My MacBook Air 2017 model suddenly started facing this issue. My Mac won't turn on if not plugged in. The Mac shuts down automatically seconds after I unplug the Adapter. My Mac is 1 year 1 month and hence out of the service warranty. I want to fix this issue myself. I tried resetting SMC and PRAM and NVRAM but nothing helped. Apple Hardware Test resulted in a "No issues found". Kindly help.