An excess traditional IRA contribution is a nondeductible contribution, so it can reduce the taxable amount of some otherwise unrelated traditional IRA distribution [not contribution as I mistyped originally]. It's possible that the resulting reduction in ordinary tax liability exceeds the 6% excess contribution penalty, causing a reduction in total tax liability for the year. However, you must make sure that you have properly entered into TurboTax the year-end balance in traditional IRAs, otherwise the calculation on Form 8606 of the taxable amount of the traditional IRA distribution will be wrong.
Correcting the excess contribution in a later year will still require a distribution of the entire amount of the excess, otherwise the 6% excess contribution penalties will continue, but some of that distribution will be taxable if some of the basis in nondeductible contributions that resulted from the excess contribution was already applied to earlier distributions, so there is no free lunch.
