Hi

I have a 2006 FEH with ~120,000 miles. It mostly drives fine except I am noticing that it increasingly seems to lose charge over night or within a few days of not being drive. It turns on and drives but with no hybrid assist/very slow acceleration for the first ~15 minutes of driving. The hybrid cooling system also seems to be faulty in that the battery will heat up and not allow the vehicle to kick into hybrid mode. There is a short window (between 15 to 45 minutes of a given drive) when the battery is charged enough and cool enough to allow Hybrid mode.

(A mechanic recently told me that if the battery isn’t charging because it is overheating it might be why it has low SOC the following drive… seems plausible to me)

I have BCM codes P0A81-60 and POA1F-20 and PCM codes P2521 and P2524 (screenshot attached)

I have never gotten a stop safely message while the vehicle has been warm and running ForScan for the last month or so I haven’t seen the hybrid battery get hotter than 108 even while be driven for hours on end on recent Death Valley road trip

From ForScan I also have seen a large difference in SOC and temperature between individual battery cells. For example the max charged cell will have 80% SOC while the minimum cell will only have %40 SOC. And once at “operating” temperature cells with have a ~20 degree range from hottest to coolest. Is this normal or does this indicate bad cells? (screenshot attached to illustrate point)

Other potentially pertinent info: The low voltage under the hood battery seems to be fine and AC blows pleasantly cool in the cabin. Both the HVTB service harness was replaced and BCM was reprogrammed in 2018 ~40,000 miles ago. Over the 50,000 miles I have owned the car I have gotten reliably between 24 and 27 MPG and haven’t noticed any declines with the recent increase in issues. I wonder if these issues have always been present and are getting worse?

Questions:

• Do I have both a failing hybrid battery and a failing hybrid cooling system or would replacing the hybrid battery fans fix both issues?
• If both parts of the system are failing would buying a new battery include the fans?
• I might be able to replace the fans myself, but I don’t want to replace the fans, if fans are included with a replacement battery.
• Is it possible only some cells are bad, and I could have the battery reconditions for less than the cost of a full replacement battery?
• Are there any other possibilities I should explore? Any other Information that I can pull in ForScan that would be helpful?

The car still drives fine enough, the frequency of these hybrid issues are starting to get a little annoying and I am starting fear getting stranded or having the hybrid system over heat on the highway. I have loved this car and would like to see it keep rolling, everything else mechanically on this car seems to be in good shape, but I'm not sure how much money would be wise to spend diagnosing and repairing the hybrid components. Sorry for the info dump, any advice would be appreciated!


P Codes present.

ForScan Info I have been keeping an eye on.