The dreaded IMA light and malfunction indicator lamp has been on for months. Sometimes they go out for weeks then comes back on. However on two occasions by battery light glows red when I am idling and the car, Civic 04 hybrid, is hard to start. That went away on its own the first time. The second time, I had the 12 V battery checked. It was ok but low on charge although it had been running. Also the green charge lights and the blue gas usage dashboard lights had stopped working. I got a jump start and everything worked fine for several weeks (although IMA and malfunction light stayed on). However, the mileage dropped by about 4 mpg. Once again weeks later,the battery light came on and hard to start. I charged the battery and once again it was ok but I am very insecure that it might happen again far from home.
I had checked codes before and the puzzling 1600 and I forgot the other, but neither idicated a specific problem.
I plan to take it in for repairs but would like some idea of what the problem is before I do. Any ideas?

 

Most likely you have a p1433 or p1435 code with that p1600, meaning your hybrid battery is dead and needs replaced. That's also why your IMA isn't working to show you indication of charge/discharge and your 12V isn't charging.

You're looking at $3600 from dealer, or $1000/$2000 from www.hybridbatteryrepair.com.

Better yet, do what I did. Get your light to go off, and then trade in the car for a new one.