I gather they meant an “Earth leakage fault”? While the detection circuit is inside the battery pack, the actual fault rarely (never) is. Most likely culprit is the AC compressor as mentioned in the discussion below:I have a 2012 iMiev with a 2 year old battery that I want to sell. About a month ago I went to drive it and got about 6 blocks when it slowed to a crawl and lights came on. I took it to Mitsubishi (MISTAKE) and they tell me it's the drive battery that has a "leak"??? and needs replaced at $13,000 and they won't cover it! I cannot believe that is correct, but I'm between two cities Springfield and KC, Missouri with each having ONE repairman. The battery shows a full charge and I think it has to be a resistor or whatever, besides the main battery, but I have NO options for someone knowledgeable to work on it. Interested?
https://myimiev.com/threads/solved-p1a44-p1a45-isolation-ac-pump.4439/