I own a FEH 2007, 111k miles. The 12V battery had a little bit of corosion (blue powder around the positive terminal). After sitting for two months in the garage w/o driving (wife and kids were on a long vacation with in-laws) the 12V battery was fully discharged. I had it recharged and tested for functionality and according to Walmart it is fully functional. I put it back into the car, noticed also some light corrosion on one of the battery cables, but lights, radio etc were all working fine. However, suddenly the „Stop safely now“ popped up on the display. The car would not start anymore. Before towing it to the dealership I checked with the key turned whether the MEC pump was working. My impression was it was not (no bubbles in the cooling liquid, no movement of the pump itself). However, the dealership told me that they do not think that it is the MEC pump. They read the error codes and got P0A08 (DC / DC CONVERTER STATUS CIRCUIT / OPEN) and P0A0C (HIGH VOLTAGE SYSTEM INTER-LOCK CIRCUIT LOW) . They called me and told me that we need to replace the DC/DC converter which I agreed to – luckily I bought a used one. The car would still not start. They’ve been struggling with the second error code over 5 weeks (!!) w/o any resolution. I suggested to replace all of the relays what they did however that did not resolve the issue. They called me today and told me that Ford would not cover any further diagnosis work and they believe that it is the transmission. When I asked for a cost estimate for further diagnosis and potential replacements they said they cannot tell but it could be everything between 400$ and 5000$ and they don’t think that it is economic. Due to the long time it took them to work on the diagnosis/(missing) cause of the second DTC (car now 45 days at the dealership), their bad communication style (I always had to call to get an status update) and Ford’s lack of commitment to resolving this Hybrid issue I am very suspicious of their capabilities and in particular their conclusion about the transmission. Any advice of potential causes for P0A0C would be highly appreciated! Also any recommendations for a trustful Hybrid technician in the Greater Houston/Spring,Texas, area would be helpful. I have not given up on my vehicle! Thank you.