TM   55-1520-240-T 7-8.5  APU  DOES  NOT  MOTOR  (Continued) ATTEMPT APU START. REFER TO TASK 15-1.4. DOES APU MOTOR PUMP SOUND LIKE IT IS   OPERATING? REPLACE APU MOTOR PUMP. HOLD SIGNAL HOSE TO APU MOTOR PUMP. ATTEMPT APU START. IS PRESSURE SURGE FELT ON HOSE? REMOVE ELEC PWR. DEPRESSUREIZE   UTILITY SYSTEM. REMOVE APU MOTOR PUMP. TRY TO TURN MOTOR PUMP SHAFT. DOES IT TURN? HOLD APU START PILOT VALVE. MOVE  APU SW FROM OFF  TO  START.  IS  THUMP FELT  ON  SOLENOID  VALVE? DISCONNECT PLUG 136P5 FROM APU START PILOT VALVE. CHECH FOR 28VDC BETWEEN PLUG 136P5 PIN 1(+)  AND  GROUND.  IS  28VDC PRESENT WHEN APU SW IS MOVE FROM  OFF  TO START? REPLACE APU. REPLACE APU START MODULE START VALVE. REPEAT OPERA- TIONAL  CHECK  TASK  7-8.3. DOES SYSTEM  CHECK  OKAY? LOCATE OPEN IN WIRE W668-136-22 BETWEEN PLUG 136P2 AND PLUG 136P5. REPAIR OR REPLACE WIRE AS REQUIRED. RELEASE SW. CHECK FOR GROUND ON PLUG 136P5 PIN 3.  IS  GROUND  PRESENT? LOCATE OPEN IN WIRE W668-GD129A22N BETWEEN PLUG 136P5 AND FUSELAGE GROUND. REPAIR OR REPLACE WIRE AS REQUIRED. REPLACE APU START PILOT VALVE. YES FAULT CORRECTED 7-8.8 END   OF   TASK 7-217