Starting System
Generator Control Unit LED Fault ID Display and Indications
 

The set of four LED fault indicators located on the face of the Left and Right Generator Control Unit (BT001 and BT002) illuminate to display a fault pattern.  Refer to the following table for a description of each fault pattern:

NOTE:  Fault patterns are read from left to right with technician looking at the face (display area) of the GCU.

Fault Code Legend

Description

LED Illuminated

LED Extinguished

 

NOTE: The following indications are visible only with the L GEN or R GEN Switch (SI025 or SI026) held in the RESET position.

LED Fault Pattern

Fault Displayed

Function

NO FAULTS No faults; system functioning properly. 
BUILD UP GF Build up ground fault - generator current >200A while power relay (KLC) was off. 
OPEN POR  POR (pin B) sensing wire open 
QIKTRIP OV Quick Overvoltage trip (GCU failure) 
GROUND FAULT Ground Fault according to CT signal - pin M to m. 
OVEREXCITE Overexcitation - check pins W and p. 
OVERVOLT Overvoltage detected. 
OPEN SHUNT Open shunt engine start - check connections to generator - pins (AA, DD, y, B).
SHORT SHUNT Field current exceeded 20A on pin AA. 
KFR BIT FAIL Failed KFR (GCU failure) field relay inside GCU. 
GF BIT FAIL Failed GF test (GCU failure)
REGULATOR Regulator failed to energize during engine start (GCU failure).
KLC SHORT Line contactor driver (pin L or J) overloaded or failed to turn ON. 
KSR SHORT Start contactor driver (pin L or J) overloaded or failed to turn ON.
MPU Open No speed pickup (pin X to Y) signal. 

NOTE: The GCU cycles through all the LEDs at power up to test their operation. Under some conditions the SYS LED may flash after completion of test series. This is a normal condition. The flashing LED may be
extinguished by selecting the L GEN  or R GEN switch ON/OFF/RESET switch from OFF to RESET three times within three seconds. This procedure will clear any of the fault lights if the fault has been corrected.