Sarah Posted August 15, 2020 Report Share Posted August 15, 2020 (edited) Hi, I recently bought a Ford C-Max Energi I had a yellow wrench signal come one, so decreased power though. When I turned the car off and back on it had gone away. I took it to the mechanic and they read the error code (P0dd6) and said one that indicates one of the batteries needs replacing but they couldn't tell me which one although they think it’s the electric one. Is there any chance this is a weird glitch that a software update might resolve or maybe the 12v battery needs to be replaced? Nothing has happened to the car and it isn't acting weird except that light coming on one time. It also only has 102,000 miles on it which seems really odd for the battery to die that young. I'm a student without that much extra cash on hand. Any tips or advice would be greatly appreciated! Is there any way for me to find out if the electric battery actually needs to be replaced without paying a large fee to have a ford dealer look at it? And if it does and it's not some weird glitch, is there anyone who fixes ford electric batteries? I definitely can't afford a new one... Anyway this is all super stressful for me. Edited August 15, 2020 by Sarah Quote Link to comment Share on other sites More sharing options...
plus 3 golfer Posted August 15, 2020 Report Share Posted August 15, 2020 P0DD6 - Hybrid/EV Battery Cell Balancing Circuit "K" Stuck Off. Your High Voltage Battery consists of 84 individual lithium ion cells. The 84 cells are grouped in 14 groups of 6 cells per group. PDD6 indicates Group K was "stuck off" meaning that group of cells will not be balanced if it would be stuck off prospectively. However, since in only happened once, I wouldn't be concerned and besides there's really nothing to do. It may simply by a one-off anomaly and never happen again. Below is an excerpt from the Ford 2017 OBD System Operations Manual for HEVs on cell balancing. Cell Balancing: Individual cells can deviate over the life of the high voltage battery. The purpose of cell balancing is to equalize the individual cell charges. By balancing the cells the high voltage battery maintains top efficiency. The BECM continuously monitors individual battery cell voltages and will perform balancing automatically only when required. When balancing is performed BECM discharges individual cells with the highest voltage to match the remaining cells. Monitor execution: At a power up before contactors are closed, and two consecutive power cycles. Quote Link to comment Share on other sites More sharing options...
Sarah Posted August 15, 2020 Author Report Share Posted August 15, 2020 @Plus 3 Golfer Wow, thank you so much! That answer really called me down. If it does happen again, what would that mean/ what should I do? Quote Link to comment Share on other sites More sharing options...
plus 3 golfer Posted August 15, 2020 Report Share Posted August 15, 2020 (edited) If the cells are never balanced in a group, the strongest cell(s) in the group will be overcharged and the weakest cells in the group will be undercharged. Over charging cells lead to premature aging (faster loss of storage capacity). Also, as the battery pack is being discharged, the weaker cells could be discharged below their minimum operating voltage which could lead to failure. The BECM monitors voltage variances among cells in the group and will set a DTC should the voltage exceed limits. So, if cells never get balanced, my guess is that eventually a DTC would be set for voltage difference exceeded. So, until one sees these DTCs, I doubt again there is anything to do. Edited August 15, 2020 by Plus 3 Golfer Quote Link to comment Share on other sites More sharing options...
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