Remove the bottom case.
Remove the battery connecter from the logic board.
press and hold the power button
plug the charger into laptop.
wait for 10-15 sec with holding power button and charger ins to it.
release the power button and press it again.
your macbook will sure power up.
this is the process to bypass the SMC which diagnose the whole laptop during starting up. i have a same a1342 with liquid damage . but power up with this process but battery is not working . every liquid damage is working with this process. thnx