As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
JUST PRIOR TO PUSH BACK WHEN ATTEMPTING TO SWITCH FROM GROUND POWER TO APU, NOTICED NO VOLTS ON APU. ALSO, NOTICED APU BLEED AIR VALVE CYCLING ON AND OFF. SHUT DOWN APU. ATTEMPTED RESTART, UNSUCCESSFUL. APU FAULT LIGHT ILLUMINATED. ACFT GROUNDED. REPLACED APU FUEL CONTROL REF MM 49-31-11OPS & LK CK GOOD.