Chosen Solution
After liquid damage to my Early 2011 MBP, I replaced my old 820-2963-B board with another board (same model number) from a Late 2011 13" MBP. I can power the computer on while it’s plugged in and the MagSafe has a constant green light. However, the battery icon had a black X over it. I replaced the battery with one from amazon and installed it today. The icon still has a black X and cannot run off of the battery alone. I reset the SMC and reseated the battery. Still nothing. The battery indicator lights on the side also do not work. I tried to run it with the BIL disconnected but the battery is still not recognized. The replacement board I bought was refurbished I believed and guaranteed to work by the seller on eBay. The battery I purchased was from amazon and is a Siker. UPDATE: The X has gone away and now shows the Lightning symbol over the battery icon but it remains stuck at 0% and says that the battery is not charging. Here is my information from coconutBattery: Current charge: 0 mAh Max charge: 0 mAh Design capacity: 0 mAh 0 cycles Battery Status: Good Battery Temperature: -273.1 degrees Battery Failure: None Charging with: 0.0 watts UPDATE 2: I do not know if this helps but I ran an extended Apple Hardware Test and came up with the error code 4SNS/1/40000000: VDOR -18.707. I know this is some sort of Voltage DC sensor. I did not replace my DC-In when I replaced the board and am not sure if that is where the sensor is located. UPDATE 3: I replaced the Battery Indicator Lights but they will not turn on at all. However, the AHT no longer reports any errors and the System Profiler now comes up with a power page (whereas before I replaced the BIL it did not). Techtool Pro 8 does not recognize any sensor failures either and reports that the battery passed it’s test. It still does not show up in coconutBattery and continues to have a black X.
Im going to guess the BIL connector may be faulty. The temp reading is way off which the SMC may be shutting the charging circuit off because of it.
Ok, if its a liquid damage, there is a high possibility that plug which connects the battery and the motherboard damaged. The pins of the plug may have been damaged due to electric shorts when the pins were exposed to the liquid. You might want to buy the plug and perhaps replace it to the one soldered to the motherboard. It might be the case
