due to design flaw.after the software update the car driving characteristics changes.engine idles at higher rmp (higher keeps the battery better charged), the power to pass a vehicle on the highway (my wife would press on the accelerator to pass a car on the highway and the car did not respond almost causing accidents). Considers it unsafe and refuses to drive it and put kids in it.I had de aler look a it for a few days working with the Honda technical team. Final assessment was did not find anything wrong and it is driving within spec.how can that be?the car no longer has power, cannot dependently pass or overcome a car on the highway in normal driving speeds and when you stress it traffic on a hot day and run the normal equipment ac the car feels like it is running out of gas and the hybrid batteries are not charging and are not operating the car as you would expect a car to operate.the software update made the car worst.the car is unsafe!

- Fairfax Station, VA, USA

The Honda Civic hybrid ima system has been inconsistent and a worry since I bought the car. The charge level varies wildly within minutes, releasing the braking charge mode unexpectedly while traveling downhill, resulting in rapid acceleration. While going uphill the ima system suddenly shows no charge and the engine is unable to keep the car's speed constant, resulting in rapid deceleration. The software update that was said to fix these problems resulting in no change to the problems but a considerable reduction in mpg. The engine refuses to stop at red lights and instead remains at idle - wasting gas. I have service records covering the entire history of this car which documents my concerns and complaints. The Honda service department was never able to find any problems with the ima. I continue to drive this car but am concerned for my safety and the car's reliability. Anything you can do to help identify and remedy the ima problem will be greatly appreciated.

- Santa Barbara, CA, USA

There is a potential for the voltage converter that relays power from the integrated motor assist (ima) system to the vehicle's electrical components to fail..a cvt doesn't actually have gears, so the system uses electronics to direct the transmission to up- or downshift in specific ways when a driver hits a paddle.battery loses charge suddenly and power is significantly lost to the point where acceleration is not possible. This has created several unsafe driving condition in highway and expressway entrances, as I can not get in safely or maintain safe speed during driving. This incident has repeated many times in the past three years. Battery indicator drops to zero bar or one bar and power is lost significantly. Sluggish to poor acceleration, especially in highway merge situations placing owner is dangerous situations. When battery charged at least 50%, acceleration is acceptable as the ima assist in acceleration.the vehicle's hybrid ima system (integrated motor assist) has been steadily deteriorating the hybrid battery system must recharge so frequently that battery assist is available less than half the time. When assist is unavailable, acceleration is dangerously low, making common driving situations such as left turns, freeway onramps, and merging into traffic unpredictable and quite hazardous. Honda's only response has been a series of ineffective software updates. Honda will not replace the battery under warranty unless a warning light appears. Yet even the current severely degraded performance of the battery does not trigger that warning light. I have been in several near miss situations when acceleration was so sluggish that I was nearly unable to evade a dangerous traffic situation.

- Garden Grove, CA, USA

We own a 2007 Honda Civic hybrid. We strongly believe this car is unsafe. In 2010 we brought the car into a Honda dealer after the ima light came on. Instead of replacing a bad hybrid battery, the dealer instead "upgraded" the ima software. As a result, the car has lost mileage. But far more importantly, it has lost any acceleration. The software doesn't use the ima (electric booster motor) in a manner that provides any acceleration to the car. In fact, as best as we can tell, the ima (integrated motor assist) is mostly turned off. So we have a smaller combustion engine than the conventional Honda civic doing the work of what should be two engines. The primary and booster. We constantly have a difficult time in gaining freeway speed to properly merge onto the highway. This is impossible if the on ramp is on a hill or incline. We have had several close calls and near accidents. As a result we firmly believe this car is un-safe. We urge you to open up a safety investigation into the 2007 Honda Civic hybrid. If these hybrid batteries were replaced, as they should have been under warranty, this car would not have a safety acceleration problem. Honda refuses to do so. We need your help. Sincerely,

- Mesa, AZ, USA

This vehicle received a software update to extend the life of the batteries. This update increased the danger of this vehicle more than it had when it was new. The greatest hazard is that this vehicle has unpredictable amounts of power. I had an incident while trying to cross a busy street on an incline with a limited view of oncoming traffic. Normally, the vehicle supplies sufficient power to cross traffic but this time the engine revved high and the car seemed to crawl while traffic was bearing down upon me. Thankfully, the alert oncoming driver avoided hitting me. As for gas mileage, the vehicle never came close to the epa mileage of 51 mpg, the update dropped the mileage down to around 35 mpg.

