I have a 2004 Honda Civic hybrid and recently, after the warranty expired, experienced problems: the IMA (Integrated Motor Assist)and check engine light came on. You'll need to go to a Honda dealer for assistance, parts and repairs. The two reputable auto shops, I used, could not find the faults using their diagnostic systems. This vehicle was well maintained and not abused or run hard and miles were driven on highways. Note: transmission fluid was approx. $16.00 per quart. The NiMH battery started showing signs of not holding a charge shortly before the warranty expiration (80,000) and stopped functioning properly at about 84,000 miles. This reduced the fuel economy from 40 MPG to 34 MPG. Replacement batteries are approximately $4,000. In my opinion, the Honda Hybrid is not worth the extra cost. Buy a CIVIC (standard) instead. Any savings in fuel is quickly lost when the battery goes bad.
The 2007 Honda Civic Hybrid is still being advertised as 40/45 mpg (which is why I bought it), but Honda updated the software which changed that rating. I get about 32 mpg now. Had I known that before purchasing this vehicle, I would have bought a Prius instead.
The 2012 Honda Civic Hybrid is a great commuter car. It's durable with easily-replaced parts, comes with a lot of neat features as part of the base package, and gets great gas mileage even without modifying your driving style. When I first started driving it, I averaged 41 mpg, a little under the 44 mpg the vehicle's advertised at- however, by monitoring the fuel-usage display on the dashboard as I drove, I quickly learned to modify my driving to be more efficient. I've gotten up to 56 mpg. Cautionary note: be aware that the life of the lithium-ion battery pack is only about 100,000 miles. If you have your car for longer, you'll eventually need to replace it, which will run several thousand dollars if it's not under warranty.