Refer to the IRS.gov website for the current codes they require. These are in some cases different that those used by the core system and CU*Answers, listed below.
 
Contribution/Distribution Codes CU*Answers
1—Early distribution, no known exception. 
2—Early distribution, exception applies.
3—Disability. 
4—Death.
5—Prohibited transaction. 
6—DOES NOT EXIST
7—Normal distribution.
8—Excess contributions current year
9—DOES NOT EXIST
A—DIRECT TRANSFER
B—DOES NOT EXIST
C—Current Year Contribution
D—Death
E—DOES NOT EXIST
F—Federal Withholding
G—Rollover to a qualified plan
H—Conversion contribution to a Roth
J—Early distribution from a Roth IRA, no known exception.
K—State Withholding
L—Rollover Contribution
M—Recharacterized Contribution
N—Recharacterized Contribution current year
P—Excess contributions prior year
Q—Qualified distribution from a Roth IRA.
R—Recharacterized contribution prior year.
S—DOES NOT EXIST
T—Roth IRA distribution, exception applies.
U—Qualified Reservist Repayment
W—Direct Transfer
Y—prior year contribution
Additional codes that appear on transactions:
O—Other withdrawals
I—Internal transfer non reported
V—Dividend
X—Qualified disaster repayment
Z—Qualified birth/adoption Repay