Hitachi ZAXIS 120-6 class Operator's Manual page 114

4. When the troubleshooting is finished, fault code (7) is
displayed. Consult your authorized dealer to repair the
system.
f
NOTE:
 The main menu displays information about the Urea SCR
System Troubleshooting is only displayed when the Urea
SCR system alarm is generated.
 Up to 20 fault codes are displayed in chronological order.
OPERATOR'S STATION
1-32
7
MDC1-01-517EN