- Olathe, KS, USA

I have major concern and safety issues with my 2007 hch. It is when the electric motor is not available. I have to look at the hybrid battery indicator to determine if I will have the extra 20 hp needed to maneuver the car around the traffic safely. Also, the car will perform some kind of health check for hybrid battery to recalibrate the hybrid battery indicator. When it does that, it will stop using the electric motor even though the hybrid battery indicator is more than half full charged. That affects my decision on how to maneuver the car around traffic safely. Example 1 I cross a lot of 4 lanes highway with high speed traffic without stop lights. I need all the power that the car can provide with electric motor to quickly cross the 4 lanes highway when there is an opening. Sometime the car will not use the extra 20hp from the electric motor and I would not have the necessary speed to cross the 4 lanes highway without close calls. To be safe, I wait for large gap in the traffic before I can safely cross the highway. Example 2 if it is hot outside and I drive over several hills, the hybrid battery will be depleted by the time I get to the specific intersection. On the right is a bend that is hard to see incoming traffic going 55mph or over. On the left is a long uphill. With the depleted hybrid battery, I do not have the power to quickly pick up the speed going up the hill and if someone is coming around the bend at the right time, they will have to slow down. A semi was not able to slow down in time and had to swerve left to pass me. Lucky, there was no incoming traffic because the semi cannot see incoming traffic as we both were going uphill. The bottom line is that the amount of the power the car has is unpredictable as I may or may not have 20 extra hp from the electric motor.

- Washinton, IL, USA

The car became unsafe to drive following Honda's software update 10-034. All owners were asked to have the update performed to prevent hybrid pack deterioration. The letter listed multiple situations in which hybrid assist and braking will be reduced. As a result of the update the car has markedly reduced assist, and at unpredictable times no assist whatsoever. At least once a day, at a random time, battery soc drops to 2 bars, all assist is disabled and then the so-called recalibration is performed where the car fully charges the battery to 5 bars, then jumps to full 8. on average that last about 8-10 minutes as documented in multiple youtube videos on the subject. During all that time no assist is available, and additional gas engine power is being used to charge the pack. The gas mileage suffers as well as I am driving at 3-4K RPM instead of the usual 1-2K.. I've experienced multiple situations where such a drop happens when trying to merge on an uphill highway with vehicles behind me almost rear-ending me while I am flooring the gas pedal. I've had that happen before left turn when after a quick glance on the gauge and seeing it full, I'd start turning only to see the pack drop and the car slow down significantly. A related problem is reduced/unpredictable braking. When the battery is cold and the car idles higher than usually, all regenerative braking is disabled and it takes a significant effort from the driver to stop the car. Multiple complaints to the dealer were met with "operating as designed" and "the update does reduce the power". lately, I've been simply referred to become a party of class action suit against Honda, as the dealership is unable to help with anything listed in that suit. As a summary, the car has unpredictable losses of braking and acceleration and a markedly reduced mileage which undoubtedly violates epa rules.

- Penfield, NY, USA

Ever since Honda did a software update on my car's engine to extend the life of the battery, my car has had intermittent accelerations issues. For example, last summer, I was at a stop light and when it turned green, my car didn't seem to want to "go". I had to press on the gas pedal about 3 times to get it to "engage" and actually move. Many times the car is sluggish to start from a stop, or accelerate, but it does "go", just not as promptly and quickly as it should. The most recent incidents occurred last month and has prompted this complaint. Both involved merging onto a freeway. In the first instance, I was in the right lane, which I knew would turn exit only a mile or so down the road. There was a truck on my left, followed by a long line of slow moving cars. So I thought, since the truck was right next to me, I would speed up a little bit and bit and get in front of it. To speed up only fast enough to pass this truck, my car revved to over 6000 RPM. It just didn't want to accelerate normally. I did safely make the lane change in front of the truck; the worst thing that would have happened in this case was getting off at an exit I did not intend to get off at. However, the next day, I was merging onto freeway traffic with a typical lane length to allow merging. My car didn't want to accelerate enough to safely accomplish the merge. I had to rev the engine up to over 5000 RPM just to get up to barely 45 mph to accomplish the merge. I feel it is only a matter of time before I get into an accident because of this acceleration issue.

- Elk Grove, CA, USA

Battery loses charge suddenly and power is significantly lost to the point where acceleration is not possible. This has created several unsafe driving condition in highway and expressway entrances, as I can not get in safely or maintain safe speed during driving. This incident has repeated many times in the past three years. Battery indicator drops to zero bar or one bar and power is lost significantly.

- Yorba Linda, CA, USA

The contact owns a 2007 Honda Civic hybrid. The contact stated that a software update was performed by the dealer. The contact stated that the update decreased acceleration and shortened the battery life of the vehicle. The contact believed the failure was a manufacturing defect. The failure mileage was 99,500. The consumer stated the update caused poor gas mileage. The consumer stated he was getting on average, 42.5 mpg and since the software update, he now gets 36 mpg. Also, the battery continually depletes quickly to the point where it is showing only one to two bars, causing further performance/power issues. It then slowly recharges. Updated 10/14/11 updated 10/31/11 updated 12/19/11

- Bath, PA, USA