IBM 3270 Maintenance Manual page 322

8. Press 0 (RUN DIAGNOSTIC ROUTINES)
then Enter.
9. Depending on the configuration of your
system, questions about attached devices may
appear on your screen. Press Y or N as
required, then press Enter.
10. Press Y or N (IS THE LIST CORRECT?) then
Enter. (If the list is not correct, follow the
instructions on your screen and correct the
list before answering yes. If you cannot
correct the list, you still must answer. yes
before you can continue.)
11. Press 0 (RUN TEST ONE TIME).
12. Select 18 (EXPANSION OPTION) then press
Enter.
TESTING - EXPANSION OPTION
x:xX:xx
ERROR -
EXPANSION OPTION 18XX S
Data - XXXX= XX / XX SW= X
PRESS ENTER TO CONTINUE
DID YOU GET AN 18XX ERROR CODE?
NO Go to page 3-1800-14.
YES
October 1984 3-1800-7