Since TurboTax does provide an indication that you've entered a Roth IRA contribution in excess of the permissible amount, TurboTax not alerting you about an excess Roth IRA contribution implies that you omitted, incorrectly entered or changed some information in your tax return that was necessary to determine that you made an excess Roth IRA contribution. For example, you might have entered a Roth IRA contribution and subsequently entered additional income that put you over the MAGI limit for making that much of a Roth IRA contribution. Under these circumstances, unless you revisit the Roth IRA contribution questions you won't see an explicit indication of an excess Roth IRA contribution. You'll just have Form 5329 appear with the calculation of the excess contribution penalty which you would need to notice when you review your entire tax return before filing.
