12S code in 12A box of W2

[libragrlphilly29]

was charged the amount in that box as tax...i don't think this is correct

[DianeW]

A or B:  This represents uncollected social security tax and medicare tax on tips.  If you have one of these codes and an amount it will care to other taxes to be paid with your tax return or reduce your refund.

S:  This code gives you information about contributions to your retirement plan at work, and it is for your information only.

The information will not carry over to taxable wages if the code is S in box 12. 

The information below may be helpful to understand your W2 codes.  If you believe the W2 is incorrect contact your employer to ask for a correction or explanation.
https://ttlc.intuit.com/replies/3300234