Hi, I have a 2005 accord hybrid with ~120k miles on it. About two weeks ago my IMA and emissions lights came on, I took it to a shop and the OBD threw out a whole series of codes. The tech didn't have much time to look into the issue but said that he thinks its a deteriorating battery, he tried resetting the system and said the warning came right back. When I got into the car the warning had mysteriously dissappeared and the tech had no idea as to how/why.
Today, the lights came back on. I am hesitant to think it's the battery since the battery charges beautifully, discharges at its normal rate and autostop kicks on with no issue. The only difference I can see is that the eco won't kick in.

I am not sure if it is related or not, but thought I would also mention that about 5 times in the past 4 years I will start my car and hear a loud rattling sound which dissappears about 1-2 minutes after the car is started. Two of these 5 times have been within the last week and usually it is on a colder day (I'm in southern cali so I can't really claim that it's a COLD day, just colder than the norm for so cal).

Does anyone have any ideas? I could be more easily convinced i have a sensor or catalatyic converter issue than a battery issue but any advice/input would be appreciated.

 

Welcome to the forums.

Can you get the trouble codes and post the actual code numbers?

 

The rattling sound may be due the intermediate shaft heat shield loose in its mounting bushing. See service bulletin :

http://www.urvi.net/forumfiles/SB/A07-028.PDF

There are several other service bulletins regarding IMA battery software and hardware updates. So, if you have the codes, it may help better indicator what may be the problem.