TM 10-3930-675-20-1 0012 00-3 ELECTRONIC CONTROL UNIT (ECU) INPUT VOLTAGE TROUBLESHOOTING - CONTINUED 0012 00 Table 2. Error Code 122 - Supply Voltage to Servo ECU (790) Failure Troubleshooting Procedures. MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION Error Code 122 - Supply Voltage to Servo ECU (790) Failure 1. Remove  cab  circuit  breaker panel and ensure that circuit breaker F32 is not tripped. Reset circuit breaker as required (WP 0073 00). 2. Check  batteries  for  loose  or damaged cables. Tighten or replace battery cables (WP 0108 00). 3. Check  relay  315  for  proper function. Replace  relay  if  shorted  (WP 0073 00). 4. Check automatic circuit breaker    F50-2    for    proper function. Replace     circuit     breaker     if shorted (WP 0073 00). 5. Disconnect ECU (790) connector  1  from  ECU  and perform voltage check at pin 7 and pin 8. If   voltage   is   present,   replace ECU (790) (WP 0079 00). 6. Check for voltage at connector X30 pin 2. If voltage is present, notify SRA. 7. Check  for  voltage  at  circuit breaker F32. If voltage is present, notify SRA to replace wire to (A302). 8. Check for voltage at relay 315 pin 87. If voltage is present, notify SRA to    replace    wire(s)    (A808A, A808B, and/or A808C). 9. Check for voltage at connector X80 pin 3. If voltage is present, notify SRA to replace wire (A804). 10.Check for voltage at automatic     circuit     breaker F50-2. If voltage is present, notify SRA to replace wire (A803). DIAG SERVO 1(13) SYSTEM POWER 24.00V POWER RI CAN 24.00V POWER LE CAN 24.00V 10V REF OUT 10.00V