KEYLOAD FAILURE
Synopsis
This failure relates to only secure equipped radios 
and indicates a failure to load key with the KVL 
indicated by the message “KEYFAIL” and keyfail 
tones.
Typical failures would be :
1) Open between the GCAI connector and the  
microprocessor which prevents the keyloading.
2) Use of the wrong KVL or keyload cable.
3) Failure of the secure circuitry.
4) No secure personality in the radio codeplug.
With KVL attached to radio 
and radio on, verify display 
message “KEYLOADING”
Correct 
Equipment?
Activity?
Keyloading 
Message” 
displayed?
With KVL attached to the radio
and radio on, initiate a keyload
from the KVL and look for activity
on keyload signal at the P1000_4
connector on the GCAI Flex. 
Obtain correct KVL 
and cable
Yes
Yes
No
Yes
Verify GCAI data path.
Check the following 
signals: GPIO4, One Wire
Repair connector using 
programming failure 
flowchart for details.
No
No
Inspect GCAI 
flex to board 
connections and 
Replace GCAI
  Flex if 
necessary
With KVL attached to the radio
and radio on, initiate a keyload 
from the keyloader and look
for activity on keyload signal at
P1000_21 on Front Kit Flex. 
Activity?
Replace Front Kit
          Flex 
     Check signal at
Front Kit connector on
 the keypad P2000_21 
Yes
Activity?
Yes
Check and repair Front Kit flex
  connector to Keypad board
              connector 
No
      Check signal at
R2005 on keypad board 
Activity?
   Check and repair
keypad to main board
     connection from
       P1000_21 to
          J2031_21 
No
       Check signal at
   main board connector
           J2031_28
Activity?
     Inspect 
     U4003.
    Measure
  power pin5? 
No
V = ~5.0V?
No
    Proceed to
      DC Flow 
         chart
Inspect U4003
with keyloader
    attached.
Measure mux
  select pin6.
V = ~0V
   Inspect Q4001 with
keyloader attached . 
Measure BJT input pin2.
No
Yes
Replace U4003
V = ~1.8V
No
Yes
Replace main
       Board
Replace Q4001    
Yes
  Initiate a keyload 
    and check for 
activity at R2501 of
       Keypad
Yes
Activity?
No
  Check and repair 
keypad to main board
 connection from
   P2001_22 to 
      J2301_22
 Replace Keypad
         Board
Yes
No
Yes