Hello Raul.
Error 54 is motor cable broken or cable for temperatur sensor. If you have changed controllers, check for bad connections. Also check the small connector (6 pins) on motor. Does display write any text beside error 54? Does this forklift have 3 MP1514 Controllers??? If so you can't replace or interchange controllers without reprogramming interface and controllers. Either by LISA or by laptop/judit.
Regards, Max
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