I'm a newbie here and have a 2004 HCH Manual that just turned over 85,000 miles. I bought the car in 2006 with 53,000 miles, from a local Honda Certified Used Car dealer. The car has seen mostly urban driving cycles the past 2 years, with the occasional bi-monthly highway trip. A/C does see seasonal use in May-Sept.

On a side note: I recently replaced the under-hood 12V battery (this was NOT really necessary, I just wanted the peace-of mind with winter fast approaching),

And as far as I know the IMA (144V) battery module has never been replaced. The car performs well and typically gets an indicated 38 - 42 mpg in city use and close to 50 mpg highway. (We do live at 5000 ft ASL, which reduces mileage and power.)

About a week ago the IMA and CHECK Engine lights came on. (P1600 and P1433). At the time they come on the SoC dropped from 75% to roughly half that. Throttle response becomes noticeably sluggish, but the REGen/ASSist meter still works. And the SoC gradually moves up and down. The most I have seen it come back to is about 67 % when the codes are thrown.

When I clear the codes, I observe the following: REGen/ASSist immediately at idle shows (GREEN) charge and the SoC rapidly comes up to 100% within a couple of minutes. When the car is driven, throttle response is crisp and instrumentation shows "like-new" REGen/ASSist and SoC behavior in urban driving.

Then, usually with a day or so (usually less than 20-miles) the same codes return (P1600/P1433).

To the best of knowledge, the ECM has NOT been re-flashed or "Upgraded" by Honda.

1) Is there a way to determine the ECM Version level? Especially, from the factory built original version?

2) If a Honda dealer flashes the ECM, will it potentially mask the P1433 code? Making AH less likely to replace the IMA battery of DC-DC converter under warranty?

3) What is actually happening when the P1433 code is thrown? It seems to put the system into "LIMP" or "LAME" mode? This obviously affects the performance (Power and fuel economy) and places greater wer and tear on the ICE powertrain?

4) Does anyone have experience with Honda's Certified Used Car POWERTRAIN Warranty or Third-Party Warranties, with respect to premature IMA failures? I still have mileage and time remaining on my AH Certifed Used Car POWERTRAIN Warranty. Is the IMA Battery considered a POWERTRAIN component, or excluded because it is a battery?

5) Have any other Honda Civic Hybrid owners here joined the Class Action Suit against American Honda? See: http://www.hchsettlement.com/default.htm

Any advice (or dare I say Insights?) would be greatly appreciated.